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!