Danita Burleson, age 12, of High Point, North Carolina, for her question:

What is inside a battery?

Its purpose is to create an electric current from chemical activity. And chemicals that are capable of this sort of activity also are capable of. other things. They are strong enough to corrode many tough substances and certainly strong enough to burn living tissue. So, let's beware when it comes to examining the stuffing inside a battery even when the snappy little worker seems to be quite dead.

Household current is generated by whirling generators and it must be carried from there to here in an unbroken wire circuit. Handy outlets are needed to plug into the power supply. When we want to turn on a radio or start a car engine out there on the open road, these outlets to the main power supply are unavailable. This is when we need a combination of activated chemicals, tightly sealed inside a sturdy shell.

All electric current is created by streams of moving electrons. A big generator boosts them through a wire circuit by voltage pressure. A battery produces current by exchanging electrons between two solid substances. The action is triggered by acid chemicals, either in a moist paste or dissolved in water. Various chemical ingredients are used in different type batteries.

Car batteries contain a liquid solution of water and sulphuric acid. The sturdy little batteries that power flashliphts and portable radios are packed with a paste that may contain granulated carbon, graphite and sal ammoniac, manganese dioxide and zinc chloride. The mixture is moistened with water. Other batteries may contain separate solutions of zinc sulphate and copper sulphate, or a solution of potassium hydroxide.

These various acid chemicals act as electrolytes, which trigger the action. They work on two plates called electrodes by shifting electrons from one to the other. One electrode tends to shed electrons into the electrolyte, the other tends to attract them. Electrons are negative particles and normal substances have enough of them to equal their positive protons. Hence, they are electrically neutral.

But one electrode in the battery loses electrons. This reduces its negative charge and makes it positive. The electrode that pains extra electrons gets a surplus negative charge. Battery electrode plates may be zinc and carbon, zinc and copper, nickel and cadmium or just lead.

The paste or liquid electrolyte must be in contact with the opposite electrodes to start the chemical action and shift the electrons. These streams of electrons are led off through a wire circuit as direct current. One end of the wire is attached to the negative electrode and the other to the positive electrode. Plus and minus signs are placed on the two contact points.