Lesson 2: Electric Fruit
Objectives: The students will be introduced to redox reactions.
The students will also recognize electrical conductivity as a property of acids and bases.
Standards Addressed by lesson:
Concept: Acids are good conductors of electricity. Bases also conduct electricity but poorly.
Exploration: Make a Lemon "battery". Use 3 lemons. Using galvanized copper and zinc wire connect the lemons to each other. Hook a multimeter to the lemons to measure the electric current. Plug a LED alarm clock into the lemons using the wires. Repeat with another item.
Data Collection: Record observations and organize multimeter readings into a chart.
Concept Introduction:
Application Activity: Cut an apple using a knife. Why does the apple turn brown? (redox reaction with the air)
History: Video Supplement (JChemEd)
Websites:
References:
Swartling, D.J. and Morgan, C. 1998. Lemon Cells Revisited- The Lemon-Powered Calculator, Journal of Chemical Education.2, 75, 181-182.