Students’ age range: 16-18
Topic: Transport in Cells
Description: Students already that osmosis is the process by which there is a net movement of wáter molecules from an area of high wáter concentration to a low wáter concentration through a selectively permeable membrane.
Cell loses wáter in hypertonic solutions, cell contents move away from cell walls as vacuole shrinks. Cell becomes flaccid (limp). Cell gains wáter in hypotonic solutions, vacuole increases in size, pressing cytoplasm against cell walls. Cell becomes firm.
1. Introduction: Students placed in groups of threes and given a set of letters to unscramble to identify the topic of the lesson ‘Transport in Cells’.
2. Students will be shown a short video of an experiment demonstrating
Osmosis with instructions to listen and give unfamilar terms Heard in the video.
3. Discussion of unfamilar terms definition between teacher and students.
4. Students will use information gained from video and discussion to predict/infer the type of solutions in which each potato strip was in that was set-up beforehand.
5. Students will be given a table with the original length of potato strips at the start of the experiment to complete. Students will remove potato strips from solutions, dry and measure each strip and record measurements in table.
CHANGE OF POTATO STRIPS IN SALT SOLUTIONS
Solution in beaker
Initial potato strip length (cm) Final potato strip length (cm) Change in length (%) Inference
6. Students will use information to plot a graph.