Place a small rubber ball on top of a basketball or soccer

ball and then drop them together. If vertical alignment nicely
remains as they fall to the floor, you’ll see that the small ball
bounces unusually high. Can you reconcile this with energy
conservation?

yes, of course. The basket ball loses KE...

This is a neat math problem, momentum is conserved.

The phenomenon you described, where a small rubber ball bounces unusually high when dropped on top of a basketball or soccer ball, may seem contradictory to the principle of energy conservation. However, understanding the concept of energy transfer during the collision can help reconcile this apparent discrepancy.

When the two balls are dropped together, the potential energy of the system is initially stored as gravitational potential energy. As they fall, this potential energy is converted to kinetic energy, causing both balls to gain velocity. Eventually, they collide with the floor, and the kinetic energy is transferred to the ground and dissipated as sound and heat. At this point, the energy conservation principle holds true.

Now, let's focus on what happens when the small rubber ball collides with the larger ball. During the collision, the small ball compresses and deforms due to the impact. This compression stores potential energy in the form of elastic potential energy. As the small ball deforms, the potential energy within it increases.

When the small ball reaches its maximum compression and starts to rebound, this potential energy is converted into kinetic energy. Since the small ball is relatively lighter compared to the larger ball, it gains more kinetic energy during the rebound. Consequently, it bounces back with a higher velocity, resulting in a higher bounce height.

Although the small ball's bounce seems to contradict energy conservation, it actually follows the principle. The extra energy observed comes from the potential energy stored in the small ball during compression. When it rebounds, this potential energy is converted back into kinetic energy.

It's important to note that this phenomenon is possible due to the elastic properties of the small rubber ball and its ability to store and release potential energy through deformation. In other scenarios where the balls are not as deformable or have different materials, the result might be different.