A bucket of water is swung in a vertical circle without the water spilling out. This demonstrates inertia and the role of centripetal force in circular motion.

1. Fill a sturdy bucket about halfway with water.
2. Hold the bucket securely by its handle.
3. Begin swinging the bucket back and forth in an arc to build up momentum.
4. Gradually extend the swing into a full vertical circle, keeping the speed fast enough so the water remains inside.
5. Continue for several rotations, then slow down and stop carefully.

Why does the Water stay in this Bucket?! - The Science Asylum:

Centripetal Force on a Swinging Bucket | Newtons Laws | Physics Explained - INTEGRAL PHYSICS:

📄 What keeps the water in the pail? - University of Wisconsin-Madison: https://wonders.physics.wisc.edu/water-pail/

• Try using different amounts of water to see how mass affects the motion.
• Use a transparent container (plastic jug with lid and holes) to let students see the water pressing against the sides during motion.
• Swing the bucket in a horizontal circle to compare forces with the vertical case.

• Ensure the swinging area is clear of people and objects.
• Use a strong bucket with a secure handle to prevent accidents.
• Do not overfill the bucket.
• Perform the demonstration outdoors or in a space where spilled water is not a problem.

• Why doesn’t the water fall out when the bucket is upside down? (Because the centripetal force is greater than gravity when the bucket is moving fast enough.)
• What happens if you swing the bucket too slowly? (The water will spill out because gravity becomes stronger than the centripetal force.)
• How is this similar to the feeling of being pushed against the door when a car takes a sharp turn? (Both involve inertia resisting a change in straight-line motion.)