Look carefully at the pictures below. Can you figure out which plastic water bottle will hit the floor first?
There are three choices: one is filled with water, one is filled with dice, one is empty.

If you are an EVG sixth grader, you know that MOMENTUM = MASS X VELOCITY.
And therefore you figured out the answer--the bottle with the greater mass would hit first.
(Ask a student in Mrs. Castaldo's class for the details.)