Biology / Science GCSE: Investigate osmosis in plant tissue
This video demonstrates the GCSE Biology and Combined Science required practical to investigate osmosis in plant tissue, included in both AQA and Edexcel specifications.
Osmosis is a challenging concept, and this investigation is also challenging in terms of the manipulation, organisation and number of practical skills needed. This video helps to ensure the concept itself is understood as well as how to generate and interpret the data collected.
This practical supports Development of Apparatus & Techniques Biology 1, 3 and 5 (DfE GCSE subject content guidance, Appendix 4).
Osmosis and concentration are both challenging and abstract concepts. Osmosis does not feature in the KS3 programme of study and so may be a new concept at KS4.
Using this video in chunks could help to create understanding of these principles before moving on to explaining the data and observations. Having a secure understanding of osmosis and concentration will help students to explain observations of increasing and decreasing mass in plant tissue.
Following the investigation by students, this video can reinforce how to manipulate and interpret the data generated and how to make improvements to increase accuracy and validity.
Points for discussion:
This video is used to explain the science behind the required practical, before focusing on analysis of the data produced and then suggesting ways to improve accuracy of the data.
It is important that students understand the concept of osmosis and how the process is affected by concentration in order to explain the observations in the investigation.
Students often find it challenging to suggest specific ways to improve the outcome of a required practical. This video explores how to change the range of measurements to increase accuracy of prediction and also explains why repeating measurements can be useful.
Students could practise manipulating unfamiliar data from similar investigations, calculating percentage change and analysing what is a relatively difficult graph.
Students could design an improved investigation, applying what is suggested about narrowing the range of concentrations investigated.
Allowing students to investigate osmosis in different tissues, or to see data involving other tissues, could help to dispel any misconception that osmosis is specific to potato cells.
Suitable for teaching Biology and Combined Science at Key Stage 4 and GCSE in England, Wales and Northern Ireland, and at National 4 and 5 in Scotland.