Hi everybody and welcome to Cell-fie science.
I'm Jen a PhD student studying plant biology
and I want to bring you a quick does of science
from my cell phone.
Today I want to talk to you about the scientific
method.
So this a process that scientists use to make
observations and conclusions about the natural
world all around us.
It's often presented as a step-by-step process
but really you can jump in and out of the
scientific method at any point.
So traditionally it's presented as observe,
question, hypothesize, test, and report.
Reporting is very critical.
You need to tell everybody what the results
of your science was.
So when you're walking around you might make
the observation that tress are green in the
spring and then their leaves turn different
colors in the fall.
So you might question why?
Why does this happen?
You could hypothesize that the difference
between spring and fall is that it is cold
outside.
So perhaps you take some leaves and put them
in the cold and you wait and see if they turn
red or orange.
That would be a hypothesis, the leaves turn
orange because it is cold and then you designed
an experiment, I will put leaves in the cold
to test it.
And then you observed those leaves, did they
turn orange, yes, no?
No, they did not turn orange.
It's not the cold.
Or at least it's not just the cold.
Another really fun way to do this is with
plants, which is why I'm talking about it.
So you can take some plants and germinate
them so that they become nice and little.
Like these soybean which I have right here.
This is my study species so I'll be talking
about soybean a lot.
And you can make the observation that some
of them are big and some of them are little
and I want to get them to get bigger.
So my question would be, how do I make them
grow larger?
Well you could test different types of food.
So you could give them different types of
liquid that they could absorb through their
roots and see what happens.
Whenever you do science you need to have a
control.
So in this case your control would be water.
There is nothing in this water, it is just
water.
The plants aren't getting anything extra that
should be aiding their growth and you can
use the water treated plants to know how a
normal plant would grow.
You could also give them extra food, Miracle-Gro,
this is fertilizer it has extra nitrogen and
phosphorous that the plants need to grow and
you would assume they would grow larger and
faster than your water treated plants.
You could also ask other questions like how
does caffeine affect the growth of plants?
So this is just some coffee, right, caffeine
is in coffee.
How does it affect the plants as compared
to the ones you treated with water.
Or potentially even Gatorade, so this is just
some lemon lime Gatorade.
It's got water electrolytes and other stuff
in it so maybe you could use that.
You could also get creative and do Pepsi which
has a lot of sugar in it.
Or even just add sugar to your sugar water...
to make sugar water, add sugar to your water
to make sugar water to see how that impacts
the growth of your plant.
But what is impacting the growth even mean?
You have to have something you can measure.
Something you can take every single day.
And a good thing with plants is growth.
You just take yourself a ruler and you measure
how tall are my plants?
Every day you write down how many centimeters
tall it is, maybe over a week, then you can
see which plant grew the best under which
thing.
That would be your testing step.
Then you could bring maybe a poster or a picture
of your results to a science fair.
That's a report, you just told everybody in
your school or class about it.
One thing that a lot of people forget is replication.
Now in biology replication is incredibly important
because each one of these soybeans is a little
bit different.
I'll bring them in here so you can see.
See this guy right here, he is so much shorter
than these other guys.
They were all planted at the same time, same
pot, same light, same water, all of that,
but he's a little shorter.
And then maybe even look at these guys up
here, see these guys leaves are still a little
bent, these guys are flat.
They are all slightly different.
That's known as biological variation.
Our genes are different.
Soybean same thing.
Look around at people, we all look slightly
different.
Soybean have slightly different genetics.
So to account for that you need to have replicates,
lots of different individuals.
I'm getting ready for an experiment where
I'm actually going to use 9 individuals in
a single replicate and do 3 replicates, so
my whole experiment will be representative
of 3 times 9, 27 plants.
That's a lot of replication, hopefully it
will minimize the differences based on genetics
and maximize the differences based on treatment.
I hope you enjoy this little speech on the
scientific method and make sure when you're
getting ready for your science fairs that
you have a control, a clear way to measure,
and a lot of replication.
Have a good day everybody.
