OK. Float a ball in a beaker of water in an elevator. The ball floats because the buoyant force of the water displaced by the ball is equal to the weight of the water.

Now, accelerate the elevator upward. What happens to the ball? Does it: Sink lower, rise higher, or stay the same?

Here’s my video with the answer:

Once the video is playing, you can click on it to get to the YouTube page with larger size and high definition versions.