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Batteries

Physical Science - Middle School

 
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Batteries © Copyright NewPath Learning. All Rights Reserved. 94-4493 Visit www.newpathlearning.com for Online Learning Resources. Volta & th e 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. + Alessandro Volta (1745-1827) zinc Volta baery (voltaic pile) silver paper (soaked in salt water) + zinc electrode current wire electrolyte - sulfuric acid copper electrode terminals Wet cell + lead metal (-) lead oxide (+) sulfuric acid negative terminal positive terminal zinc electrode carbon electrode electrolyte paste negative terminal positive terminal Dry cell + + + Wet cell + lead metal (-) lead oxide (+) sulfuric acid negative terminal positive terminal zinc electrode carbon electrode electrolyte paste negative terminal positive terminal Dry cell + + + 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. 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.
Pause and Review Label the parts of the electrochemical cell. Batteries + Describe the difference between a wet cell and a dry cell. ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ © Copyright NewPath Learning. All Rights Reserved. 94-4493 Visit www.newpathlearning.com for Online Learning Resources.