If you pick up a brick in one hand and a pencil in the other, you immediately notice how the brick is much heavier than the pencil. The brick is bigger so it makes sense that it’s heavier, right? It isn’t always that simple! Pick up an empty plastic lunchbox that’s bigger than the brick and you’ll find that the brick is still heavier, the reason for this is due to the mass of the brick being greater than the mass of the lunchbox!
Mass measures how much matter is in an object, combining the total number of atoms (tiny particles that make up everything in the universe) and the density of these atoms in an object affects how much mass is in the object. The more mass in an object, the heavier it will appear to be. Mass is measured in kilograms or pounds and comes in different types, two of the most common are:
- Inertial Mass – This measures how much an object resists acceleration. So if you try to push two things, the one with the least amount of mass will move faster. Think of how much easier it would be to push a bicycle than to push a car, the bicycle would move much faster than the car when using the same amount of force!
- Gravitational Mass – This measures how much gravity an object exerts on other objects. So if you put one object on top of another, the object on top will exert force onto the object underneath it. For example, if you somehow placed a car on a frail wooden table, the car would have enough gravitational mass to force the table down and break it!
Just remember that mass is not to be confused with weight. While they are related, they are not the same thing!
The video above helps explain mass in a fun way!
Inquiry – Digging Deeper
Check out the video below which shows how you can figure out the mass of an object using a simple balance measure. This is something you can even try in class and have fun with objects of different sizes!