Mass is how we measure the amount of matter in some-thing. The more massive is, the more of a gravitational

pull it exerts and as we walk on the surface of the earth, it pulls on us, and we pull back.

Sine the earth is so much more massive then us , the pull from us is not strong enough to move the earth, while the

pull from the earth can make us fall flat on our faces.

We need gravity to keep us on earth!

EARTH

This is the heavy mass, pulls in everything around it.

Balls falling into the middle because it’sbeen pull by the heavy mass in the middle

Experiment By Galileo‘‘ON THE MOON’’

Galileo performed an experiment from the top of the leaning tower of Pisa. He dropped two spheres of different weight and observed that both hit the ground

at the same time.