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Flowing Electrons
Electric current is very similar to a flowing river. The river flows from one spot to another and the speed it moves is the speed of the current. With electricity, current is a measure of the amount of charge (or energy) transferred over a period of time. That stream of energy is a flow of electrons, or individual negative charges. Those electrons can move through the air, but they usually flow through conductive materials such as copper wire or a computer chip. Scientists use the value amperes when they measure current.
Current and Heat
One of the results of current is the heating of the conductor. When an electric stove heats up, it's because of the flow of current. The electrons have a mass (however small), and when they move through the conductor there is friction. That friction creates heat. The more electrons bumping into the atoms of the conductor, the more heat is created.
Scientists used to think that the flow of current always heated up the object, but with modern superconductors, that is not always true. Electrons can pass through and very little friction is created. Because there is less interaction with the molecules, the charges move faster and lose less energy.
Spaces Between Atoms
Everything that is matter can conduct electricity, but not everything does it well. Scientists use the terms conductors, insulators, and semi-conductors. The labels are used to describe how easily energy is transferred through the object. When you think of electric current, you probably think of conduction current. Conduction current happens when there is a transfer of charge by the movement of particles. The positive charges attract the negative charges. That attraction combined with the spaces between the atoms makes an object a good conductor or insulator.
Usable Current
There are two main kinds of electric current, direct current (DC) and alternating current (AC). They are easy to remember. Direct current is the energy you get from a battery. The charges move directly from one point to another. Alternating current is in the plugs of your walls. The big difference between the two is that DC is a steady stream of energy while AC flips back and forth. AC reverses the direction of the electrons, almost pulsing through the power lines.
Be very careful if you work with electricity. NEVER touch the plugs in your house. That electricity is very powerful and it can hurt you… badly. Electricity from batteries can also injure you. We have burned ourselves when working with batteries and electromagnets, so we know what can happen. To be safe, go get an adult to help you with any experiments.
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