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Mixing

Radiation and the atom · level 1, lesson 2 of 6

A question to start

Stir some raisins into a bowl of cereal. Is it a new kind of food, or still cereal and raisins?

The idea

When you stir different things together, you make a mixture. The things in a mixture are still there, each one still itself. They are just jumbled up.

  • Cereal and raisins: you can still see and pick out both.
  • Sand and pebbles: still sand, still pebbles.
  • Air: a mixture of gases you cannot see, mostly nitrogen and oxygen.

Some mixtures are easy to see, like a fruit salad. Others look like one thing, like air or tap water, but are mixtures too.

cereal and raisins: a mixture

Worked examples

1. A fruit salad. Apple, banana and grapes, all mixed. Each piece is still apple, banana or grape.

2. Sand and salt. Stir them together. It looks like one powder, but it is still sand and salt.

3. Air. You breathe a mixture every moment. Most of it is nitrogen, and about a fifth is oxygen.

Try it

  1. What is a mixture?
  2. In a bowl of cereal and raisins, are the raisins still raisins?
  3. Name a mixture you can see the parts of.
  4. Name a mixture you cannot see the parts of.
Answers
  1. Different things stirred together, each still itself.
  2. Yes.
  3. Any one: a fruit salad, cereal and raisins, sand and pebbles.
  4. Any one: air, tap water, sea water.

Common mistake

"Mixing makes a new thing." In a mixture, nothing new is made. Everything that went in is still there, and it can be sorted out again.

Where it leads