Lesson 4: What is Mass?

What is Mass?

Definition: Mass is the amount of matter (or stuff) an object has.

Unit of Mass

• The SI unit for Mass is kilogram
• Abbreviated kg
• 1 kg = 1,000 grams
• 1 kg is about the mass of 1 textbook
• 1 g is about the mass of 1 paper clip

Mass is NOT...

• Volume
• How much space an object takes up
• Energy
• Heat
• Light

Mass is NOT Weight!

• Weight has to do with gravity
• Gravity is the force (push or pull), attracting an object towards another object, often the center of Earth

For example: If a ball’s mass is 100kg, it weighs about 220 lbs on Earth. The same ball will weigh about 37 lbs on the Moon. Because the moon’s gravity is ⅙ of Earth’s gravity. The ball’s mass stays the SAME on Earth and the moon, but it’s weight CHANGES.

What is Mass used for?

• Density
• Density= Mass / Volume
• Force
• Force = Mass x Acceleration

• Weight ha