Weight is how heavy an object is. One way to find the weight of an object is to multiply the mass of the object by the gravity. (The abbreviation for gravity, g, is the same as the abbreviation for gram. Be careful not to confuse these two uses.)


At sea level on Earth, gravity is 1, or 1 g.

The moon's gravity is of the gravity on Earth, or g.

When Apollo 15 was launched from Cape Kennedy, Florida, in July 1971, it carried the first Lunar Rover. This vehicle, which looked a lot like a dune buggy, weighed about 462 pounds on Earth. It weighed about 77 pounds when it landed on the moon.

Although weight is not the same as mass, people often use them to mean the same outside the field of science.

Did you know?

You would weigh slightly less at the top of Mount Everest than you would at sea level because the gravity at the summit is a little less than 1 g.

Related word weigh.

See also U.S. customary units, Metric system.