Tissue Paper Lift
Question: What happens if you cut a strip of tissue paper or other thin paper, hold it just below your lips, and blow?
Answer: The paper lifts up and flaps in the breeze, like this:
Before (left) and during (right) blowing over the tissue paper.
But why? It seems like the wind from your breath should push down the paper. Instead, it lifts up the paper. If you looked at Ceiling Fan and Balloon Science a couple weeks ago, you might already know what’s going on here. The faster-moving air from you blowing is at a lower pressure than non-moving air. So when you blow over the strip of paper, the higher-pressure air below pushes up the paper.
This is also a great example for some experimenting. Here are some questions that kids could test:
- Does the strength of the blowing play any part?
- Does the length of tha piece of paper have any impact?
Maybe your kids can find even more questions to test. Have fun!