Homeschooling your kids?  Learn how to use our weekly math learning plans

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Language: en

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- Hello, welcome.

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We are so glad to have several of you,

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a few hundred already, here today,

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and really appreciate your time.

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My name is Dave Herron.

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I work on our team that supports teachers

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and school districts at Khan
Academy, and I am joined today,

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about two miles away, from
her home in San Francisco,

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by my colleague Vicki Lang,

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who is a learning scientist on our team.

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So hello, Vicki.

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And I'm also joined by my colleague Dan,

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who helps lead our marketing team

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from San Mateo, California.

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Hi, Dan, and he will help actually, me,

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surfacing some of your questions
all throughout the webinar,

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and we'll leave the last
few minutes of the webinar

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to answer as many as we can.

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And so you'll see a question
tab on the GoToWebinar panel,

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and if this is your first webinar with us,

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then go ahead and take a look at that,

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and at any moment when a
question pops into your head,

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please put that in there
so that we can do our best

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to answer as many as possible.

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We're here to spend the
next 30 minutes or so

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on the topic you should
be seeing on your screen.

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Some of you may have found
yourself over the last

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four or five, six weeks, maybe,

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suddenly as homeschool
teachers, in addition to

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all the other responsibilities
you're balancing.

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We know it is a whole lot to juggle.

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Here at Khan Academy, we
have created daily schedules

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and now weekly math learning plans

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to try to support you
as you support your kids

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so that they can stay on
track as much as possible

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in their math courses,
as well as other courses,

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that they may be missing in school.

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And so we're here to break
down these plans for you,

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and I wanna thank, before we move on,

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some of the key supporters who
have been providing support

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to Khan Academy so that we could increase

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the amount of support we're
providing throughout this time.

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And you'll see those
names there on the screen.

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Our main goal is to break
down the plans for you,

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explain all the ins and outs

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of these weekly math
learning plans, and again,

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answer as many of your
questions as possible.

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And before we move on,
I'm going to start a poll

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to see how familiar this audience is

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with the learning plans
that we're talking about.

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So take the next few seconds,

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once it pops up on your screen,

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to tell us what best
represents your familiarity.

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Are you I've never seen them before,

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I'm here to learn, or I've seen them,

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but I have not used them with my kids,

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or finally, I have started
using them already with my kids.

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We'll take about 10 more seconds.

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If you haven't yet, fill in your vote.

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Three, two, one, about two-thirds of you

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have submitted your vote,
and here's where we're at.

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Over half of you have never seen

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these learning plans before, so thank you

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for joining despite not
having that past familiarity.

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We'll walk you through how to find them.

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And then the others, about
a quarter, have seen them,

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but haven't started using them,

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and we do have some maybe
intermediate or advanced users

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who have already started
using them with your kids.

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We'll be really
appreciative of any feedback

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or questions that you
have since you're already

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started using them, and we have a survey

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at the end of the webinar if
you wanna give us more advice

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on how we can improve
them and move forward.

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So given that over half of you
have never seen them before,

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let's start with a pretty basic question.

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I'll take this one, Vicki.

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How do I even find the
learning plans to begin with?

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If you go to our website
at khanacademy.org,

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on the very home page, which
you should see an example of

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on the screen now, there will
be a blue banner at the top.

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That links you to some of our
remote learning resources.

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And if you click that
link, you'll be brought

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to that page that's shown on
the right side of the screen,

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where one of the main options
are the weekly learning plans.

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That will give you access
to all of the learning plans

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that we've created so far.

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We have them at many different
grade levels for math,

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and we recently published
a high school biology

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learning plan as well.

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They are all in a format
that's very easy to print

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if you do have a printer
accessible for you.

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We know the learning plans
for kids are often helpful

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to have in print form,
and so when you open it,

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you may notice the
formatting looks different

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than the regular Word document,

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but that makes it easy
if you press control-P

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or whatever the shortcut is

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on your computer to print those out.

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You might be multi-tasking right now

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and following those steps to
access the learning plans,

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and just those two other quick reminders.

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I should've mentioned this
right at the beginning,

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but there is a copy of these slides

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available to download as
a PDF within the browser

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that you have available, and then second,

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we're recording the webinar,

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and we'll send you a copy
of the recording soon after,

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within a few hours after the conclusion.

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Let's move on, though.

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Who are the plans for?

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What's the big goal or idea
behind these plans, Vicki?

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- Well, as you said, they're for students

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from 3rd grade through high
school for mathematics,

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and then we also have one
for high school biology,

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and they're really for
providing a clear goal

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for what to work on week to week.

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We know that it's great
to set a large goal

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of being ready for next year
when school starts again,

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and it can also be really
helpful in reaching that goal

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to break it down into smaller steps.

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We're breaking that goal down

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into week-by-week-by-week
steps to get you ready,

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or your child ready for next year.

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On the next slide we can
see that the real audience

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for this is folks who's districts maybe

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have not provided enough support,

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or you're looking for
something a little bit beyond

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what your district has provided for you.

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This is an overwhelming
time for school districts.

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What they've been able to
provide has really varied,

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and we wanna make sure that everybody

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has access to a plan that they can use

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to make sure that your kiddos

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are ready for school next year.

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- Perfect.

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And as you mentioned,
these are far more specific

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than the daily schedules
that we've put up.

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I know we're receiving
this question already

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in the chat room that
think of a daily schedule,

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saying, maybe at this time per day,

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you can work on this course,
if you're in 6th grade.

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The weekly learning plan is
gonna get way more specific

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on what unit and what
the actual goal could be

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to complete by the end of it.

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So let's talk about that.

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What would you need to know
about the learning plans

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to just even get started on
that first day with your kids?

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- Well, if we look at a
sample, and we can look

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at that 6th grade sample learning plan,

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and I'll just show you
how it's structured there.

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At the beginning, there's
gonna be some instructions

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about how to use it, as well as,

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you can see it says click
here for explainer video.

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That's a short video where Sal talks more

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about what to do with it.

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And then there's some instructions here

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about how you're going
to get your kids started.

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Let's, for example, talk about a kiddo

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who was supposed to be
finishing 6th grade right now,

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will be entering 7th grade next year.

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They've already learned probably

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a lot of the 6th grade content,
so this is gonna explain

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to have them start with
the course challenge

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to earn credit for the things
that they already know,

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and Dave will talk more
about that in a few minutes,

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about how that mastery system works,

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and the course challenges works,

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but they're gonna get credit for

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what they already know
by taking a pre-test.

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And then they're going to, in the system,

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have a to-do list of work that
they haven't mastered yet,

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and that's gonna map onto this table here.

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So what you're seeing in this table

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is the 20-week version
of finishing 6th grade,

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and the 20 weeks will take
you right up to August

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to when 7th grade would begin.

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And in this table, you'll
see that each row is a week

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with an end date on Friday,

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and then the color changes represent

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a different unit of
instruction that's starting.

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So for example, in this
one, in the first week

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that student would take
that course challenge

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to pre-test out of some of the content.

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Then they would begin the ratios, rates,

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and percentages unit,
and they would be aiming

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to get about 600 points
that week in that unit.

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The next week they would
continue work on that unit.

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It's a pretty big unit.

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They would aim to get to 1200 points.

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That's another 600 points
for a total of 1200.

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The following week, they
would aim to get to 1900,

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and they would move on to the next course,

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or to the next unit, I mean.

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You're going to wanna decide

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between the 20-week and
the 12-week options.

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If you would keep scrolling down here,

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you would see that
there's a 12-week option

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that has you finished by the end of June.

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And that just depends on how
much time you wanna invest.

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You're gonna be able to fit
in a little bit more content

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if you're with the 20-week option,

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but we wanted to make sure
that if you wanna spend

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only a shorter amount
of time and get to maybe

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the time when the school year
would typically have ended,

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that you're able to hit
all the really high points,

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so that's what the 12-week one does.

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And then if you keep
scrolling, you'll notice

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there's another pair of tables,

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and these are for a
foundational learning plan.

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So those first two
tables tell a 6th grader

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how to finish 6th grade.

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The second pair of tables give you a plan

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for our arithmetic class,
which is a foundational

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skills class that supports 6th grade.

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So if you have even more time

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that you wanna invest in 6th grade,

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or if your student is
struggling a little bit

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with 6th grade, you
might have them also work

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on this arithmetic course to build

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some of those foundational
skills to support it.

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And that's kind of what
you need to know there,

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and then if we look here, we can see that

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the most important time in
getting these learning plans

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off the ground, or really,

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in getting anything off
the ground with a kid

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is the first two weeks,
the beginning of it,

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where you wanna really
establish your routine

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and get into a pattern with it.

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And you can, things that
can help you with that

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are making the plan physical.

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If you do have a printer, print it.

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If you don't have a printer, sketch it out

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on a piece of paper.

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Make it a place where they
can write and interact with

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and really see on the
refrigerator or somewhere,

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and making it a clear habit,

00:10:01.537 --> 00:10:03.150
where there's a routine to it.

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First, I'm gonna check my goals.

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Then I'm gonna open and do some work.

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Then I'm gonna record
my progress every day,

00:10:09.450 --> 00:10:11.593
at the same time every day, maybe.

00:10:12.645 --> 00:10:15.760
And with that, let's
see if Dave can tell us

00:10:15.760 --> 00:10:17.400
a little bit more about
the mastery system,

00:10:17.400 --> 00:10:18.940
'cause those tables really are grounded

00:10:18.940 --> 00:10:22.010
in getting to about 70%
mastery on each of those units,

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so we need to understand
what those points are

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and how you get mastery
and how that would work.

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- Absolutely, so as Vicki just showed,

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there are references to different
point goals for learners

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all throughout these learning plans.

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And we know that it is
motivating to have a clear goal,

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but it's also, I'm sure, helpful for you

00:10:42.430 --> 00:10:47.110
as the parent or adult
to just be able to know

00:10:47.110 --> 00:10:49.210
how those points are maybe calculated

00:10:49.210 --> 00:10:54.210
and how to encourage your
kids to achieve those goals.

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Let me show you a few screens.

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This on the screen right
now is our 3rd grade plan.

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This would be 3rd grade common core,

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and on the left-hand column
are all the different units

00:11:07.420 --> 00:11:10.000
in our 3rd grade math course.

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And on the right-hand
side are all the points

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available for each unit.

00:11:14.042 --> 00:11:16.970
Every unit has a certain number of skills,

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and every skill is a hundred points.

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In the unit at the top,
maybe it's worth 800 points.

00:11:22.850 --> 00:11:25.200
It's got eight different skills in it.

00:11:25.200 --> 00:11:27.070
Those points are really important

00:11:27.070 --> 00:11:29.020
for understanding the learning plans,

00:11:29.020 --> 00:11:32.980
because all of the goals
reference unit mastery points.

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The other thing I wanna
mention is Vicki alluded

00:11:35.840 --> 00:11:37.950
to the course challenge.

00:11:37.950 --> 00:11:40.210
If we were talking maybe in September

00:11:40.210 --> 00:11:42.000
or near the start of a school year,

00:11:42.000 --> 00:11:44.880
then a course challenge may not be

00:11:44.880 --> 00:11:46.242
the first step for a student

00:11:46.242 --> 00:11:48.900
if they're just getting
started on third grade.

00:11:48.900 --> 00:11:50.561
But considering that it's springtime

00:11:50.561 --> 00:11:53.259
and that your kids have
already learned a lot

00:11:53.259 --> 00:11:56.420
of math this year, the
course challenge could be

00:11:56.420 --> 00:12:00.680
a great way for them to quickly place out

00:12:00.680 --> 00:12:03.298
of some of the skills that
they're already confident in.

00:12:03.298 --> 00:12:07.000
So I would guide your kid to
click on the course challenge

00:12:07.000 --> 00:12:09.280
as the first step, and
it will scroll them down

00:12:09.280 --> 00:12:11.601
to the very end, actually,
and they'll get started

00:12:11.601 --> 00:12:14.380
on that mixed review of
all the different skills

00:12:14.380 --> 00:12:15.660
from throughout the year.

00:12:15.660 --> 00:12:18.510
Just remember to remind
them that it's totally okay

00:12:18.510 --> 00:12:19.720
if you don't know these answers,

00:12:19.720 --> 00:12:21.930
'cause they'll include
some from the later units

00:12:21.930 --> 00:12:23.680
that they may not have learned yet.

00:12:24.880 --> 00:12:27.525
I also wanna show a brief
video that goes over

00:12:27.525 --> 00:12:30.606
some of the other learning
experiences for students

00:12:30.606 --> 00:12:32.756
so that I can explain a bit

00:12:32.756 --> 00:12:35.370
about what you might be
seeing in the next few days.

00:12:35.370 --> 00:12:40.370
Here I'm, as a learner,
clicking on that blue button

00:12:40.640 --> 00:12:43.600
just a minute to start in on a lesson.

00:12:43.600 --> 00:12:47.270
Here we're in addition and
subtraction within 100,

00:12:47.270 --> 00:12:49.904
and there's gonna be a
bunch of learning resources,

00:12:49.904 --> 00:12:51.710
our videos and articles,

00:12:51.710 --> 00:12:54.070
and then there's gonna
be practice resources.

00:12:54.070 --> 00:12:57.280
So I'm clicking on that
first practice problem set.

00:12:57.280 --> 00:12:58.940
The practice problems,
some of them are gonna be

00:12:58.940 --> 00:13:01.000
only four problems, some seven.

00:13:01.000 --> 00:13:03.060
The longest might be 14 if it's like

00:13:03.060 --> 00:13:05.130
a lot of procedural fluency.

00:13:05.130 --> 00:13:07.710
And if I'm stuck on a
problem, what I just did is

00:13:07.710 --> 00:13:09.128
I clicked on a video.

00:13:09.128 --> 00:13:11.800
It was listed right
there, because it's really

00:13:11.800 --> 00:13:15.540
closely aligned to the
practice that I'm doing.

00:13:15.540 --> 00:13:16.980
If I'm done watching the video,

00:13:16.980 --> 00:13:20.320
and now I know how to do
this problem of 92 plus 3,

00:13:20.320 --> 00:13:23.110
then I can answer it, 95.

00:13:23.110 --> 00:13:25.770
If I'm still not sure, I could get a hint.

00:13:25.770 --> 00:13:27.720
And the hint is gonna
mark the problem wrong,

00:13:27.720 --> 00:13:29.072
'cause it gives away the answer,

00:13:29.072 --> 00:13:31.522
but encourage your kids to take hints.

00:13:31.522 --> 00:13:33.340
When you look at the research,

00:13:33.340 --> 00:13:34.890
the kids that take more hints,

00:13:34.890 --> 00:13:37.160
even though they're getting
the initial problem wrong,

00:13:37.160 --> 00:13:40.222
they end up making
faster progress over all.

00:13:40.222 --> 00:13:41.970
I'm getting the questions right.

00:13:41.970 --> 00:13:43.940
I'm getting instant feedback on this.

00:13:43.940 --> 00:13:45.890
You might see the little
dots at the bottom

00:13:45.890 --> 00:13:49.476
of the screen turning green,
so I've got a few more to go,

00:13:49.476 --> 00:13:54.476
and if I do get to a 70% or higher,

00:13:54.850 --> 00:13:56.330
then I'm gonna get points.

00:13:56.330 --> 00:13:59.150
In this case, I'll get half
the points for that scale, 50,

00:13:59.150 --> 00:14:02.280
so that's contributing to that
goal in the learning plan.

00:14:02.280 --> 00:14:05.217
And I'm just about to finish
with the last problem,

00:14:05.217 --> 00:14:09.090
and because I'm about to ace,
I think, this problem set

00:14:09.090 --> 00:14:10.790
and get 100%, I'm gonna get

00:14:10.790 --> 00:14:12.900
almost all the points for this scale.

00:14:12.900 --> 00:14:14.350
So there should be some confetti

00:14:14.350 --> 00:14:16.510
that rains down from the ceiling.

00:14:16.510 --> 00:14:18.700
I just received 80 points.

00:14:18.700 --> 00:14:22.140
Not quite a hundred, because
there's just one practice set,

00:14:22.140 --> 00:14:24.090
and I haven't shown that
I still understand it

00:14:24.090 --> 00:14:26.830
when it's mixed in with a
whole bunch of other concepts.

00:14:26.830 --> 00:14:28.791
But I'm on my way towards
my goal for that week.

00:14:28.791 --> 00:14:32.871
So if I go back to the unit overall,

00:14:32.871 --> 00:14:35.700
then I'll see here in the top left corner,

00:14:35.700 --> 00:14:39.136
I have now a total of 240 points.

00:14:39.136 --> 00:14:41.940
So I know that was brief,

00:14:41.940 --> 00:14:44.780
but that's kind of the
three-minute version

00:14:44.780 --> 00:14:46.244
of our mastery system.

00:14:46.244 --> 00:14:49.340
I think it's closely related to a question

00:14:49.340 --> 00:14:50.500
we've already been hearing a lot,

00:14:50.500 --> 00:14:53.722
how do I know if my kids are on track?

00:14:53.722 --> 00:14:56.370
We do have parent accounts

00:14:56.370 --> 00:14:57.952
that you can create on Khan Academy.

00:14:57.952 --> 00:14:59.950
When we designed those parent accounts,

00:14:59.950 --> 00:15:02.040
it was in a pre-covid world,

00:15:02.040 --> 00:15:03.543
where we did not expect parents

00:15:03.543 --> 00:15:07.870
to be homeschooling en masse,
and so the amount of detail

00:15:07.870 --> 00:15:09.750
you'll find on there will be helpful

00:15:09.750 --> 00:15:11.700
for getting an overview of how much time

00:15:11.700 --> 00:15:14.620
your kids are spending and what
they've worked on recently,

00:15:14.620 --> 00:15:16.341
but it's not gonna give
the detailed points

00:15:16.341 --> 00:15:18.150
that you might need to tell

00:15:18.150 --> 00:15:20.262
if they're on track for the learning plan.

00:15:20.262 --> 00:15:23.710
Instead, what we recommend
is just having your kid

00:15:23.710 --> 00:15:26.432
maybe once every few
days, maybe once a week,

00:15:26.432 --> 00:15:28.053
whatever might work for you,

00:15:28.053 --> 00:15:31.730
showing you their screen and
talking about how it's going,

00:15:31.730 --> 00:15:33.370
and then you can look
at the points together

00:15:33.370 --> 00:15:36.040
and turn it into a conversation of sorts.

00:15:36.040 --> 00:15:37.862
Here again, on the right-hand,
I'll see the point values

00:15:37.862 --> 00:15:42.862
for each unit, and that,
if I'm just to sort of

00:15:43.520 --> 00:15:45.438
do a crosswalk for the learning plan,

00:15:45.438 --> 00:15:48.840
then on the screen, you'll
see intro to multiplication.

00:15:48.840 --> 00:15:51.618
I currently have 660 points.

00:15:51.618 --> 00:15:53.840
So I've written that in there in pink,

00:15:53.840 --> 00:15:55.530
into the second week of the learning plan.

00:15:55.530 --> 00:16:00.320
I'm so close, but good news,
in one-digit multiplication,

00:16:00.320 --> 00:16:03.593
I have 1,050 points, so
I've exceeded my goal.

00:16:06.960 --> 00:16:09.670
The last one that I wanna talk over is

00:16:09.670 --> 00:16:12.830
how you might help your
kids when you are stuck.

00:16:12.830 --> 00:16:15.240
I taught 9th grade algebra one

00:16:15.240 --> 00:16:17.640
for most of my teaching
career, and even though

00:16:17.640 --> 00:16:20.450
I was a math teacher, if
I was asked by someone

00:16:20.450 --> 00:16:23.650
more of a 4th grade level on
how to break down a skill,

00:16:23.650 --> 00:16:25.359
it would be tough,
because it's hard to know

00:16:25.359 --> 00:16:28.530
how to teach something at that level,

00:16:28.530 --> 00:16:30.710
given what they understand currently.

00:16:30.710 --> 00:16:34.034
So don't feel the pressure that
you have to be the teacher.

00:16:34.034 --> 00:16:36.540
Instead, if they come to
you and they're stuck,

00:16:36.540 --> 00:16:38.618
and they're saying one
topic's really confusing,

00:16:38.618 --> 00:16:41.170
one strategy we recommend is just to watch

00:16:41.170 --> 00:16:42.964
one of our videos with them

00:16:42.964 --> 00:16:46.700
to see how you might
go about explaining it.

00:16:46.700 --> 00:16:48.733
Chances are, after that
video, you will understand it

00:16:48.733 --> 00:16:51.290
quite a bit better than your own kid,

00:16:51.290 --> 00:16:53.920
and that might help you,
then, coach them a bit

00:16:53.920 --> 00:16:55.960
on the next few problems.

00:16:55.960 --> 00:16:58.641
If they seem just stuck
on one specific problem,

00:16:58.641 --> 00:17:02.220
again, we recommend they
take a look at the hints.

00:17:02.220 --> 00:17:04.910
They'll have multiple hints
available for each problem,

00:17:04.910 --> 00:17:08.120
so they can get just the
first bit of the solution,

00:17:08.120 --> 00:17:09.820
and maybe then, they'll have enough

00:17:09.820 --> 00:17:11.950
of what they need to
finish out the problem.

00:17:11.950 --> 00:17:14.550
Or they can click all the
way through to the answer.

00:17:15.520 --> 00:17:18.350
But there is another scenario
where you might anticipate

00:17:18.350 --> 00:17:21.250
just high levels of frustration.

00:17:21.250 --> 00:17:23.441
Maybe your kid gets a lot of math anxiety,

00:17:23.441 --> 00:17:27.060
or maybe they just have,
are already proving

00:17:27.060 --> 00:17:29.660
to have a tough time as
they try to transition

00:17:29.660 --> 00:17:32.105
to this really difficult
learning environment

00:17:32.105 --> 00:17:34.634
of learning from home.

00:17:34.634 --> 00:17:36.120
If you think that they are gonna have

00:17:36.120 --> 00:17:37.693
some of that general frustration,

00:17:37.693 --> 00:17:41.970
you'll see on the screen a
list of our different courses.

00:17:41.970 --> 00:17:44.780
You might decide that you're
gonna start a level earlier,

00:17:44.780 --> 00:17:48.300
build their confidence,
and as Vicki mentioned,

00:17:48.300 --> 00:17:51.340
these plans are designed from
3rd grade to algebra two.

00:17:51.340 --> 00:17:54.123
If your kids are more at a kindergarten,

00:17:54.123 --> 00:17:58.698
1st, 2nd grade enrollment, or math level,

00:17:58.698 --> 00:18:01.130
you might consider also checking out

00:18:01.130 --> 00:18:03.823
some of the math resources
from Khan Academy Kids.

00:18:04.871 --> 00:18:07.363
Back to you, Vicki.

00:18:13.228 --> 00:18:14.750
- Unmuting.

00:18:14.750 --> 00:18:16.804
How do we keep our kids motivated

00:18:16.804 --> 00:18:19.120
to follow through with
these plans week-to-week?

00:18:19.120 --> 00:18:23.710
Well, motivation for kids,
or for anybody, really,

00:18:23.710 --> 00:18:25.585
is about value, what value are you finding

00:18:25.585 --> 00:18:27.280
in the activity that you're doing?

00:18:27.280 --> 00:18:28.193
We're not motivated to do things

00:18:28.193 --> 00:18:30.377
that we don't think are valuable.

00:18:30.377 --> 00:18:32.240
It also can be about agency.

00:18:32.240 --> 00:18:34.303
We're sometimes not motivated to do things

00:18:34.303 --> 00:18:35.930
that we feel like we
don't have a choice about,

00:18:35.930 --> 00:18:38.380
so the key here, really, is to think about

00:18:38.380 --> 00:18:40.105
what do your kids value?

00:18:40.105 --> 00:18:41.310
What's gonna make it interesting
and exciting for them?

00:18:41.310 --> 00:18:42.920
And what's gonna make them feel like

00:18:42.920 --> 00:18:44.870
they have some choice and some ownership

00:18:44.870 --> 00:18:46.080
over the work that they're doing?

00:18:46.080 --> 00:18:49.268
On this slide, there's a
couple of suggestions here.

00:18:49.268 --> 00:18:52.670
You could take on a challenge
in parallel with them,

00:18:52.670 --> 00:18:54.790
so that the value comes
in spending time together

00:18:54.790 --> 00:18:57.270
with a parent who is
also modeling learning.

00:18:57.270 --> 00:18:58.780
You can use a simple reward system.

00:18:58.780 --> 00:19:00.124
You can give them some choices about

00:19:00.124 --> 00:19:02.425
when in the day they work on it,

00:19:02.425 --> 00:19:06.740
but for a full webinar on
motivation for your kiddos

00:19:06.740 --> 00:19:08.530
during this crisis time, we're gonna have

00:19:08.530 --> 00:19:11.619
a full webinar on that
next Wednesday, April 29th.

00:19:11.619 --> 00:19:15.400
We also are going to have
a webinar on motivating

00:19:15.400 --> 00:19:16.768
and managing multiple kiddos

00:19:16.768 --> 00:19:19.485
on different schedules on May 4th,

00:19:19.485 --> 00:19:23.950
and we had a webinar a few
weeks ago on structuring,

00:19:23.950 --> 00:19:25.070
it was called Structuring the Day

00:19:25.070 --> 00:19:26.760
for Kids Two Through Seven,

00:19:26.760 --> 00:19:27.920
because we did it with Khan Kids,

00:19:27.920 --> 00:19:29.542
but what's really communicated
there is structure

00:19:29.542 --> 00:19:32.609
and choice and connection and
keeping your kids motivated

00:19:32.609 --> 00:19:34.687
and kind of bought into learning

00:19:34.687 --> 00:19:39.687
by how you might schedule
some choice into their day.

00:19:39.930 --> 00:19:42.400
And so there are some other
resources there for you.

00:19:42.400 --> 00:19:45.294
But next Wednesday, motivation.

00:19:45.294 --> 00:19:47.880
And then I think a big question here

00:19:47.880 --> 00:19:50.150
with these learning plans
for me if I was a parent,

00:19:50.150 --> 00:19:52.038
I am a parent right now, but
if I was using this at home,

00:19:52.038 --> 00:19:57.038
would be that the first
week has already passed

00:19:58.292 --> 00:20:01.090
in the learning plans, or
maybe this doesn't work

00:20:01.090 --> 00:20:02.330
for my kiddo in some other way

00:20:02.330 --> 00:20:03.420
in the way that it's structured.

00:20:03.420 --> 00:20:06.896
How can I adapt it to meet
the needs of my own child?

00:20:06.896 --> 00:20:10.497
You might need to a different
number of weeks, for example.

00:20:10.497 --> 00:20:12.990
You might need to start
from an earlier grade

00:20:12.990 --> 00:20:15.190
in order to build
confidence if you anticipate

00:20:15.190 --> 00:20:16.488
that your kiddo is going to struggle.

00:20:16.488 --> 00:20:19.730
You might wanna revise the goal each week,

00:20:19.730 --> 00:20:22.050
especially if your child
earns a lot of points

00:20:22.050 --> 00:20:23.507
on that course challenge up front.

00:20:23.507 --> 00:20:25.833
The specific numbers that are week-by-week

00:20:25.833 --> 00:20:27.870
and those goals might not make sense,

00:20:27.870 --> 00:20:30.050
or your child might find
that they get to a week

00:20:30.050 --> 00:20:31.780
where they've already
earned most of the points

00:20:31.780 --> 00:20:33.310
in that unit from the course challenge,

00:20:33.310 --> 00:20:34.210
and so maybe they can work

00:20:34.210 --> 00:20:35.720
a little bit ahead to the next week.

00:20:35.720 --> 00:20:38.620
We really want you to take
what's here as just inspiration

00:20:38.620 --> 00:20:40.600
to be able to design a
plan that's going to work

00:20:40.600 --> 00:20:43.553
for your specific child and
your specific situation.

00:20:43.553 --> 00:20:46.910
Given that the first couple
of weeks have already passed

00:20:46.910 --> 00:20:47.793
that are in the learning plan,

00:20:47.793 --> 00:20:50.599
you might do something
like use the 12-week plan,

00:20:50.599 --> 00:20:53.394
but start it now, instead of
starting it three weeks ago,

00:20:53.394 --> 00:20:55.915
and it'll take you maybe into July.

00:20:55.915 --> 00:21:00.080
But really, we want you to just figure out

00:21:00.080 --> 00:21:03.650
a way to use this idea to build a plan

00:21:03.650 --> 00:21:06.850
with small goals for your
child that will work for you.

00:21:06.850 --> 00:21:09.649
And with that, I think we're
going to take some questions.

00:21:09.649 --> 00:21:13.072
I'm already seeing lots of
great questions in the dock.

00:21:13.072 --> 00:21:15.193
And I'll turn it over to Dan.

00:21:19.010 --> 00:21:19.980
- Hi, everyone.

00:21:19.980 --> 00:21:21.926
Dave, I wasn't sure if
you were gonna have a poll

00:21:21.926 --> 00:21:23.626
before we jump into the questions?

00:21:24.500 --> 00:21:25.950
- Oh, the poll, actually, we're gonna put

00:21:25.950 --> 00:21:27.924
as part of a survey
right after the webinar

00:21:27.924 --> 00:21:30.560
on actually your advice

00:21:30.560 --> 00:21:32.620
on how we might name these learning plans.

00:21:32.620 --> 00:21:34.500
If learning plan isn't the best thing,

00:21:34.500 --> 00:21:37.070
we'll get your thoughts on that after.

00:21:37.070 --> 00:21:39.080
- Perfect, well, thanks, Dave and Vicki.

00:21:39.080 --> 00:21:39.913
Hi, everyone, I'm Dan.

00:21:39.913 --> 00:21:43.840
I'll be moderating the live
QA portion of this session.

00:21:43.840 --> 00:21:46.444
Two things to do before we
move into the question portion.

00:21:46.444 --> 00:21:48.215
As Dave mentioned earlier,

00:21:48.215 --> 00:21:53.215
please download the presentation
in the handout section,

00:21:53.456 --> 00:21:55.900
and a recording of this,
as well as the handout,

00:21:55.900 --> 00:21:57.910
will be emailed to those who registered,

00:21:57.910 --> 00:22:00.870
and we'll post a recording
after this as well.

00:22:00.870 --> 00:22:04.470
And the recording and the
document covers everything

00:22:04.470 --> 00:22:06.620
from the learning plans, what they're for,

00:22:06.620 --> 00:22:07.951
some of the recommendations,

00:22:07.951 --> 00:22:11.380
as well as links to other
resources that we have available.

00:22:11.380 --> 00:22:13.440
And then the second thing
we wanna ask of you all

00:22:13.440 --> 00:22:15.638
is if you have any questions,
please add them now.

00:22:15.638 --> 00:22:18.215
I know there's already a
lot of really good questions

00:22:18.215 --> 00:22:20.880
in the question box, and I'll facilitate,

00:22:20.880 --> 00:22:23.020
and Vicki and Dave will do the hard work

00:22:23.020 --> 00:22:25.640
of actually answering the questions.

00:22:25.640 --> 00:22:27.440
We already have a couple, and Vicki,

00:22:27.440 --> 00:22:29.377
this one's probably more
appropriate for you.

00:22:29.377 --> 00:22:33.690
Ganesh asks, based on what
Sal states today on Axios.

00:22:33.690 --> 00:22:35.469
Sal was on Axios.

00:22:35.469 --> 00:22:39.736
Understanding that kids
potentially going through

00:22:39.736 --> 00:22:42.280
a five- to six-months learning loss,

00:22:42.280 --> 00:22:44.440
and forgetting another six months' worth

00:22:44.440 --> 00:22:46.367
of potential learning, kids may end up

00:22:46.367 --> 00:22:48.970
being behind a complete year,

00:22:48.970 --> 00:22:52.400
what are the practical steps
we can do to bridge the gap?

00:22:52.400 --> 00:22:53.690
And actually, that's why we created

00:22:53.690 --> 00:22:55.840
these learning plans in the first place.

00:22:55.840 --> 00:22:57.320
So, Vicki?

00:22:57.320 --> 00:22:59.510
- Yeah, this just, my heart hurts so much

00:22:59.510 --> 00:23:01.930
when I think about this.

00:23:01.930 --> 00:23:03.380
And I know districts
are working really hard

00:23:03.380 --> 00:23:05.030
to figure out what they're
gonna do in the fall

00:23:05.030 --> 00:23:07.007
to make sure that kids
aren't falling behind.

00:23:07.007 --> 00:23:10.370
what you can do as the
grown-up in the meantime

00:23:10.370 --> 00:23:15.217
is to keep your kid
practicing in gentle ways.

00:23:15.217 --> 00:23:19.227
Don't push math all the time
in a way that makes them go,

00:23:19.227 --> 00:23:20.440
"no, I don't want to."

00:23:20.440 --> 00:23:21.920
But just gently reminding them that math

00:23:21.920 --> 00:23:23.593
is part of their life,

00:23:23.593 --> 00:23:26.200
helping them do a little
bit of math every day.

00:23:26.200 --> 00:23:27.780
With my daughter, my daughter is six,

00:23:27.780 --> 00:23:29.463
and we have a lot of
mathematical conversations.

00:23:29.463 --> 00:23:31.740
When I'm doing something in the kitchen,

00:23:31.740 --> 00:23:33.448
or when we're picking up her
toys, we count they toys.

00:23:33.448 --> 00:23:37.560
We'll talk about math as
we're walking to the park.

00:23:37.560 --> 00:23:39.831
We'll maybe estimate, does that bush have,

00:23:39.831 --> 00:23:41.650
do you think it has more than 10 flowers

00:23:41.650 --> 00:23:43.170
or less than 10 flowers?

00:23:43.170 --> 00:23:45.850
And just trying to bring in casual ways

00:23:45.850 --> 00:23:47.330
of talking about math throughout the day

00:23:47.330 --> 00:23:48.780
in natural ways to your child,

00:23:48.780 --> 00:23:50.210
and then if you can help them,

00:23:50.210 --> 00:23:52.390
if they are willing to engage

00:23:52.390 --> 00:23:53.960
with some online math learning,
like what we're providing

00:23:53.960 --> 00:23:56.320
at Khan Academy, I think that's
really, really beneficial

00:23:56.320 --> 00:23:57.760
to really keep them moving forward

00:23:57.760 --> 00:23:59.339
with those on grade level skills.

00:23:59.339 --> 00:24:03.360
But continue really just bringing math in.

00:24:03.360 --> 00:24:05.258
- Perfect, and Dave, we
have a lot of questions

00:24:05.258 --> 00:24:06.980
around standards alignment.

00:24:06.980 --> 00:24:10.500
So from Cheryl, she's asking,
thank you for doing this.

00:24:10.500 --> 00:24:11.920
Are the lessons geared toward states

00:24:11.920 --> 00:24:13.122
with high math achievements,

00:24:13.122 --> 00:24:16.460
such as Massachusetts or
others such as California?

00:24:16.460 --> 00:24:17.773
And Jeanne asks a similar question.

00:24:17.773 --> 00:24:20.473
Are these based on
particular states' standards?

00:24:22.240 --> 00:24:23.800
- Yeah, great question.

00:24:23.800 --> 00:24:26.030
The 3rd through 8th grade,

00:24:26.030 --> 00:24:27.710
and then the high school curations,

00:24:27.710 --> 00:24:30.197
those are gonna be common core curations.

00:24:30.197 --> 00:24:35.197
The rigor of the questions
should be aligned

00:24:37.430 --> 00:24:41.040
with many of the states' summative exams,

00:24:41.040 --> 00:24:42.810
but you know, be the judge of that

00:24:42.810 --> 00:24:45.030
as you take a look yourself,

00:24:45.030 --> 00:24:47.330
and definitely consider
combining the resources

00:24:47.330 --> 00:24:49.270
we have with other
things that the district

00:24:49.270 --> 00:24:51.012
may be providing, other resources,

00:24:51.012 --> 00:24:54.078
especially some of the
open-ended responses

00:24:54.078 --> 00:24:55.740
that they might be getting

00:24:55.740 --> 00:24:57.843
good practice on from their district.

00:24:59.100 --> 00:25:00.380
- Perfect.

00:25:00.380 --> 00:25:01.610
Vicki, we're getting a lot of questions

00:25:01.610 --> 00:25:04.654
centered around how much
time a student will need

00:25:04.654 --> 00:25:07.740
for each of these units.

00:25:07.740 --> 00:25:10.450
So from Cindy asks, how much
time approximately per day

00:25:10.450 --> 00:25:12.750
or per week are the schedules based on?

00:25:12.750 --> 00:25:15.303
And Lisa asked, for
high school algebra one,

00:25:15.303 --> 00:25:19.090
roughly how much time should
a student dedicate to this

00:25:19.090 --> 00:25:21.770
to complete everything in the 20 weeks?

00:25:21.770 --> 00:25:23.150
- That's a great question.

00:25:23.150 --> 00:25:24.850
We designed them with the assumption

00:25:24.850 --> 00:25:27.400
that your student might spend
a similar amount of time

00:25:27.400 --> 00:25:28.430
to what they would spend in school,

00:25:28.430 --> 00:25:32.045
so about 45 minutes to an
hour a day, five days a week

00:25:32.045 --> 00:25:34.557
for that amount of time.

00:25:34.557 --> 00:25:36.910
And the amount of time that
it's gonna really require them

00:25:36.910 --> 00:25:38.930
to work through all the
work is gonna depend a lot

00:25:38.930 --> 00:25:40.640
on how much they already remember

00:25:40.640 --> 00:25:42.352
and test out of in the course challenge.

00:25:42.352 --> 00:25:46.370
Some students may move much more quickly.

00:25:46.370 --> 00:25:47.827
Some students may take a little more time.

00:25:47.827 --> 00:25:50.620
It also may vary week to week depending

00:25:50.620 --> 00:25:52.710
on how much they remember
in that particular unit,

00:25:52.710 --> 00:25:56.030
but that's the basic recommendation.

00:25:56.030 --> 00:25:57.591
- And kinda to piggyback off of that,

00:25:57.591 --> 00:25:59.967
Stephanie asks how do
we know whether to use

00:25:59.967 --> 00:26:03.533
the 12-week or the 20-week versions?

00:26:04.598 --> 00:26:06.750
- I mean, that's really just up to you

00:26:06.750 --> 00:26:08.350
and how much time you wanna invest

00:26:08.350 --> 00:26:10.954
and whether you want
your child to continue

00:26:10.954 --> 00:26:13.420
to practice math all the way
up until school starts again

00:26:13.420 --> 00:26:15.380
in the fall or only through when

00:26:15.380 --> 00:26:17.049
the regular school year might've ended.

00:26:17.049 --> 00:26:20.010
You also might be deciding
between the regular

00:26:20.010 --> 00:26:21.850
or on grade level learning plan

00:26:21.850 --> 00:26:23.048
and the foundational learning plan.

00:26:23.048 --> 00:26:26.661
And our thought is you might
do both at the same time.

00:26:26.661 --> 00:26:29.500
You might also choose the foundational one

00:26:29.500 --> 00:26:31.692
if your child is struggling
a little bit more in math,

00:26:31.692 --> 00:26:36.403
or for specific targeted
topics, you might dip into that

00:26:36.403 --> 00:26:38.200
to support some learning
that they're doing

00:26:38.200 --> 00:26:40.210
in the regular grade level.

00:26:40.210 --> 00:26:41.980
- And Stephanie's also
asking can she switch

00:26:41.980 --> 00:26:44.100
from one to the other, and
I think the answer to that

00:26:44.100 --> 00:26:45.800
is absolutely, test it out

00:26:45.800 --> 00:26:49.560
and see what's most comfortable
and appropriate for you.

00:26:49.560 --> 00:26:51.220
- Yeah.

00:26:51.220 --> 00:26:55.070
- Dave, Elaine asks my 7th
grader uses Khan Academy

00:26:55.070 --> 00:26:56.157
for math all the time.

00:26:56.157 --> 00:26:57.663
How is this different?

00:26:59.000 --> 00:27:00.780
- Well, the content should be similar.

00:27:00.780 --> 00:27:04.050
The student experience
on getting mastery points

00:27:04.050 --> 00:27:05.401
looks similar, as well,

00:27:05.401 --> 00:27:08.020
but two things might
feel different for them.

00:27:08.020 --> 00:27:10.374
One would be having a really clear goal,

00:27:10.374 --> 00:27:14.180
and second might be the
extra involvement from you,

00:27:14.180 --> 00:27:16.370
and those, I think, can
make a really big difference

00:27:16.370 --> 00:27:18.290
with the way they engage with math.

00:27:18.290 --> 00:27:19.987
But again, the actual content

00:27:19.987 --> 00:27:24.094
and the mastery learning plans, or system,

00:27:24.094 --> 00:27:27.403
is the same as in regular school year.

00:27:28.910 --> 00:27:30.530
- And a little bit related to that, Dave,

00:27:30.530 --> 00:27:32.830
Angela's asking if my child's
already doing Khan Academy

00:27:32.830 --> 00:27:35.704
with his class, would
you still recommend him

00:27:35.704 --> 00:27:37.403
doing the learning plan?

00:27:39.550 --> 00:27:41.184
- I would recommend having
a conversation with them

00:27:41.184 --> 00:27:43.079
and just seeing how they're feeling

00:27:43.079 --> 00:27:45.630
about clarity on what
they should be working on.

00:27:45.630 --> 00:27:48.547
If the answer comes back
a little tepid of like,

00:27:48.547 --> 00:27:51.490
oh, we're not really
receiving much to work on,

00:27:51.490 --> 00:27:53.700
because it is pretty
difficult for many districts

00:27:53.700 --> 00:27:56.650
to just get enough learning
resources out there

00:27:56.650 --> 00:27:59.241
in a short amount of time, then
this could supplement that.

00:27:59.241 --> 00:28:01.600
But if they seem to
already have a full plate

00:28:01.600 --> 00:28:04.424
of math practice coming from
their teacher and district,

00:28:04.424 --> 00:28:07.095
then that might be a signal
that these learning plans

00:28:07.095 --> 00:28:08.793
aren't necessary at this time.

00:28:09.916 --> 00:28:11.650
- And, Vicki, we have a question.

00:28:11.650 --> 00:28:14.427
We talked about grade level
and foundational things,

00:28:14.427 --> 00:28:16.670
but there's a question,
where would you start

00:28:16.670 --> 00:28:19.580
if your child's working
well above grade level?

00:28:19.580 --> 00:28:21.410
- Yeah, I would start
with the course challenge

00:28:21.410 --> 00:28:22.400
for the next grade level

00:28:22.400 --> 00:28:23.780
or the course challenge
for this grade level.

00:28:23.780 --> 00:28:27.090
That's a really good way for
your child to very quickly,

00:28:27.090 --> 00:28:28.580
in just about 30 or 45 minutes,

00:28:28.580 --> 00:28:30.201
get credit for the things
that they already know

00:28:30.201 --> 00:28:33.400
and make sure that they
don't create any gaps

00:28:33.400 --> 00:28:34.634
in things that they don't know.

00:28:34.634 --> 00:28:37.713
But that's a great way to
kind of accelerate progress.

00:28:38.629 --> 00:28:41.650
- Dave, we're getting
quite a few questions

00:28:41.650 --> 00:28:43.430
on how do I track my kid's progress?

00:28:43.430 --> 00:28:44.550
How should I think about it?

00:28:44.550 --> 00:28:47.383
So, Angela Degotti asks, how do you see

00:28:52.136 --> 00:28:54.827
how your child's doing in these skills?

00:28:55.860 --> 00:28:58.960
- Yeah, so we sort of touched
on this within the webinar,

00:28:58.960 --> 00:29:01.001
that the data available
on the parent dashboards

00:29:01.001 --> 00:29:04.020
is probably not gonna be as
detailed as you're looking for,

00:29:04.020 --> 00:29:05.610
since it was not created

00:29:05.610 --> 00:29:07.860
with the homeschool mentality in mind.

00:29:07.860 --> 00:29:09.520
That being said, you have two options.

00:29:09.520 --> 00:29:11.280
First option is you could actually

00:29:11.280 --> 00:29:13.885
create a teacher account
and enroll your kid

00:29:13.885 --> 00:29:17.420
as your own student, and then
you will get detailed data,

00:29:17.420 --> 00:29:18.700
and there's a lot of resources

00:29:18.700 --> 00:29:22.440
on our site for the teacher data reports.

00:29:22.440 --> 00:29:25.050
Or you could just have
them show you their screen

00:29:25.050 --> 00:29:26.590
and have a conversation about it,

00:29:26.590 --> 00:29:28.540
and that's our primary recommendation,

00:29:28.540 --> 00:29:29.801
'cause it doesn't require you to know

00:29:29.801 --> 00:29:32.253
all the ins and outs
of our teacher reports.

00:29:33.730 --> 00:29:35.320
- And I think we have time
for one more question,

00:29:35.320 --> 00:29:36.960
and Vicki, this one will be for you.

00:29:36.960 --> 00:29:38.130
What's the difference between

00:29:38.130 --> 00:29:40.580
the super ultra strong foundation plan

00:29:40.580 --> 00:29:43.463
versus the super fun plan,
and then related to that,

00:29:43.463 --> 00:29:46.760
is the 20-week just more
content, or is it the same,

00:29:46.760 --> 00:29:49.510
but just spread out over a
different number of weeks?

00:29:49.510 --> 00:29:53.430
- Yeah, the difference between the first,

00:29:53.430 --> 00:29:54.730
I can't remember how we structured them,

00:29:54.730 --> 00:29:57.770
or what we called them, whether
super fun or super great,

00:29:57.770 --> 00:30:00.117
but the first learning
plan, the grade level,

00:30:00.117 --> 00:30:01.730
3rd grade course, 6th grade course,

00:30:01.730 --> 00:30:03.760
is just the grade level
content that your student

00:30:03.760 --> 00:30:05.280
would've gotten at school this year.

00:30:05.280 --> 00:30:07.080
It's the content from the entire grade,

00:30:07.080 --> 00:30:08.663
not starting now, but the entire grade

00:30:08.663 --> 00:30:11.333
in that grade level course.

00:30:11.333 --> 00:30:14.540
The foundational one, the
one that says foundational

00:30:14.540 --> 00:30:16.890
and the name of it, is a related course,

00:30:16.890 --> 00:30:19.890
like early math, arithmetic,
that has more basic skills

00:30:19.890 --> 00:30:21.480
that probably have that grade level skill,

00:30:21.480 --> 00:30:23.280
but also stretch back a couple grades

00:30:23.280 --> 00:30:25.560
to bring in some core
skills to really build

00:30:25.560 --> 00:30:28.510
a strong foundation of earlier mathematics

00:30:28.510 --> 00:30:31.806
and math fundamentals, so
that's the difference there.

00:30:31.806 --> 00:30:36.660
I would say try to do both,

00:30:36.660 --> 00:30:38.139
or lean in to the grade level one,

00:30:38.139 --> 00:30:39.700
unless you're child's struggling,

00:30:39.700 --> 00:30:40.920
and then lean in to the foundational one.

00:30:40.920 --> 00:30:42.775
And the difference
between 20 and 12 weeks,

00:30:42.775 --> 00:30:44.802
they're both the whole course.

00:30:44.802 --> 00:30:48.250
In the 12-week, we pulled
out some of the units

00:30:48.250 --> 00:30:50.550
that are a little bit less critical.

00:30:50.550 --> 00:30:51.960
They're still, all math is important,

00:30:51.960 --> 00:30:53.950
but maybe the less critical
for that grade level,

00:30:53.950 --> 00:30:55.833
and put them as optional at the end.

00:30:55.833 --> 00:30:58.130
So the 12 weeks just really breaks up

00:30:58.130 --> 00:31:00.760
the most important key
skills from that grade,

00:31:00.760 --> 00:31:02.383
and then it says, if you have extra time,

00:31:02.383 --> 00:31:05.560
here's the other units that
you're gonna wanna work on.

00:31:05.560 --> 00:31:07.430
Whereas the 20 week just
embeds the whole thing

00:31:07.430 --> 00:31:10.110
in the order you would normally do it.

00:31:10.110 --> 00:31:12.120
- Perfect, so I think we're at time.

00:31:12.120 --> 00:31:13.860
Thank you, Dave, and thank you, Vicki,

00:31:13.860 --> 00:31:14.961
for sharing your expertise.

00:31:14.961 --> 00:31:17.250
And we wanted to thank
all of you, our audience,

00:31:17.250 --> 00:31:18.380
for taking the time out of

00:31:18.380 --> 00:31:20.095
your busy afternoons to be with us.

00:31:20.095 --> 00:31:22.700
We know you're extremely
busy and we appreciate you

00:31:22.700 --> 00:31:24.210
investing your time in this session.

00:31:24.210 --> 00:31:27.810
If you missed something or
you wanna go back and play,

00:31:27.810 --> 00:31:29.503
replay something, we know
this is a lot to cover

00:31:29.503 --> 00:31:32.117
in a short period of time, this recording,

00:31:32.117 --> 00:31:33.960
it will post it tomorrow.

00:31:33.960 --> 00:31:35.830
It'll be made available
for those who registered.

00:31:35.830 --> 00:31:37.690
It'll automatically be
sent to you in an email,

00:31:37.690 --> 00:31:40.005
along with the presentation.

00:31:40.005 --> 00:31:44.250
And we do have quite a few
other resources available

00:31:44.250 --> 00:31:46.331
at khanacademy.org, so if you go there,

00:31:46.331 --> 00:31:48.480
there's gonna be a blue ribbon at the top

00:31:48.480 --> 00:31:50.490
speaking specifically to remote learning,

00:31:50.490 --> 00:31:52.481
so you could always check that out.

00:31:52.481 --> 00:31:55.490
We're making updates quite
frequently, every day, in fact.

00:31:55.490 --> 00:31:58.700
So you can always go to khanacademy.org.

00:31:58.700 --> 00:32:00.680
And then before we sign
off, we wanna ask you

00:32:00.680 --> 00:32:03.260
to do us one more favor,
and please take the poll

00:32:03.260 --> 00:32:05.316
that pops up at the very
end of this webinar,

00:32:05.316 --> 00:32:07.220
and let us know two things.

00:32:07.220 --> 00:32:10.880
First, how could we make future iterations

00:32:10.880 --> 00:32:12.664
of this session even better for you all?

00:32:12.664 --> 00:32:15.230
And then what kind of sessions
would you like to see next?

00:32:15.230 --> 00:32:17.410
We've been asking this at
the end of each webinar,

00:32:17.410 --> 00:32:21.233
and it's helping us plan
what's most useful for you all.

00:32:21.233 --> 00:32:23.400
Please be sure to do that,

00:32:23.400 --> 00:32:25.030
and then Dave mentioned the poll,

00:32:25.030 --> 00:32:28.100
in terms of actually how to name these

00:32:28.100 --> 00:32:29.510
in a way that resonates with you all.

00:32:29.510 --> 00:32:31.517
So please fill that out for us.

00:32:31.517 --> 00:32:34.160
And in closing, we know you're juggling

00:32:34.160 --> 00:32:35.875
a lot as parents right now.

00:32:35.875 --> 00:32:39.560
This is uncharted territory,
you're asking to be a parent

00:32:39.560 --> 00:32:43.530
as well as a teacher, and we
wanna be here to support you.

00:32:43.530 --> 00:32:45.480
And one more thing is just we want,

00:32:45.480 --> 00:32:47.557
we here at Khan Academy want to remind you

00:32:47.557 --> 00:32:49.103
to be kind to yourselves.

00:32:49.103 --> 00:32:52.600
These schedules may appear to be a lot.

00:32:52.600 --> 00:32:53.830
They're really recommendations.

00:32:53.830 --> 00:32:58.560
Use them in a way that you feel
like it's most appropriate,

00:32:58.560 --> 00:33:01.137
and don't feel pressured
to complete all 20 weeks.

00:33:01.137 --> 00:33:03.581
You wanna try to get
through as much as you can

00:33:03.581 --> 00:33:06.010
in a way that feels right for you.

00:33:06.010 --> 00:33:09.040
And from all of us at Khan
Academy, thanks again,

00:33:09.040 --> 00:33:11.253
and thanks for joining us, and goodbye.


Gas mixtures and partial pressures

WEBVTT
Kind: captions
Language: en

00:00:00.420 --> 00:00:01.253
- [Instructor] In this video,

00:00:01.253 --> 00:00:03.710
we're going to introduce
ourselves to the idea

00:00:03.710 --> 00:00:08.480
of partial pressure due to ideal gases.

00:00:08.480 --> 00:00:10.150
And the way to think about it is

00:00:10.150 --> 00:00:13.360
imagine some type of a container,

00:00:13.360 --> 00:00:16.790
and you don't just have one
type of gas in that container.

00:00:16.790 --> 00:00:19.250
You have more than one type of gas.

00:00:19.250 --> 00:00:24.040
So let's say you have gas one
that is in this white color.

00:00:24.040 --> 00:00:25.820
And obviously, I'm not
drawing it to scale,

00:00:25.820 --> 00:00:29.360
and I'm just drawing those
gas molecules moving around.

00:00:29.360 --> 00:00:32.400
You have gas two in this yellow color.

00:00:32.400 --> 00:00:35.760
You have gas three in this blue color.

00:00:35.760 --> 00:00:38.670
It turns out that people
have been able to observe

00:00:38.670 --> 00:00:41.780
that the total pressure in this system

00:00:41.780 --> 00:00:43.290
and you could imagine that's being exerted

00:00:43.290 --> 00:00:44.360
on the inside of the wall,

00:00:44.360 --> 00:00:45.850
or if you put anything in this container,

00:00:45.850 --> 00:00:48.590
the pressure, the force per
area that would be exerted

00:00:48.590 --> 00:00:51.390
on that thing is equal to the sum

00:00:51.390 --> 00:00:55.280
of the pressures contributed
from each of these gases

00:00:55.280 --> 00:00:58.770
or the pressure that each
gas would exert on its own.

00:00:58.770 --> 00:01:01.260
So this is going to be equal to

00:01:01.260 --> 00:01:03.910
the partial pressure due to gas one

00:01:03.910 --> 00:01:07.200
plus the partial pressure due to gas two

00:01:07.200 --> 00:01:11.530
plus the partial pressure
due to gas three.

00:01:11.530 --> 00:01:13.750
And this makes sense mathematically

00:01:13.750 --> 00:01:17.110
from the ideal gas law
that we have seen before.

00:01:17.110 --> 00:01:18.900
Remember, the ideal gas law tells us

00:01:18.900 --> 00:01:22.580
that pressure times volume is
equal to the number of moles

00:01:22.580 --> 00:01:27.140
times the ideal gas constant
times the temperature.

00:01:27.140 --> 00:01:29.380
And so if you were to
solve for pressure here,

00:01:29.380 --> 00:01:30.790
just divide both sides by volume.

00:01:30.790 --> 00:01:32.540
You'd get pressure is equal to nR

00:01:33.900 --> 00:01:36.260
times T over volume.

00:01:36.260 --> 00:01:40.160
And so we can express both
sides of this equation that way.

00:01:40.160 --> 00:01:44.350
Our total pressure, that would
be our total number of moles.

00:01:44.350 --> 00:01:47.040
So let me write it this way, n total

00:01:47.040 --> 00:01:48.900
times the ideal gas constant

00:01:48.900 --> 00:01:51.130
times our temperature in kelvin

00:01:51.130 --> 00:01:53.580
divided by the volume of our container.

00:01:53.580 --> 00:01:55.910
And that's going to be equal to,

00:01:55.910 --> 00:01:58.290
so the pressure due to gas one,

00:01:58.290 --> 00:02:00.770
that's going to be the
number of moles of gas one,

00:02:00.770 --> 00:02:04.620
times the ideal gas constant
times the temperature,

00:02:04.620 --> 00:02:06.730
the temperature is not going
to be different for each gas,

00:02:06.730 --> 00:02:09.020
we're assuming they're all
in the same environment,

00:02:09.020 --> 00:02:10.710
divided by the volume.

00:02:10.710 --> 00:02:12.530
And once again, the volume
is going to be the same.

00:02:12.530 --> 00:02:14.910
They're all in the same
container in this situation.

00:02:14.910 --> 00:02:19.460
And then we would add that to
the number of moles of gas two

00:02:19.460 --> 00:02:21.930
times the ideal gas constant,
which once again is going

00:02:21.930 --> 00:02:23.680
to be the same for all of the gases,

00:02:23.680 --> 00:02:26.270
times the temperature
divided by the volume.

00:02:26.270 --> 00:02:27.920
And then to that,

00:02:27.920 --> 00:02:30.150
we could add the number
of moles of gas three

00:02:30.150 --> 00:02:31.940
times the ideal gas constant

00:02:31.940 --> 00:02:35.030
times the temperature
divided by the volume.

00:02:35.030 --> 00:02:37.200
Now, I just happen to
have three gases here,

00:02:37.200 --> 00:02:39.450
but you could clearly keep going

00:02:39.450 --> 00:02:43.460
and keep adding more
gases into this container.

00:02:43.460 --> 00:02:45.640
But when you look at it
mathematically like this,

00:02:45.640 --> 00:02:48.450
you can see that the right-hand side,

00:02:48.450 --> 00:02:51.760
we can factor out the RT over V.

00:02:51.760 --> 00:02:55.800
And if you do that, you
are going to get n one

00:02:55.800 --> 00:02:58.530
plus n two

00:02:58.530 --> 00:03:00.963
plus n three,

00:03:02.010 --> 00:03:05.930
let me close those parentheses, times RT,

00:03:05.930 --> 00:03:08.230
RT over V.

00:03:08.230 --> 00:03:11.290
And this right over here
is the exact same thing

00:03:11.290 --> 00:03:13.130
as our total number of moles.

00:03:13.130 --> 00:03:16.000
If you say the number of moles of gas one

00:03:16.000 --> 00:03:17.770
plus the number of moles of gas two

00:03:17.770 --> 00:03:19.340
plus the number of moles of gas three,

00:03:19.340 --> 00:03:21.590
that's going to give you
the total number of moles

00:03:21.590 --> 00:03:24.450
of gas that you have in the container.

00:03:24.450 --> 00:03:28.600
So this makes sense
mathematically and logically.

00:03:28.600 --> 00:03:30.850
And we can use these mathematical ideas

00:03:30.850 --> 00:03:32.170
to answer other questions

00:03:32.170 --> 00:03:34.670
or to come up with other
ways of thinking about it.

00:03:34.670 --> 00:03:37.860
For example, let's say that we knew

00:03:37.860 --> 00:03:41.340
that the total pressure in our container

00:03:41.340 --> 00:03:43.310
due to all of the gases

00:03:43.310 --> 00:03:46.350
is four atmospheres.

00:03:46.350 --> 00:03:50.870
And let's say we know that
the total number of moles

00:03:50.870 --> 00:03:54.640
in the container is equal to

00:03:54.640 --> 00:03:57.020
eight moles.

00:03:57.020 --> 00:03:59.320
And let's say we know

00:03:59.320 --> 00:04:02.640
that the number of moles of gas three

00:04:02.640 --> 00:04:05.610
is equal to two moles.

00:04:05.610 --> 00:04:07.590
Can we use this information to figure out

00:04:07.590 --> 00:04:11.880
what is going to be the partial
pressure due to gas three?

00:04:11.880 --> 00:04:14.860
Pause this video, and
try to think about that.

00:04:14.860 --> 00:04:17.190
Well, one way you could think about it is

00:04:17.190 --> 00:04:20.580
the partial pressure due to gas three

00:04:20.580 --> 00:04:23.183
over the total pressure,

00:04:24.150 --> 00:04:28.003
over the total pressure
is going to be equal to,

00:04:29.140 --> 00:04:30.820
if we just look at this
piece right over here,

00:04:30.820 --> 00:04:31.790
it's going to be this.

00:04:31.790 --> 00:04:35.380
It's going to be the number
of moles of gas three

00:04:35.380 --> 00:04:36.900
times the ideal gas constant

00:04:36.900 --> 00:04:39.930
times the temperature
divided by the volume.

00:04:39.930 --> 00:04:42.600
And then the total pressure,

00:04:42.600 --> 00:04:45.010
well, that's just going
to be this expression.

00:04:45.010 --> 00:04:48.500
So the total number of moles
times the ideal gas constant

00:04:48.500 --> 00:04:49.780
times that same temperature,

00:04:49.780 --> 00:04:51.350
'cause they're all in
the same environment,

00:04:51.350 --> 00:04:52.820
divided by that same volume.

00:04:52.820 --> 00:04:54.030
They're in the same container.

00:04:54.030 --> 00:04:57.170
And you can see very clearly
that the RT over V is

00:04:57.170 --> 00:04:58.590
in the numerator and the denominator,

00:04:58.590 --> 00:05:00.540
so they're going to cancel out.

00:05:00.540 --> 00:05:02.890
And we get this idea that the,

00:05:02.890 --> 00:05:03.980
I'll write it down here,

00:05:03.980 --> 00:05:08.070
the partial pressure due to gas three over

00:05:08.070 --> 00:05:09.250
the total pressure

00:05:10.760 --> 00:05:12.290
is equal to

00:05:13.800 --> 00:05:17.640
the number of moles of gas three

00:05:17.640 --> 00:05:20.736
divided by the total,

00:05:20.736 --> 00:05:22.230
total number of moles.

00:05:22.230 --> 00:05:24.560
And this quantity right over here,

00:05:24.560 --> 00:05:27.420
this is known as the mole fraction.

00:05:27.420 --> 00:05:28.430
Let me just write that down.

00:05:28.430 --> 00:05:29.680
It's a useful concept.

00:05:29.680 --> 00:05:32.850
And you can see the mole
fraction can help you figure out

00:05:32.850 --> 00:05:34.620
what the partial pressure is going to be.

00:05:34.620 --> 00:05:38.100
So for this example, if we
just substitute the numbers,

00:05:38.100 --> 00:05:42.140
we know that the total pressure is four.

00:05:42.140 --> 00:05:45.600
We know that the total
number of moles is eight.

00:05:45.600 --> 00:05:46.800
We know that the moles,

00:05:46.800 --> 00:05:50.660
the number of moles of gas three is two.

00:05:50.660 --> 00:05:51.890
And then we can just solve.

00:05:51.890 --> 00:05:54.260
We get, let me just do
it, write it over here,

00:05:54.260 --> 00:05:56.460
I'll write it in one color,

00:05:56.460 --> 00:05:59.970
that the partial pressure
due to gas three over four

00:05:59.970 --> 00:06:02.930
is equal to two over
eight, is equal to 1/4.

00:06:02.930 --> 00:06:04.640
And so you can just pattern match this,

00:06:04.640 --> 00:06:07.990
or you can multiply both sides by four

00:06:07.990 --> 00:06:12.200
to figure out that the partial
pressure due to gas three

00:06:12.200 --> 00:06:14.730
is going to be one.

00:06:14.730 --> 00:06:17.090
And since we were dealing
with units of atmosphere

00:06:17.090 --> 00:06:20.330
for the total pressure, this
is going to be one atmosphere.

00:06:20.330 --> 00:06:21.603
And we'd be done.


The ideal gas law (PV = nRT)

WEBVTT
Kind: captions
Language: en

00:00:00.160 --> 00:00:01.330
- [Instructor] In this
video we're gonna talk

00:00:01.330 --> 00:00:05.070
about ideal gasses and how we can describe

00:00:05.070 --> 00:00:06.760
what's going on with them.

00:00:06.760 --> 00:00:08.460
So the first question you
might be wondering is,

00:00:08.460 --> 00:00:10.850
what is an ideal gas?

00:00:10.850 --> 00:00:13.620
And it really is a bit of
a theoretical construct

00:00:13.620 --> 00:00:16.590
that helps us describe
a lot of what's going on

00:00:16.590 --> 00:00:18.280
in the gas world, or at least close

00:00:18.280 --> 00:00:20.470
to what's going on in the gas world.

00:00:20.470 --> 00:00:22.710
So in an ideal gas, we imagined

00:00:22.710 --> 00:00:27.160
that the individual particles
of the gas don't interact.

00:00:27.160 --> 00:00:31.913
So particles, particles don't interact.

00:00:33.750 --> 00:00:36.260
And obviously we know
that's not generally true.

00:00:36.260 --> 00:00:39.060
There's generally some
light intermolecular forces

00:00:39.060 --> 00:00:40.690
as they get close to each other

00:00:40.690 --> 00:00:42.560
or as they pass by each other

00:00:42.560 --> 00:00:44.380
or if they collide into each other.

00:00:44.380 --> 00:00:47.100
But for the sake of what we're
going to study in this video,

00:00:47.100 --> 00:00:49.230
we'll assume that they don't interact.

00:00:49.230 --> 00:00:50.580
And we'll also assume

00:00:50.580 --> 00:00:53.920
that the particles don't
take up any volume.

00:00:53.920 --> 00:00:58.600
Don't take up volume.

00:00:58.600 --> 00:01:00.630
Now, we know that that isn't exactly true,

00:01:00.630 --> 00:01:04.180
that individual molecules
of course do take up volume.

00:01:04.180 --> 00:01:06.010
But this is a reasonable assumption,

00:01:06.010 --> 00:01:07.740
because generally speaking, it might be

00:01:07.740 --> 00:01:11.030
a very, very infinitesimally
small fraction

00:01:11.030 --> 00:01:13.580
of the total volume of the space

00:01:13.580 --> 00:01:15.250
that they are bouncing around in.

00:01:15.250 --> 00:01:17.180
And so these are the
two assumptions we make

00:01:17.180 --> 00:01:18.810
when we talk about ideal gasses.

00:01:18.810 --> 00:01:21.340
That's why we're using the word ideal.

00:01:21.340 --> 00:01:24.650
In future videos we'll talk
about non-ideal behavior.

00:01:24.650 --> 00:01:26.560
But it allows us to make
some simplifications

00:01:26.560 --> 00:01:29.430
that approximate a lot of the world.

00:01:29.430 --> 00:01:32.870
So let's think about how we
can describe ideal gasses.

00:01:32.870 --> 00:01:34.840
We can think about the volume

00:01:34.840 --> 00:01:37.630
of the container that they are in.

00:01:37.630 --> 00:01:40.920
We could imagine the pressure
that they would exert

00:01:40.920 --> 00:01:43.570
on say the inside of the container.

00:01:43.570 --> 00:01:44.950
That's how I visualize it.

00:01:44.950 --> 00:01:46.990
Although, that pressure would be the same

00:01:46.990 --> 00:01:49.940
at any point inside of the container.

00:01:49.940 --> 00:01:51.360
We can think about the temperature.

00:01:51.360 --> 00:01:52.920
And we wanna do it in absolute scale,

00:01:52.920 --> 00:01:55.970
so we generally measure
temperature in kelvin.

00:01:55.970 --> 00:01:57.240
And then we could also think

00:01:57.240 --> 00:02:01.090
about just how much of that gas we have.

00:02:01.090 --> 00:02:04.500
And we can measure that in
terms of number of moles.

00:02:04.500 --> 00:02:07.100
And so that's what this lowercase n is.

00:02:07.100 --> 00:02:09.290
So let's think about how these four things

00:02:09.290 --> 00:02:11.190
can relate to each other.

00:02:11.190 --> 00:02:14.050
So let's just always put
volume on the left-hand side.

00:02:14.050 --> 00:02:17.190
How does volume relate to pressure?

00:02:17.190 --> 00:02:20.790
Well, what I imagine is, if
I have a balloon like this

00:02:20.790 --> 00:02:23.990
and I have some gas in the balloon,

00:02:23.990 --> 00:02:26.740
if I try to decrease the volume

00:02:26.740 --> 00:02:28.640
by making it a smaller balloon

00:02:28.640 --> 00:02:30.470
without letting out any other air

00:02:30.470 --> 00:02:32.200
or without changing the temperature,

00:02:32.200 --> 00:02:34.690
so I'm not changing T and n,

00:02:34.690 --> 00:02:36.690
what's going to happen to the pressure?

00:02:36.690 --> 00:02:39.640
Well, that gas is going
to, per square inch

00:02:39.640 --> 00:02:42.200
or per square area, exert
more and more force.

00:02:42.200 --> 00:02:46.590
It gets harder and harder for
me to squeeze that balloon.

00:02:46.590 --> 00:02:49.730
So as volume goes down, pressure goes up.

00:02:49.730 --> 00:02:52.720
Or likewise, if I were to
make the container bigger,

00:02:52.720 --> 00:02:55.020
not changing, once again, the temperature

00:02:55.020 --> 00:02:58.390
or the number of moles I
have inside of the container,

00:02:58.390 --> 00:03:00.630
it's going to lower the pressure.

00:03:00.630 --> 00:03:02.740
So it looks like volume and pressure move

00:03:02.740 --> 00:03:04.430
inversely with each other.

00:03:04.430 --> 00:03:07.770
So what we could say is
that volume is proportional

00:03:07.770 --> 00:03:12.770
to one over pressure,
the inverse of pressure.

00:03:13.260 --> 00:03:14.950
Or you could say that
pressure is proportional

00:03:14.950 --> 00:03:16.580
to the inverse of volume.

00:03:16.580 --> 00:03:18.430
This just means proportional to.

00:03:18.430 --> 00:03:19.990
Which means that volume would be equal

00:03:19.990 --> 00:03:24.620
to some constant divided
by pressure in this case.

00:03:24.620 --> 00:03:28.443
Now how does volume relate to temperature?

00:03:29.430 --> 00:03:31.680
Well, if I start with my balloon example,

00:03:31.680 --> 00:03:35.690
and you could run this example
if you don't believe me,

00:03:35.690 --> 00:03:38.150
if you take a balloon and you were

00:03:38.150 --> 00:03:41.120
to blow it up at room temperature,

00:03:41.120 --> 00:03:43.500
and then if you were to
put it into the fridge,

00:03:43.500 --> 00:03:45.200
you should see what happens.

00:03:45.200 --> 00:03:46.530
It's going to shrink.

00:03:46.530 --> 00:03:49.020
And you might say, "Why is it shrinking?"

00:03:49.020 --> 00:03:50.180
Well, you could imagine

00:03:50.180 --> 00:03:52.370
that the particles inside the balloon are

00:03:52.370 --> 00:03:54.320
a little less vigorous at that point.

00:03:54.320 --> 00:03:57.350
They have lower individual
kinetic energies.

00:03:57.350 --> 00:04:00.400
And so in order for them
to exert the same pressure

00:04:00.400 --> 00:04:03.050
to offset atmospheric
pressure on the outside,

00:04:03.050 --> 00:04:06.290
you are going to have a lower volume.

00:04:06.290 --> 00:04:11.290
And so volume you could say is
proportional to temperature.

00:04:11.500 --> 00:04:16.310
Now how does volume
compare to number of moles?

00:04:16.310 --> 00:04:17.143
Well, think about it.

00:04:17.143 --> 00:04:19.070
If you blow air into a balloon,

00:04:19.070 --> 00:04:21.330
you're putting more
moles into that balloon.

00:04:21.330 --> 00:04:24.260
And holding pressure and
temperature constant,

00:04:24.260 --> 00:04:27.120
you are going to increase the volume.

00:04:27.120 --> 00:04:30.500
So volume is proportional
to the number of moles.

00:04:30.500 --> 00:04:31.850
If you were to take air out,

00:04:31.850 --> 00:04:33.880
you're also going to decrease the volume,

00:04:33.880 --> 00:04:36.920
keeping pressure and temperature constant.

00:04:36.920 --> 00:04:39.290
So we can use these three relationships,

00:04:39.290 --> 00:04:40.520
and these are actually known as,

00:04:40.520 --> 00:04:42.360
this first one is known as Boyle's law,

00:04:42.360 --> 00:04:45.290
this is Charles' law,
this is Avogadro's law.

00:04:45.290 --> 00:04:49.100
But you can combine them to
realize that volume is going

00:04:49.100 --> 00:04:53.910
to be proportional to
the number of moles times

00:04:53.910 --> 00:04:58.560
the temperature divided by the pressure.

00:04:58.560 --> 00:05:01.840
Divided by the pressure.

00:05:01.840 --> 00:05:04.150
Or another way to say it is, you could say

00:05:04.150 --> 00:05:08.410
that volume is going to
be equal to some constant,

00:05:08.410 --> 00:05:10.860
that's what proportionality
is just talking about,

00:05:10.860 --> 00:05:14.600
is gonna be equal to some
constant, let's call it R,

00:05:14.600 --> 00:05:15.947
times all of this business,

00:05:15.947 --> 00:05:20.947
RnT over P.

00:05:21.320 --> 00:05:23.210
Over P.

00:05:23.210 --> 00:05:25.130
Or another way to think about it is

00:05:25.130 --> 00:05:28.800
we can multiply both sides by P.

00:05:28.800 --> 00:05:29.820
And what will you get?

00:05:29.820 --> 00:05:34.700
We will get P times V,
this might be looking

00:05:34.700 --> 00:05:37.230
somewhat familiar to some of you, is equal

00:05:37.230 --> 00:05:39.720
to, and I'll just change
the order right over here,

00:05:39.720 --> 00:05:43.400
n, which is the number of moles,

00:05:43.400 --> 00:05:48.300
times some constant times T,

00:05:48.300 --> 00:05:50.840
our temperature measured in kelvin.

00:05:50.840 --> 00:05:53.690
And this relationship right
over here, PV is equal

00:05:53.690 --> 00:05:56.520
to nRT, is one of the most
useful things in chemistry.

00:05:56.520 --> 00:05:59.040
And it's known as the ideal gas law.

00:05:59.040 --> 00:06:00.810
And in future videos
we're going to apply it

00:06:00.810 --> 00:06:03.640
over and over again to
see how useful it is.

00:06:03.640 --> 00:06:05.477
Now, one question you
might be wondering is,

00:06:05.477 --> 00:06:06.950
"What is this constant?"

00:06:06.950 --> 00:06:08.910
It's known as the ideal gas constant.

00:06:08.910 --> 00:06:11.380
And you can look it up, but
it's going to be dependent

00:06:11.380 --> 00:06:13.320
on what units you use for a pressure

00:06:13.320 --> 00:06:15.720
or volume and temperature.

00:06:15.720 --> 00:06:18.283
And we will see that in future videos.


London dispersion forces

WEBVTT
Kind: captions
Language: en

00:00:00.270 --> 00:00:01.560
- [Instructor] What we're
going to do in this video

00:00:01.560 --> 00:00:05.280
is start talking about
forces that exist between

00:00:05.280 --> 00:00:08.840
even neutral atoms, or neutral molecules.

00:00:08.840 --> 00:00:11.100
The first of these intermolecular forces

00:00:11.100 --> 00:00:15.350
we will talk about are
London dispersion forces.

00:00:15.350 --> 00:00:17.450
So it sounds very fancy but it's actually

00:00:17.450 --> 00:00:20.740
a pretty interesting and
almost intuitive phenomenon.

00:00:20.740 --> 00:00:22.830
So we are used to thinking about atoms,

00:00:22.830 --> 00:00:24.430
and let's just say we have a neutral atom.

00:00:24.430 --> 00:00:26.920
So it has the same number
of proton and electrons.

00:00:26.920 --> 00:00:29.336
And so those are all the protons

00:00:29.336 --> 00:00:31.810
and the neutrons in the nucleus.

00:00:31.810 --> 00:00:34.600
And then it'll have a cloud of electrons.

00:00:34.600 --> 00:00:36.640
So I'm just imagining all these electrons

00:00:36.640 --> 00:00:37.680
kinda jumping around.

00:00:37.680 --> 00:00:39.880
That's how I'm going to represent it.

00:00:39.880 --> 00:00:43.090
And let's imagine, and this is
definitely not drawn to scale

00:00:43.090 --> 00:00:45.960
the nucleus would actually
be much smaller if it was.

00:00:45.960 --> 00:00:47.967
But let's say that
there's an adjacent atom

00:00:47.967 --> 00:00:50.080
right over here and it's also neutral.

00:00:50.080 --> 00:00:51.600
Maybe it's the same type of atom.

00:00:51.600 --> 00:00:53.910
It could be different, but
we're gonna say it's neutral.

00:00:53.910 --> 00:00:56.970
And it also has an electron cloud.

00:00:56.970 --> 00:01:00.160
And so if these are
both neutral in charge,

00:01:00.160 --> 00:01:02.660
how would they be attracted to each other?

00:01:02.660 --> 00:01:05.810
And that's what London dispersion
forces actually explain.

00:01:05.810 --> 00:01:09.220
Because we have observed
that even neutral atoms

00:01:09.220 --> 00:01:12.920
and neutral molecules can
get attracted to each other.

00:01:12.920 --> 00:01:15.180
And the way to think about it is,

00:01:15.180 --> 00:01:18.830
electrons are constantly jumping
around, probabilistically.

00:01:18.830 --> 00:01:21.440
They're in this probability density cloud

00:01:21.440 --> 00:01:24.200
where an electron could be
anywhere at any given moment.

00:01:24.200 --> 00:01:26.970
But they're not always going
to be evenly distributed.

00:01:26.970 --> 00:01:29.160
You can imagine that there is a moment

00:01:29.160 --> 00:01:32.880
where that left atom might look
like this, just for moment,

00:01:32.880 --> 00:01:35.930
where maybe slightly more of the electrons

00:01:35.930 --> 00:01:39.520
are spending time on the
left side of the atom

00:01:39.520 --> 00:01:41.090
than on the right side.

00:01:41.090 --> 00:01:43.290
So maybe it looks something like that.

00:01:43.290 --> 00:01:45.270
And so for that brief moment,

00:01:45.270 --> 00:01:47.450
you have a partial negative charge,

00:01:47.450 --> 00:01:50.340
this is the Greek letter
delta, lowercase delta,

00:01:50.340 --> 00:01:53.210
which is used to denote partial charge.

00:01:53.210 --> 00:01:57.340
And on this side, you might
have a partial positive charge.

00:01:57.340 --> 00:01:59.320
Because remember when it
was evenly distributed

00:01:59.320 --> 00:02:01.160
the negative charge was offset by

00:02:01.160 --> 00:02:03.100
the positive charge of the nucleus.

00:02:03.100 --> 00:02:04.480
But here on the right side,

00:02:04.480 --> 00:02:05.810
because there's fewer electrons here,

00:02:05.810 --> 00:02:07.040
maybe you have a partial positive.

00:02:07.040 --> 00:02:09.570
On the left side where
most of the electrons are

00:02:09.570 --> 00:02:11.730
in that moment, partial negative.

00:02:11.730 --> 00:02:16.400
Now what might this induce
in the neighboring atom?

00:02:16.400 --> 00:02:17.233
Think about that.

00:02:17.233 --> 00:02:18.999
Pause the video and think about

00:02:18.999 --> 00:02:21.760
what might happen in the
neighboring atom then.

00:02:21.760 --> 00:02:24.870
Well we know that like
charges repel each other

00:02:24.870 --> 00:02:27.550
and opposite charges attract each other.

00:02:27.550 --> 00:02:29.910
So if we have a partial positive charge

00:02:29.910 --> 00:02:32.760
out here on the right
side of this left atom,

00:02:32.760 --> 00:02:35.450
well then the negative electrons might be

00:02:35.450 --> 00:02:37.990
attracted to it in this right atom.

00:02:37.990 --> 00:02:39.680
So these electrons here might actually

00:02:39.680 --> 00:02:42.530
be pulled a little bit to the left.

00:02:42.530 --> 00:02:45.080
So they might be pulled
a little bit to the left.

00:02:45.080 --> 00:02:49.843
And so that will induce
what is called a dipole.

00:02:51.362 --> 00:02:52.810
So now you'll have a
partial negative charge

00:02:52.810 --> 00:02:54.590
on the left side of this atom,

00:02:54.590 --> 00:02:58.500
and then a partial positive
charge on the right side of it.

00:02:58.500 --> 00:03:01.610
And we already had a
randomly occurring dipole

00:03:01.610 --> 00:03:03.620
on the left hand side,
but then that would have

00:03:03.620 --> 00:03:06.000
induce a dipole on the right hand side.

00:03:06.000 --> 00:03:07.110
A dipole is just when you have

00:03:07.110 --> 00:03:09.530
the separation of charge,
where you have your

00:03:09.530 --> 00:03:12.560
positive and negative charges
at two different parts

00:03:12.560 --> 00:03:16.370
of a molecule or an
atom, or really anything.

00:03:16.370 --> 00:03:18.944
But in this world, then all of
a sudden these two characters

00:03:18.944 --> 00:03:22.050
are going to be attracted to each other.

00:03:22.050 --> 00:03:24.770
Or the atoms are going to
be attracted to each other.

00:03:24.770 --> 00:03:27.410
And this attraction that happens due to

00:03:27.410 --> 00:03:30.950
induced dipoles, that is exactly what

00:03:30.950 --> 00:03:34.480
London dispersion forces is all about.

00:03:34.480 --> 00:03:36.450
You can actually call
London dispersion forces

00:03:36.450 --> 00:03:39.600
as induced dipole, induced dipole forces.

00:03:39.600 --> 00:03:41.410
They become attracted to each other

00:03:41.410 --> 00:03:43.780
because of what could
start out as a temporary

00:03:43.780 --> 00:03:46.130
imbalance of electrons,
but then it induces

00:03:46.130 --> 00:03:48.750
a dipole in the other atom,
or the other molecule,

00:03:48.750 --> 00:03:50.390
and then they get attracted.

00:03:50.390 --> 00:03:52.300
So the next question you might ask is,

00:03:52.300 --> 00:03:54.250
how strong can these forces get?

00:03:54.250 --> 00:03:58.613
And that's all about a
notion of polarizability.

00:04:00.140 --> 00:04:03.920
How easy is it to polarize
an atom or molecule?

00:04:03.920 --> 00:04:08.520
And generally speaking, the
more electrons you have,

00:04:08.520 --> 00:04:11.055
so the larger the electron cloud,

00:04:11.055 --> 00:04:15.810
larger electron cloud,

00:04:15.810 --> 00:04:20.290
which is usually
associated with molar mass.

00:04:20.290 --> 00:04:22.283
So usually molar mass,

00:04:23.450 --> 00:04:26.510
then the higher polarizability
you're gonna have.

00:04:26.510 --> 00:04:29.569
You're just gonna have more
electrons to play around with.

00:04:29.569 --> 00:04:31.142
If this was a Helium atom which has

00:04:31.142 --> 00:04:33.510
a relatively small electron cloud,

00:04:33.510 --> 00:04:36.000
you couldn't have a significant imbalance.

00:04:36.000 --> 00:04:39.460
At most you might have
two electrons on one side,

00:04:39.460 --> 00:04:41.610
which would cause some imbalance.

00:04:41.610 --> 00:04:44.660
But on the other hand,
imagine a much larger atom,

00:04:44.660 --> 00:04:46.730
or a much larger molecule.

00:04:46.730 --> 00:04:49.112
You could have much more
significant imbalances.

00:04:49.112 --> 00:04:52.080
Three, four, five, fifty electrons.

00:04:52.080 --> 00:04:54.680
And that would create a
stronger temporary dipole,

00:04:54.680 --> 00:04:58.130
which would then induce a
stronger dipole in the neighbor.

00:04:58.130 --> 00:05:00.320
That could domino through

00:05:00.320 --> 00:05:02.630
the entire sample of that molecule.

00:05:02.630 --> 00:05:05.910
So for example, if you were to compare

00:05:05.910 --> 00:05:08.640
some noble gases to each other.

00:05:08.640 --> 00:05:10.620
So we can look at the noble gases

00:05:10.620 --> 00:05:12.380
here on the right hand side.

00:05:12.380 --> 00:05:15.410
If you were to compare the
London dispersion forces

00:05:15.410 --> 00:05:18.620
between, say Helium and Argon,

00:05:18.620 --> 00:05:20.420
which one do you think would have higher

00:05:20.420 --> 00:05:21.750
London dispersion forces?

00:05:21.750 --> 00:05:23.580
A bunch of Helium atoms
next to each other,

00:05:23.580 --> 00:05:26.560
or a bunch of Argon
atoms next to each other?

00:05:26.560 --> 00:05:30.570
Well the Argon atoms have
a larger electron cloud.

00:05:30.570 --> 00:05:34.200
So they have higher polarizability.

00:05:34.200 --> 00:05:36.020
And so you're going to have higher

00:05:36.020 --> 00:05:37.830
London dispersion forces.

00:05:37.830 --> 00:05:40.720
And you can actually see
that in their boiling points.

00:05:40.720 --> 00:05:45.720
For example, the boiling
point of Helium is quite low.

00:05:47.770 --> 00:05:52.770
It is negative 268.9 degrees Celsius.

00:05:53.040 --> 00:05:55.660
While the boiling point for Argon,

00:05:55.660 --> 00:05:58.280
it's still at a low
temperature by our standards,

00:05:58.280 --> 00:06:00.180
but it's a much higher temperature

00:06:00.180 --> 00:06:02.080
than the boiling point for Helium.

00:06:02.080 --> 00:06:07.080
It's at negative 185.8 degrees Celsius.

00:06:07.950 --> 00:06:11.030
So one way to think about
this, if you were at say,

00:06:11.030 --> 00:06:15.844
negative 270 degrees
Celsius, you would find

00:06:15.844 --> 00:06:19.230
a sample of Helium in a liquid state.

00:06:19.230 --> 00:06:21.030
But as you warm things up,

00:06:21.030 --> 00:06:26.030
as you get beyond negative
268.9 degrees Celsius,

00:06:26.170 --> 00:06:29.870
you're going to see that
those London dispersion forces

00:06:29.870 --> 00:06:32.450
that are keeping those
Helium atoms together,

00:06:32.450 --> 00:06:34.950
sliding past each other in a liquid state,

00:06:34.950 --> 00:06:38.756
they're going to be overcome by the energy

00:06:38.756 --> 00:06:40.670
due to the temperature.

00:06:40.670 --> 00:06:42.550
And so they're going to
be able to break free

00:06:42.550 --> 00:06:46.420
of each other and essentially
the Helium is going to boil.

00:06:46.420 --> 00:06:49.160
And you're going to enter
into a gaseous state,

00:06:49.160 --> 00:06:51.890
the state that most of us
are used to seeing Helium in.

00:06:51.890 --> 00:06:55.970
But that doesn't happen for
Argon until a good bit warmer,

00:06:55.970 --> 00:06:57.580
still cold by our standards,

00:06:57.580 --> 00:07:00.040
and that's because it takes more energy

00:07:00.040 --> 00:07:03.350
to overcome the London
dispersion forces of Argon

00:07:03.350 --> 00:07:08.350
because the Argon atoms
have larger electron clouds.

00:07:10.320 --> 00:07:13.750
So generally speaking,
the larger the molecule,

00:07:13.750 --> 00:07:15.570
because it has a larger electron cloud,

00:07:15.570 --> 00:07:17.260
it will have higher polarizability,

00:07:17.260 --> 00:07:19.190
and higher London dispersion forces.

00:07:19.190 --> 00:07:22.080
But also, the shape of
the molecule matters.

00:07:22.080 --> 00:07:24.750
The more that the molecules
can come in contact

00:07:24.750 --> 00:07:26.270
with each other, the more surface area

00:07:26.270 --> 00:07:27.820
they have exposed to each other,

00:07:27.820 --> 00:07:29.570
the more likely that they can induce

00:07:29.570 --> 00:07:30.960
these dipoles in each other.

00:07:30.960 --> 00:07:33.810
For example, butane can
come in two different forms.

00:07:33.810 --> 00:07:35.960
It can come in what's known as n-butane,

00:07:35.960 --> 00:07:37.323
which looks like this.

00:07:38.790 --> 00:07:40.940
So you have four Carbons
and ten Hydrogens.

00:07:43.002 --> 00:07:46.160
Two, three, four, five, six,

00:07:46.160 --> 00:07:50.830
seven, eight, nine, ten.

00:07:50.830 --> 00:07:53.750
This is known as n-butane.

00:07:53.750 --> 00:07:57.060
But another form of
butane known as iso-butane

00:07:57.060 --> 00:07:58.313
would look like this.

00:07:59.671 --> 00:08:01.340
Three Carbons in the main chain,

00:08:01.340 --> 00:08:03.740
then you have one Carbon
that breaks off of that

00:08:04.596 --> 00:08:08.923
middle Carbon and then
they all have four bonds.

00:08:08.923 --> 00:08:09.940
And the left over bonds, you could say,

00:08:09.940 --> 00:08:11.760
are with the Hydrogens.

00:08:11.760 --> 00:08:15.040
So it would look like this.

00:08:15.040 --> 00:08:18.721
This right over here is iso-butane.

00:08:18.721 --> 00:08:22.225
Now if you had a sample
of a bunch of n-butane,

00:08:22.225 --> 00:08:25.180
versus a sample of a bunch of iso-butane,

00:08:25.180 --> 00:08:26.670
which of these do you think will have

00:08:26.670 --> 00:08:28.780
a higher boiling point?

00:08:28.780 --> 00:08:30.680
Pause this video and think about that.

00:08:32.160 --> 00:08:35.320
Well if you have a bunch of
n-butanes next to each other,

00:08:35.320 --> 00:08:39.350
imagine another n-butane right over here.

00:08:39.350 --> 00:08:41.600
It's going to have more surface area

00:08:41.600 --> 00:08:45.970
to its neighboring butanes
because it is a long molecule

00:08:45.970 --> 00:08:50.320
It can expose that surface
area to its neighbors.

00:08:50.320 --> 00:08:52.480
While the iso-butane in some ways

00:08:52.480 --> 00:08:53.860
is a little bit more compact.

00:08:53.860 --> 00:08:55.050
It has lower surface area.

00:08:55.050 --> 00:08:56.920
It doesn't have these big long chains.

00:08:56.920 --> 00:08:59.800
And so because you have these longer

00:08:59.800 --> 00:09:01.911
n-butane molecules you're going to have

00:09:01.911 --> 00:09:05.040
higher London dispersion forces.

00:09:05.040 --> 00:09:08.190
They obviously have the same
number of atoms in them.

00:09:08.190 --> 00:09:10.130
They have the same number
of electrons in them.

00:09:10.130 --> 00:09:12.637
So they have similar
sized electron clouds.

00:09:12.637 --> 00:09:14.430
The have the same molar mass.

00:09:14.430 --> 00:09:17.040
But because of n-butane's elongated shape,

00:09:17.040 --> 00:09:18.680
they're able to get closer to each other

00:09:18.680 --> 00:09:21.080
and induce more of these dipoles.

00:09:21.080 --> 00:09:23.010
So just by looking at
the shape of n-butane

00:09:23.010 --> 00:09:25.050
versus iso-butane, you'd see higher

00:09:25.050 --> 00:09:27.410
London dispersion forces in n-butane,

00:09:27.410 --> 00:09:30.240
so its going to have a
higher boiling point.

00:09:30.240 --> 00:09:31.880
It's going to require more energy

00:09:31.880 --> 00:09:34.710
to overcome the London dispersion forces

00:09:34.710 --> 00:09:36.973
and get into a gaseous state.