Worksheets and lesson ideas to challenge students aged 11 to 16 to think hard about chromatography (GCSE and Key Stage 3)
Chromatography is a really useful tool to separate out a mixture containing many dissolved solids (solutes). To really understand chromatography students must understand the concepts of solute, solvent, solution and solubility. The reason substances move different distances along the chromatography paper is all about their solubility in the solvent. The more soluble the particles are in the solvent, the further they travel up the paper. This video below demonstrates an easy method to extract chlorophyll from leaves. The extracted pigments can then be separated using chromatography.
Chromatography of ink
KS3 practical on the chromatography of ink. Students carry out a simple practical to separate the ink from different felt tip pens. This method can be modified to extract chlorophyll from leaves (see above). (PDF)
KS3 activity to interpret chromatograms. Students apply their knowledge of chromatography to a new context involving food colours and hyperactivity. They use evidence from a chromatogram to determine whether two drinks are safe for a child. This resource was contributed by Jill White. It is an excellent way of helping students use evidence to support a claim. (PDF)