This is a lesson which meets specification points within the WJEC GCSE ‘The Sciences’ Double Award (2026) spec, specifically from Unit 1.3 Systems (Biology).

The lesson starts with an introduction to the investigation. Transpiration is the evaporation of water from a plant’s leaves. This causes water to be taken up through the roots. In this investigation, it is assumed that the volume of water taken up by the roots is equal to the volume of water lost by evaporation from the leaves. A freshly cut plant shoot will be used to carry out transpiration. The rate of transpiration can be measured by recording the distance travelled by an air bubble along a capillary tube in a set period of time.

The next couple of slides outline the equipment needed and the method list for this investigation. Students will then ‘Think > Pair > Share’ their ideas about a results table should look like. After a class discussion, the teacher can draw some example tables on the board so students have an idea about what they need to include for their results table.

After this, in pairs/groups students should have another discussion about the control variables and potential sources of error in the investigation. Some examples for each of these are included in the PowerPoint for the teacher to go through.

Now, students can complete the investigation, recording their results as they go. Once complete there are a set of analysis questions for them to answer, based upon the results they have collected.

All resources are included. Thanks for looking, if you have any questions please let me know at swyftresources@gmail.com and any feedback would be appreciated.