This The Ratio of Surface Area to Volume lesson plan also includes:
Demonstrate the ratio of surface area to volume in your high school class by using phenolphthalein, gelatin, and an onion. Intrigue the class by leading a discussion on osmosis and diffusion, then making "scientific jello." Participants note the changes before and after the addition of sodium hydroxide.
- Relate the activity to an organ system in the body, such as the urinary system and kidney function
- Phenolphthalein is flammable and may explode; take proper care and ensure participants follow all safety measures
- Class members should complete "The Parts of an Experiment: Introduction to Inquiry and the Scientific Process" prior to this activity
- Multiple parts of this activity allow time in between to discuss results and answer any questions before moving to the next phase
- Participants can design an experiment, as an extension to this activity, to demonstrate the effect of surface area on diffusion using starch and iodine