Mixtures and separating them

Ages 9 to 12 Read alone or together · about 30 minutes

Read together

A mixture holds two or more substances that are not chemically joined. You can often separate them.

Sieves, filters and evaporation each separate in a different way.

Do it

1. Mix sand, salt and small pebbles in a bowl.
2. Use a sieve for the pebbles. Add water and stir to dissolve the salt.
3. Pour through a coffee filter to catch the sand. Leave the salty water in a dish in the sun to evaporate.
4. Describe each step and what was left behind.

Talk about it

• Which method separated the pebbles?
• What was left after evaporation?

For the grown-up

Physical separation (sieving, filtering, evaporating) works because the parts keep their own properties. Do not taste the mixture. Supervise water and keep salt from eyes.

Mark as done

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Where this comes from

• NGSS Lead States, Next Generation Science Standards: For States, By States (National Academies Press, 2013), performance expectation 5-PS1-4 (chemical and physical changes, mixtures)
• American Chemical Society, educational pages on mixtures and separation techniques

Written with AI assistance and checked against the sources listed. Please read it before sharing it with a child.