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Gravity is the force by which a planet or other body draws objects toward its center. The force of gravity keeps all of the planets in orbit around the sun.

This website provides good information and examples of gravity, mass and weight.

The weight of an object is defined as the force of gravity on the object and may be calculated as the mass times the acceleration of gravity, w = mg. Since the weight is a force, its SI unit is the newton.

Weight is just another word for the force of gravity. Weight is a force that acts at all times on all objects near Earth.

We use the word mass to talk about how much matter there is in something. (Matter is anything you can touch physically.)

Mass is a measurement of how much matter is in an object. Mass is a combination of the total number of atoms, the density of the atoms, and the type of atoms in an object.