Because heat makes plastic expand in hot water.
about 144 ping pong balls are in a gross.
about 10cm2
The gas in the ping pong ball will expand, pushing the dent out.
10 ping pong balls
The heat from the boiling water warms up the air inside the ping pong causing the air to expand and push the dent of the ping pong back out.
If they float in water, then it is because the density of a ping pong ball is lighter than the density of water. The density of water is just below 1, and the density of a ping pong ball is much less than 1.
I have ping pong balls in my tank for my guys to play with.
No they do not.
Sure it can. But you'll need a lot a lot of ping pong balls- I believe the ratio is about 1 pound per 15 ping pong balls... then you can lift just about anything.
Slice one ping pong ball in half. Fill up the half of the ping pong ball with water. Empty the water from the ping pong ball into a measuring cup. Measure the amount of water in mL and multiply it by 2, ( there are two halves ).
There is insufficient information in the question to answer it. How are the ping-pong balls hanging? By what? Are they touching? What is the orientation of the straw with respect to the ping-pong balls? Please restate the question.
It the heat from the boiling water will expand the air inside the ball pushing the dent out. The same can be done with ping pong balls and a lighter.