Learn it
Matter is anything that has mass and takes up space (volume). Air, water, rock and you are all matter. Light, sound and heat are not matter; they are forms of energy.
Matter has properties we can observe or measure: color, hardness, mass, volume, density (mass ÷ volume), boiling and melting points, and whether it conducts electricity or dissolves in water.
Example: a block with a mass of 60 g and a volume of 20 cm³ has a density of 60 ÷ 20 = 3 g/cm³. Water’s density is about 1 g/cm³, so this block sinks.
🔎 Amazing facts
- Air has mass: a large room’s air can have a mass of more than 100 kg.
- Gold is so dense that a 1-liter carton full of it would have a mass of about 19 kg.
🧪 Try it: Measure density
- Find the mass of a small rock or toy on a kitchen scale (grams).
- Fill a measuring cup with water and note the level (mL).
- Drop the object in and note the new level; the difference is its volume (1 mL = 1 cm³).
- Calculate density = mass ÷ volume. Predict: sink or float?
Think about it: Does cutting the object in half change its density?