Potatoes have stored chemical energy which in return can be converted to electrical energy that can power a small light bulb or run a clock. Potatoes are composed of starches, salt and water.
Potatoes contain a lot of water, and thus have a high specific heat capacity. They are also rather dense (basically a solid blob of carbohydrates), which doesn’t allow heat from the center to dissipate as quickly.
How do Potato batteries work?
These two metals when inserted into a potato can create a chemical reaction that generates electric current or kinetic energy (electricity) to flow. Wires are then connected from the zinc and copper metals to a small light bulb to complete the electrical circuit and allow the electricity to flow thus resulting in potato batteries.
So, how do you conduct electricity in a potato?
One answer is, potatoes are a mix of starch and salts. Electric current is conducted between two metals inserted in the potato by forming a salt bridge between them. This occurs because the salt in the potato releases ions, allowing them to travel through the wire connecting the two metals [sc:1] [sc: comma] [sc:2].
You should be asking “How is electricity produced between potato and salt?”
I learned electricity is produced when two different metals are inserted between the potato and a salt bridge is created. The salt bridge is formed as salt releases ions which flow from one metal to another generating an electrical current.
Why do baked potatoes stay hot for so long?
Because potatoes are so dense and it takes a while for heat to escape them. Also baked potatoes have no opening so the heat just stays trapped inside the potato until you cut it open. That is why baked potatoes don’t steam until you open them.
A baked potato is pretty close to that shape. (If you find a spherical baking potato, it will stay hot even longer!) French fries have much more surface area for any particular volume and cool off faster. BTW, if you heat potatoes in an oven, the heating is through the surface.
How long does it take for a baked potato to cool?
How long it takes a potato to cool depends on its shape. A baked potato cools off more slowly than french fries. That’s because the total heat is proportional to the volume and the heat loss occurs at the surface. A sphere has the minimum surface to volume ratio of any 3D shape. A baked potato is pretty close to that shape.