Today at the Fort, we’re blowing bubbles!
This is an official summer fun alert!
If you’ve had a chance to blow bubbles at
school, or in your backyard, then you know
that it can be really fun to make them — and
pop them!
And they’re also a pretty cool way to learn
some science!
First, let’s practice blowing bubbles!
To blow bubbles, you need two things: bubble
liquid, which is mostly made of soap and water,
and the stick you blow the bubbles out of,
which is called a wand.
I’ll dip my wand into the bubble liquid
and blow—but not too hard!
If I blow too hard, then I’ll blow the liquid
right out of the wand.
But if I gently blow a steady stream of air
through the bubble liquid …
and I get a bunch of bubbles!
Bubbles are really just a thin layer of soap
and water around a pocket of air.
If we could cut a bubble in half and look
at it really closely, we would see that the
bubble is actually made up of layers.
There’s a layer of water between two layers
of soap.
It looks kind of like a sandwich!
The soap layers are like the bread of a sandwich,
and the water is like the sandwich filling.
The layers of the bubble surround the air
inside the bubble, and keep it inside.
Water without soap doesn’t make bubbles
very well, because water likes to stick together.
Water’s made up of lots of little tiny pieces,
or particles, so small that you can’t even
see them.
But they’re there!
These particles are attracted to each other,
meaning that they’re pulled toward each
other like magnets.
So they stick together!
For example, check out this insect!
It can walk on the top of this pond because
the particles that make up the water in the
pond are all attracted to each other.
They stick together so much that the insect
can walk on the water without falling in!
The little particles in water are pulled together
so strongly that they can’t spread out into
a thin bubble with air inside.
The water in the bubble would just pull back
together into a droplet!
But when you add soap, it helps the water
spread out without being pulled back together,
by making that soap-and-water sandwich.
And you get bubbles!
There’s something else that’s special
about bubbles.
Bubbles can be lots of different sizes, from
super tiny to gigantic.
But have you noticed that they’re all the
same shape?
[Squeaks squeaks]
That’s right — they’re round!
Just like the wand we used to blow the bubbles.
What would happen if we used a wand that has
different shape?
Like this one!
[Squeaks squeaks]
Right, Squeaks!
[can change triangle to square or rectangle
or whatever shape it actually is]
This wand is shaped like a triangle.
So, what do you think will happen when I blow
bubbles out of this triangular wand?
[Squeaks thinks they’ll be triangular]
You think they’ll be shaped like a diamond?
OK, let’s try it and see what happens.
When I dip the wand into the bubble liquid
and blow … the bubbles are still round!
Even though the wand I blew the bubbles out
of /wasn’t/ round.
It’s round because of that water layer,
the filling of the bubble sandwich.
Even though the soap helps the water spread
out into a bubble by making the particles
in the water less attracted to each other,
they’re still a little bit attracted to
each other.
And when the water particles pull on each
other around the air inside, they give the
bubble its round shape.
Even if our wand has corners, the attraction
in the particles that make up water pull those
corners out, and give us a nice round bubble
every time.
[Jessi blows some bubbles to demonstrate.
Squeaks pops them.]
I guess you like popping bubbles, Squeaks!
[Squeaks agrees]
I do too!
It’s really fun.
But do you know /why/ they pop?
If something manages to break the attraction
between the water particles that make up the
bubble’s water layer, like Squeaks’ nose
or my finger, the air is able to get out,
and the bubble pops!
It’s a lot like popping a balloon with something
sharp.
When you poke a hole in a balloon, the air
gets out and the balloon pops.
When you touch a bubble with your finger,
you’re basically poking a hole in the bubble.
Want to pop some more bubbles, Squeaks?
[Squeaks nods and squeaks]
OK, let’s head outside and make some bubbles!
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See you next time!
