Metric System:
Mass and Weight

Mass

• Mass is the amount of matter in an object.

• Matter is anything that takes up space.

• Mass is measured with a triple-beam balance.

Units for Mass

• The metric unit for mass is the gram

• 1000 grams (g) = 1 kilogram (kg)

• It takes 454 grams to make 1 pound and 2.2 pounds to make 1 kilogram

Weight

• Weight is the amount of gravity’s pull on an object.

• Weight is measured with a spring scale.

Mass vs Weight

• The amount of mass an object has does not change with location or altitude, while its weight does.

• Mass stays the same, weight changes with gravity

Example 1

• If a bowling ball has a mass of 6 kilograms here on Earth, it would also have a mass of 6 kilograms on the Moon. Its weight would be 6 kilograms on Earth, but only 1 kilogram on the Moon.

• Why?

• The gravity on the Moon is 1/6th that of the Earth.

Example 2

• This also means that objects weigh different amounts at different places on the Earth. You weigh more in Santa Maria than in Denver.

• Why?

• Santa Maria is closer to the center of the Earth than Denver.