About This Lesson
Objectives for Learning
Students will be able to:
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Define electricity.
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Explain where we get electricity
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Understand the relationship of current and charge to electricity.
Summary
Energy from electricity is introduced to the students. Students learn how charge, and current relate to each other. They learn how to form a circuit and which materials conduct electricity. They find that their lights, heat, toys, TVs, and other home appliances work because electricity is generated at a power plant and directed through switchboards to parts of their home.
Lesson
Turn the classroom lights on and off several times to get the class's attention. What makes the light give light? That's right, electricity or electrical energy. Can you see electricity? No, you can see the product of electricity like the lights in the classroom. Can you feel electricity? Yes, lightening, wall outlets, and static can shock you and give you a jolt that you can feel. Can you smell electricity? No, it has no smell of its own. How about hearing electricity? You can hear a buzzing from some components that are powered by it, but it has no sound all by itself.
Electricity is made of little parts of an atom. Everything in the world is made of atoms. The center of an atom is called a nucleus. Inside the nucleus is a particle called a proton which has a positive charge. Around the nucleus are other particles called electrons that have a negative charge. A balanced atom has the same amount of negative electrons matched up to the number of positive protons. If an atom loses some of its electrons it will try to attract other electrons from somewhere else to balance out the protons. The force of those electrons being drawn to the protons is called an electrical force.
When an atom has more negative electrons than positive protons, it is called a negatively charged atom or ion. When an atom has more protons than electrons, that atom has a positive charge and is called a positive ion. Negative ions will naturally try to get rid of the extra electrons it has and send them to a positive ion. When electrons flow from a negative ion to a positive ion, that flow is called a current. Think of a game of catch. If you have a baseball mitt, you want a ball to be thrown into it. A mitt is a proton and a baseball is an electron. A boy or girl with a mitt and no baseball is a positive ion. A boy or girl with a mitt and 2 baseballs is a negative ion. When the player with the 2 baseballs throws the extra baseball to another player, that throw is like an electrical current.
Power plants burn fuels like coal and oil to create steam that spins large wheels with blades called turbines. The turbine spins a magnet and as the magnet spins, electrons are sent out for the first half of the spin and then are sent back on the second half of the spin. This motion always keeps the electrons moving in alternating directions or making and alternating current of energy. If we go back to our game of catch where you have two players with mitts and only one baseball, then the baseball has to be thrown back and forth from one mitt to the other creating a current (and a lot of fun).
So the power plant creates an alternating current of energy that travels back and forth to your home. Each home has a switchboard that directs that current to different parts of your house to power lights, cell phones, televisions, and air conditioners.
Vocabulary
alternating current: Electric current that reverses its direction many times a second at regular intervals, typically used in power supplies. Abbreviated as AC.
current: Movement of positive or negative electric particles (such as electrons) accompanied by such observable effects as the production of heat, of a magnetic field, or of chemical transformations
electrical energy: Energy made available by the flow of electric charge through a conductor
electron: Very small, negatively-charged particle.
energy: The ability to do work.
proton: Very small, positively-charged particle.
