Do You Know？（10）

A battery can be made out of a potato.

It is likely most kids will find it difficult to believe that a simple potato can make electricity to power a light bulb. However, the explanation is relatively simple. A potato contains sugar, water and acid. Certain types of metals – particularly copper and zinc – react with the potato when they are inserted inside. The metals effectively become electrodes, one positive and the other negative, and electrons flow between the metals inside the potato, making a small electric current. You can tap into the electricity by connecting wires from the electrodes to a light bulb to form a circuit. The electrons flow from the positive electrode to the light bulb and back to the negative electrode. The electrical current passing through the light bulb is enough to make it illuminate.

文章来源：https://sciencing.com/potato-light-bulb-experiment-kids-12105514.html

图片来源：百度图片