Hold the potato in your non-dominant hand (the hand you don’t write with) and try to stick a straw through it. What happens? The straw bends and crumples!
Now, cover the top of the straw with your thumb. Hold the potato on one end and try sticking the straw through the other end.
We cut the bent part of the straw off after step 2!
If you can stick a straw through a potato, you can probably stick a straw into your fingers too! Make sure to hold the potato on the opposite side of where you’ll be sticking the straw.
How can you turn a flimsy straw into something sturdy enough to stick through a potato? The same way that you turn bouncy rubber into a rugged car tire, or a bulky jackhammer into a concrete-breaking machine: with air pressure!
When you cap your thumb over the end of the straw, you capture the air inside the straw too. We don’t normally think about the air in a straw (or the air all around us), but the air is there, taking up space and bouncing off the sides of the straw.
A neat thing about gases (like air) is that when they get squished, they transfer that squishing pressure to their containers. A squished gas has less space to move in, so the gas bounces around its container faster and harder. If you’ve ever squeezed a balloon and seen it bulge out, you’ve seen air pressure at work. In this experiment, the air inside the straw gets squished (and pressurized) when you jam the straw into the potato. The squished air pushes out on the sides of the straw and keeps the straw from bending — that’s the power of air pressure!
Experiment with air pressure and poke some holes in one of our favorite vegetables!
It’s kind of strange to think about the invisible air that’s all around you. But it’s very important that it’s there, and for more than just breathing! Check out some other awesome things that air pressure can do with a leaky water bottle.
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