What Is a Mixture?
≈ 18 minA mixture is two or more materials put together in the same place, where each material keeps its own properties.
That second half of the definition is the important part. When you stir sand into iron filings, the sand stays gritty and pale, and the iron stays grey and magnetic. Nothing new was made — the two materials are simply sharing a container. Because each material is still itself, a mixture can usually be separated again.
Some everyday mixtures:
| Mixture | What is in it |
|---|---|
| Sea water | water + dissolved salts |
| Air | nitrogen + oxygen + other gases |
| Soil | sand, clay, small stones, rotted plant material, water, air |
| Mielie meal with sugar stirred in | mielie meal + sugar |
| Muddy river water | water + suspended soil particles |
Worked example — testing whether something is a mixture.
A learner is given a grey powder. She checks it with two tests:
- She holds a magnet near it: some of the powder jumps to the magnet, the rest does not.
- She looks at the leftover powder with a hand lens: it is pale and gritty.
Since part of the sample behaves like iron and part behaves like sand, both materials have kept their own properties. It is a mixture of iron filings and sand — and the magnet has already started separating it.
Which of these is a mixture?
In a mixture, each material keeps its own ______, which is why the mixture can be separated again.
Thandi stirs sugar into her tea and says, "The sugar has disappeared — it is gone." What is the best scientific reply?
A learner mixes g of sand with g of salt. What is the total mass of the mixture, in grams?