5F40.10 • Simple Battery

Photo of the Demonstration at the University of Texas at Austin.

top left image: no heat, top right image: with heat, bottom left image: with heat pressed down, bottom right image: potato battery setup.

Faculty Instructions:

• Setup 1
• Set the hot plate to a desired but safe temperature. Be cautious when using hot plate, it conducts quickly!
• Lay the thermoelectric generator on the edge of the hot plate. Ensure no wires touch the hot plate
• Allow the thermoelectric generator to heat up and the increased voltage will display on the multimeter
• To produce a greater voltage, you may press the thermoelectric generator against the hot plate.
• Setup 2.
• Pushing a nail and copper wire into opposite ends of a potato (bring your own!), it acts as a battery where voltage can also be measured.
• Setup 3.
• If faculty desire, with a couple more potatoes from home (bring your own!) they can be set up in parallel with light bulbs attached to show the current through the circuit.

Concept Conveyed:

• The thermoelectric generator converts temperature differences into electrical energy (Seebeck thermoelectric effect).
• The potato battery setup acts as a salt-bridge between the nail and wire.
• The voltage produced should start off relatively small >.02V and gradually increases as it sits on the hot plate (top right image) or rapidly increases if pressed against the hot plate (bottom left image).

Demo Staff Notes:

• Ensure alligator clips are plugged into multimeter and are attached to the respective ends of the thermoelectric generator.
• Provide faculty with hot plate and heat resistant gloves.

Last updated on March 7, 2023