|MadSci Network: Physics|
Hello, Tasia. I'll try to explain how a potato can be used to generate electricity.
The potato itself has a mixture of starches and salts and some water. A salt, like table salt, in water releases ions. Ions are atoms that have an electrical charge. Table salt releases two electrically charged ions - a sodium ion with a positive charge, and a chlorine ion with a negative charge.
To make a battery with a potato, you need to put two different metals into the potato...the metals can be zinc and tin, or copper and steel, or other choices. The point is - the two metals have to be different metals. You might use a penny (made of copper) and a nickel (made of...ummm...nickel).
The two different metals are different in many properties - color, density (how heavy they seem to be). They also differ in whether and how much they react with the electrically charged ions and electrons. When a metal reacts with a positively charged ion, like the positively charged sodium ion in the salt in a potato - the metal gets a bit of a positive charge.
Positive electrical charges and negative electrical charges attract each other. The positive charge in the metal will attract negatively charged electrons. The other, different metal, may have a negative charge, having reacted with the chlorine in the salt in the potato.
Electrons are the carriers for electricity. They also have a negative charge. If you put the two different metals, like a penny and a nickel, in the potato, and one of the metals gets more negative, and the other metal gets more positively charged - the potato battery is ready to conduct electricity. If you hook up a sensitive electric meter, or perhaps even a small flashlight bulb or electromagnet, by hooking up wire to each of the two metals in the battery - electrons will flow from the more negative metal, through the connection, to the more positivley charged metal. This flow of electrons is electricity.
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