Beacon Lesson Plan Library

Molecules Rock

Mary Easley


This shows students that molecules of life move dynamically and powerfully. It's an interactive approach to teaching diffusion and osmosis.


The student knows that the body processes involve specific biochemical reactions governed by biochemical principles.


-Beakers (34)
-Task Sheet, Lab Setup, and Final Assessment (See Associated File)
-Bottle of perfume
-Potassium permanganate
-Cheesecloth (baggie-ize)
-Starch solution divided into 2 beakers (Try varying concentrations)
-Dialysis tubing
-Starch solution
-Beaker of water
-Elodea (12 leaves)
-Potato slices
-Enlarged pictures of blood cells submerged in hypertonic and hypotonic solutions
-Candy (optional)


1. Download and copy the Task Sheet and Final Assessment for the students. (See Associated File)
2. Prepare initial demonstration material--perfume and potassium permanganate and beaker of water.
3. Prepare starch solution and have cheesecloth and baggie ready.
4. Prepare all materials for dialysis tubing osmosis experiment--prepare starch solution; prepare 6 piece of dialysis tubing; prepare a beaker of water. You can actually set the experiment up in class to make it more effective. (See Lab Setup in Associated File)
5. Set up the demonstrations of the living components in differing concentrations the morning that you will use them. You can have 6 stations to make the lab run more smoothly.
6. Have bag of candy on hand. (optional)


1. Demonstrate diffusion by opening a bottle of perfume in class and allowing the odor to permeate to all parts of the classroom.

2. Demonstrate diffusion further by showing how potassium permanganate diffuses out into a beaker of water.

3. Discuss student observations.

4. Say and then write on the board the definition of diffusion.

5. Hand out Task Sheet (See Associated File) and explain its purpose and significance.

6. Demonstrate permeable membranes and semi-permeable membranes by using cheesecloth and baggies; use a starch solution and see what happens with both.

7. Discuss the results with students.

8. Now define osmosis.

9. Diagram three different osmotic concentrations on board and discuss how water would move from these into or out of a cell: the osmotic concentrations are hypotonic, hypertonic, and isotonic.

10. Ask students to think of and suggest examples of daily activities in which these processes would be operating.

11. Show the materials to be used in the osmosis experiment. (See Lab Setup in Associated File)

12. Put the procedure on the board.

13. Have students help you set the experiment up.

14. Results will occur almost immediately; you can have one setup done ahead of time to give students instant feedback or instant results.

15. Discuss the results with the class.

16. Have students join partners to fill out their Task Sheets on the experiment

17. Set up different stations (3 pairs altogether): Elodea cell with hypertonic solution, elodea cell with hypotonic solution; potato slice with hypertonic solution, potato slice with hypotonic solution; enlarged digital pictures of blood cells submerged in hypertonic solution and one with hypotonic solution.

18. Have students draw the differences seen in each station and record the information on their Task Sheet.

19. Then have groups of 4 students form and list the instances that osmosis operates in every day activities within plants and animals.

20. Reward the group with the greatest number of correct examples with something such as candy.

21. Review the entire Task Sheet for correctness as a class activity.

22. Tell students to study their Task Sheets for the Final Assessment.

23. Give students the Final Assessment (See Associated File) on the material covered in the lesson.


1.Students work on an ongoing Task Sheet that gives them an outline of all important class activities related to this topic.*
2. Students analyze lab outcomes orally and in writing. You should be careful to observe that students get the idea in the lab that water moves through the dialysis tubing to equalize concentrations.
3. Students complete the short-answer Final Assessment on the entire lesson plan.

*Assessment Tool: Provide the Task Sheet at the beginning of the instruction with the significant words and boxes for important in-class demonstrations. Explain to students that this sheet allows them to see all the expected outcomes for this learning activity and also provides them with a study sheet for the Final Assessment at the end.

Attached Files

This file contains the Task Sheet, Lab Setup and Final Assessment.     File Extension: pdf

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