Science, Grade 6


Table Of Contents: Batteries

1. Volta and the First Battery
Alessandro Volta, an Italian scientist who lived in the 1800s, developed the first battery. Volta hypothesized that a chemical reaction occurs between two metals and a salty fluid to create an electrical current. He soaked paper in salt water and placed it between zinc and silver. Then, when he connected wires to the pieces of metal, a current was produced. Volta had created the first battery, which was the foundation for modern electrochemical cells and batteries.
2. Electrochemical Cell
An electrochemical cell converts chemical energy into electrical energy. A cell is made up of two pieces of metal called electrodes. Often, these electrodes are made of copper and zinc. The electrodes are surrounded by a substance that conducts energy, known as an electrolyte. In this example, the electrolyte is sulfuric acid. The areas of the electrodes above the surface of the electrolyte are called terminals. A wire is connected to these terminals to make a circuit. Chemical reactions occur between the electrolyte and the electrodes, causing the electrodes to become positively and negatively charged. This difference in charges creates a voltage.
3. Wet Cells and Dry Cells
An electrochemical cell with a liquid electrolyte is called a wet cell. A car battery has a liquid electrolyte composed of sulfuric acid, and is an example of a wet cell. An electrochemical cell with a paste as the electrolyte is called a dry cell. A flashlight battery is an example of a dry cell.