Skill: Measure and compare mass

Mass tells how much matter is in an object. We measure mass with a scale, usually in grams (g) or kilograms (kg). A bigger-looking object is not always heavier.

Remember:

$$1\text{ kilogram}=1{,}000\text{ grams}$$

Example: A box has a mass of $(1\text{ kg }200\text{ g})$. A bag has a mass of $(850\text{ g})$. Which object is heavier, and by how much?

Step 1: Use the same unit.
Change the box’s mass to grams:

$$1\text{ kg}=1{,}000\text{ g}$$ $$1\text{ kg }200\text{ g}=1{,}000\text{ g}+200\text{ g}=1{,}200\text{ g}$$

Step 2: Compare the masses.

$$1{,}200\text{ g}>850\text{ g}$$

So, the box is heavier.

Step 3: Find how much heavier.

$$1{,}200\text{ g}-850\text{ g}=350\text{ g}$$

The box is $(350\text{ g})$ heavier than the bag.