Video: Watch this demo
Description: As a pale of water is spun in a circle, the water does not fall out. This is because the string provides a centripetal force, while the inertia of the pale of water (Newton’s first law) causes an apparent “centrifugal force”, which keeps the water in the pale.
Note: If you go too slow, the water will fall out.
Equipment:
- Metal pale with rope tied to the handle
- Water
Setup Procedure:
- Check to make sure strings are securely attached.
- Can fill the pale ahead of time, or leave for professor to fill in class. Ask what is preferred.
Demonstration Procedure:
- Carefully start swinging the water-filled pale.
- Get it going as fast as possible, as soon as possible.
- When stopping, try to stop gradually so as to avoid spilling water all over the floor. You have to use some physics intuition to get the hang of this!