Difference Between Mass and Weight: Common Mistakes Explained with Interactive Animation

❌ Common Mistakes: Confusing Mass & Weight

What is Mass?

• Mass is the amount of matter in an object.
• It is measured in kilograms (kg) or grams (g).
• Mass does not change no matter where the object is in the universe.
• Example: A rock with a mass of 1kg has that same mass on Earth, the Moon, or Mars.

What is Weight?

• Weight is the force with which gravity pulls on an object.
• It is measured in newtons (N).
• Weight = Mass × Gravity (W = m × g)
• Weight changes if you go to a place with different gravity.
• Example: The same 1kg rock weighs less on the Moon than on Earth.

Compare Mass & Weight

	Mass	Weight
What is it?	Amount of matter	Force of gravity on object
Unit	kg or g	newton (N)
Changes with location?	No	Yes
Measured by	Balance scale	Spring scale

Example: 1kg Mass on Different Planets

• On Earth: Weight = 1kg × 9.8 m/s² = 9.8N
• On Moon: Weight = 1kg × 1.6 m/s² = 1.6N
• On Mars: Weight = 1kg × 3.7 m/s² = 3.7N

Common Mistake

• Many people say "weight" when they mean "mass", or think they are the same thing.
• Remember: Mass never changes, but weight depends on gravity!

Quick Tip

Scales at the grocery store measure mass, not weight! Even though they may be marked in "kg", they are designed for Earth's gravity.

Common Mistake: Confusing Mass & Weight

1kg

?

On Earth, a 1kg mass weighs 9.8N. Mass stays the same, but weight changes with gravity!