Cells and Batteries An electrochemical cell can be used to generate a current without plugging into an outlet. The cell consists of two different metal pieces called electrodes.

The metals are in a solution, called an electrolyte which reacts with the metal to free up some electrons. The two eletrodes are kept seperated so that the electrons can move between them throught the soultion. When a wire is connected to each end of the cell, the electrons move through the conductor to get to the other side, creating a current through the conductor..

Electrons are always repelled away from the negative end of a cell and move through the circuit and into the positive end where they are attracted

When you connect several cells together, it is called a battery. Different voltages of batteries are created by connecting together different numbers of cells.

There are two types of batteries: primary and secondary

Electrochemical Cells Primary Secondary - Single use - Multiple use - Can be discharged but not recharged - Can be discharged and recharged - Only one chemical reaction - 2 chemical processes; one to discharge, one to recharge

List advantages and disadvantages of each Primary Secondary Advantage: - Has only one chemical reaction - Can be used multiple times Disadvantage: - Can only be used once - Has 2 chemical processes

Electric Circuits A controlled path of moving electrons is called a ciruit. In order for electrons to move, there must be a continuous, complete path between a positive terminal and negative terminal. This is called a complete circuit. If the path is broken at any point, then the circuit is called incomplete.

There are 3 major parts that all circuits need There are 3 major parts that all circuits need. These are the energy source, the path and the load. Most circuits also have a switch, though that is not always necessary.

Part of circuit Function Examples Energy Source Supply electrons Batteries, fruit, Path Transfer electrons Wire Load Converts energy into useful forms Bulb, motor, resistor, Switch Opens and closes the path Light switch