We’re wrapping up our discussion of the battery vs peanut, and though students are just about willing to accept that a peanut has almost twice as much energy as a battery, a large fraction of the class still thinks that the battery’s gradual release of energy over a long time might possibly allow its energy content to be greater.
So we did one more experiment to test this. We simultaneously measured the temperature increase of 80mL of water when heated by a burning peanut and a shorted battery.
Here’s the data
Of course, there are some other interesting observations that come up. Here’s what the battery looks like after 3 hours of immersion in water. Note that a battery not in a circuit looks almost identical to a new battery after being immersed in water.
Similarly, the terminals of the battery holder experience what looks like a chemical reaction as well.