Skill: Order objects by mass

Mass tells how heavy or light something is. An object can be big but light, or small but heavy, so look at how heavy it feels—not its size.

To order objects:

1. Compare two objects at a time.
2. Decide which is lighter or heavier.
3. Start with the lightest object and move toward the heaviest.
4. If two objects feel the same, they are equal in mass.

Example: Put a pencil, an apple, and a book in order from lightest to heaviest.

• The pencil is lighter than the apple.
• The apple is lighter than the book.

So, the pencil is also lighter than the book.

The order is:

$$\text{pencil} \; \rightarrow \; \text{apple} \; \rightarrow \; \text{book}$$

Therefore, the order from lightest to heaviest is pencil, apple, book.