Year 8 · Science · KS3 · free one-page sheet

Separating mixtures

Made by TheLearnDen editorial team · Checked by TheLearnDen editorial team, against the KS3 science programme of study, Chemistry: pure and impure substances (DfE, 2013) (source) · Last updated 23 August 2026

A free one-page printable on separating mixtures for Year 8 (KS3) science: filtration, evaporation, distillation and chromatography in one table, a worked example, the "filter the salt out" mistake, and three recall questions. It belongs to our Year 8 Science page on this topic, where every linked resource has been checked.

The Separating mixtures one-page sheet. The full text is written out below the image.

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The sheet, written out

Key idea

A mixture can be separated by finding a property that is different for the things in it: whether a solid is dissolved, how easily a liquid evaporates, or how the parts of a dye behave on paper. Match the difference to the method.

Pick the method from the difference

Filtration

uses particle size

insoluble solid from a liquid
sand from water

Evaporation

the water evaporates from the surface, even below its boiling point

dissolved solid from a solution
salt from salty water

Distillation

the water boils off, is cooled and collected

the liquid from a solution
pure water from salty water

Chromatography

some dyes dissolve more readily, others are held more strongly by the paper

dyes mixed in a liquid
the colours in a felt-tip ink

Worked example

You have a beaker of muddy salt water. Describe how to get clean dry salt from it.

First filter it. The mud is an insoluble solid, so it stays in the filter paper; the salt is dissolved, so it passes through with the water.

Then gently warm the salt solution so some of the water evaporates and the solution becomes concentrated. Leave it to cool: salt crystals form. Filter them off and leave them to dry.

The common mistake

"Filter the salt water to get the salt out."

Filtration only catches solids that are not dissolved. Dissolved salt particles are far smaller than the holes in the filter paper, so the salt goes straight through with the water. To separate a dissolved solid you need evaporation, or distillation if you want the liquid instead.

Test yourself

Which method separates sand from water?
You want to keep the water from salty water, not the salt. Which method?
Why do the dyes in an ink travel different distances up the paper?

Answers (printed upside down on the sheet): 1. Filtration. 2. Distillation. 3. Some dissolve more readily in the solvent and some are held more strongly by the paper, so they can separate.

Next topic

Mixtures, including dissolving

Questions parents ask

What are the four ways of separating mixtures at KS3?

Filtration (an insoluble solid from a liquid), evaporation (a dissolved solid from a solution), distillation (the liquid from a solution) and chromatography (dyes mixed in a liquid). Each uses a difference: whether something is dissolved, how easily a liquid evaporates, or how the dyes dissolve and how strongly the paper holds them.

Why can't you filter salt out of salt water?

Dissolved salt particles are far smaller than the holes in filter paper, so they pass straight through. Evaporation leaves the salt behind; distillation collects the water.

When is this taught?

Simple techniques for separating mixtures, filtration, evaporation, distillation and chromatography, are in the Key Stage 3 science programme of study in England, usually taught in Year 7 or 8.

Is the sheet free?

Yes. One A4 page, PDF or PNG, no sign-up. Print at 100% (actual size).