5E40.25 - Lemon Battery
Demonstrate electromotive force using a lemon and electrodes of dissimilar metal.
Make sure the camera output is visible to the audience. One electrode should already be in the lemon. Stab the lemon with the second electrode, make sure the two electrodes do not touch each other. The multimeter should read slightly less that 1-V when both electrodes are in the lemon.
**This demonstration must be requested at least 24 hours in advance**
The internal chemical reaction within the "battery" between the electrolyte (citric acid) and the negative metal electrode produces a build up of free electrons called the anode. The chemical reaction between the electrolyte and the positive metal electrode produces an excess of positive ions at the cathode. The electrical pressure or potential difference between the positive and negative terminals is called voltage or electromotive force.