Autumn Leaves

Now that the summer holidays are almost over, why not use the changing seasons & falling leaves to your advantage to inspire students using the outdoors before the winter weather sets in? You could take students on a woodland nature walk to collect various differently shaped & coloured leaves & use our A3 Trees & Shrubs Laminated Gatekeeper ID Guides to identify your findings.

Or how about combining the changing seasons outdoors with their chemistry lesson & ask students to carry out Thin Layer Chromatography on the different colours of leaves they can find? Thin Layer Chromatography is the separation of a mixture of substances using a stationary phase (silica on the TLC Plate) & a mobile phase (usually a liquid solvent).

The colouring from the leaves is extracted using chemicals, then is applied to a pencil line near the bottom of the TLC Plate using a fine paintbrush. The mobile phase moves through the stationary phase separating the components. Rf values can then be calculated to identify the components by measuring the distance each coloured spot travels up the TLC Plate.

CLEAPSS have a simple procedure for completing this experiment, which can be found on their website & accompanying YouTube Channel. Please check the procedure & hazards before completing this practical with your students. Students can try repeating the procedure, using different colours of leaves, and compare their chromatograms.