Mass vs. Weight
The difference between who you are (matter) and where you are (gravity).
The Fundamental Distinction
While often used interchangeably in daily conversation, science draws a hard line between these two concepts.
Mass (m)
📦- ➤ Definition: The amount of matter in an object.
- ➤ Unit: Kilogram (kg).
- ➤ Property: Constant. It does not change regardless of location.
- ➤ Type: Scalar (Magnitude only).
Weight (W)
⚓- ➤ Definition: The force of gravity acting on an object.
- ➤ Unit: Newton (N).
- ➤ Property: Variable. Changes based on gravitational pull.
- ➤ Type: Vector (Magnitude + Direction).
The Mathematical Link
Mass and Weight are connected by gravity. The formula is simple but powerful:
*On Earth, gravity (g) is approximately 9.8 m/s². A 10kg object weighs 98 Newtons here.
How do we measure them?
Beam Balance (Mass)
Compares unknown mass to known mass. Works the same on the Moon because gravity cancels out on both sides.
Spring Scale (Weight)
Measures the pull force. On the Moon, the spring stretches less because the pull is weaker.
Cosmic Weight Simulator
Use the slider to change the Mass. Notice how the Mass stays constant (you are still you), but your Weight fluctuates wildly depending on the planet's gravity.
Your Mass Everywhere
70 kg
Gravity on Earth
9.8 m/s²
Gravity on Jupiter
24.79 m/s²
Calculated Weight (Newtons) Across The Solar System
Calculated using W = m × g for each celestial body.
Quick Reference: Mass vs. Weight
| Feature | Mass | Weight |
|---|---|---|
| What is it? | Amount of matter | Force of gravity |
| Change with Location? | NO (Constant) | YES (Variable) |
| Can be zero? | No (implies non-existence) | Yes (in deep space) |
| Quantity Type | Scalar (No direction) | Vector (Downwards) |