Huff N’ Puff
What we learn about- Matter, air, pressure.
What we need: Bottle, thermocol balls/ paper balls
1) Put the thermocol ball or Paper ball loosely into the neck of the bottle. Make sure the ball is close to the mouth of the bottle.
2) Using the air from your mouth, attempt to blow a thermocol ball or Paper ball into the bottle.
How does it work?
- Huff and Puff Challenge has a lot to do with air pressure and air movement.
With an item like the paper ball resting at the mouth of the bottle, it would make sense that the air from the straw would blow it into the bottle, but the exact opposite happens.
- The secret is inside the bottle. Although we refer to the bottle as being “empty,” it’s actually full to the brim.
- The bottle is filled with air! Trying to blow more air into the bottle is impossible, just like if you were to put your lips directly on the mouth of the bottle and blow.
- It doesn’t work! While you can’t blow air into the bottle, you are moving quite a bit of air along the sides of the bottle.
- When the air blows past the mouth of the bottle, it creates an area of low pressure behind it. The air pressure inside the bottle is higher than near the mouth. The air inside the bottle pushes the ball out and does not allow it to go inside the bottle.
- This phenomenon is explained by Bernoulli’s Principle. It states that an increase in the speed of a fluid ( here air) occurs simultaneously with a decrease in pressure.