Video Tutorial: airlift
Full instructions are below, but you can also check out Krissy, CME’s Director of Education and Outreach, with her son Aiden in their kitchen showing us this experiment!
Let’s learn about compressed air!
When you blow air into a bag, the air is pushed together, or “compressed.” The compressed air pushes on the bag which makes the bag push on the book, lifting it up. So the bag filled with compressed air can support the weight of the book. The tires on your bike work in the same way. They are filled with compressed air and can support your weight. When the air leaks out of bike tires, they can no longer support your weight. That is why it’s hard to ride your bike when the tires are flat.
1. Place a heavy book on top of the plastic bag. Let about two inches of the bag stick out from under the book.
2. Poke a hole in the bag with the pencil.
3. Stick the straw in the hole. Use tape to seal the hole around the straw so no air can escape.
4. Blow into the straw. Hold your tongue over the straw to keep air from leaking out when you take a breath.
What happens? Can you lift the book off the table?
If you have other materials at home, you might try again and see what happens:
What happens if you use a balloon or garbage bag instead of a plastic bag? What happens if you use more than one bag? Can you lift a large object, like a table? Choose one thing to change (that’s the variable), and predict what you think will happen.
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