Separate three inks in a KS3 paper chromatography virtual lab, then practise reading chromatograms with a printable worksheet and answer sheet.

Can a single ink spot hide several dyes? Pupils predict which of three water-soluble inks will produce the most spots, then test their prediction. As water rises up the paper, they watch the dyes travel different distances. The finished pattern gives them evidence they can use to explain which inks contain more than one dye.

What pupils do in the virtual lab

• Prepare the paper, draw a pencil baseline and place three small ink spots along it.
• Lower the bottom of the paper into water, keeping the ink spots above the water level.
• Watch the dyes separate. Remove the paper before the water reaches the top and mark the solvent front in pencil.
• Draw the chromatogram, label the start line and solvent front, and count the spots in each sample lane.
• Use their observations to identify the stationary phase (paper) and mobile phase (water), and explain why the baseline is drawn in pencil.

Printable worksheet and answers

The worksheet gives pupils a second chromatogram to interpret. They check the starting setup, put the method in order and compare a mixture with three reference samples. To identify a possible match, they look for spots that travelled the same distance from the start line. A completed answer sheet supports marking or pupil self-assessment.

Where it fits in your scheme of work

Use this resource alongside the White Rose Science Year 7 Chromatography lesson in the separation techniques unit. It also supports Exploring Science, including Exploring Science International, and AQA Activate lessons on separating mixtures and interpreting chromatograms.

For a whole-class lesson, project the lab and pause just before the paper enters the water. Ask pupils to mark the water level on their own diagram and explain what would happen if the ink spots were submerged.