Energy is all around us. Energy can be classified as potential or kinetic. Potential energy is stored energy. Kinetic energy is moving energy. There are many types of potential and kinetic energies. Electrical energy is a type of kinetic energy because it is the energy of moving electrons.
Electrical energy comes from the flow of electrons. The faster the electrons move, the more electrical energy they have. Lightning, batteries and power lines are all examples of electrical energy.
Before you can understand electrical energy, you have to understand atoms. Atoms are the building blocks of all matter in the universe. Everything is made up of atoms. All atoms have a central nucleus. The nucleus contains positively charged protons and neutrons with no charge. Negatively charged electrons orbit the nucleus.
Electrons orbit the nucleus because the negative electrons and positive protons of the nucleus are attracted to each other. However, sometimes electrons leave the nucleus. The electrons of different elements behave differently. Some electrons rarely leave the nucleus while others move around. Elements with electrons that move around are called conductors because they conduct electricity. Elements with electrons that don’t move around are called insulators. Insulators do not usually conduct electricity.
Plastic, paper, rubber, glass, and air are all examples of insulators. Electrons do not usually leave the nucleus of insulators, but they can. Lightning moves through an insulator when it travels through the air.
Lightning is formed when electrons leave their nuclei in clouds. Scientists don’t know why this happens. They believe it has to do with collisions between air, water, and ice molecules in the cloud.
Once the electrons and nuclei are separated, the positive charges move to the top of the cloud, and the negative charges move to the bottom of the cloud. Over time, the charges get so big the atoms on the ground are affected. The negative charge at the bottom of the clouds pushes the electrons on the ground away from their nuclei.
The air molecules around the cloud are also affected. Air is usually an insulator that doesn’t allow electrons to leave their nuclei, but the negative charge at the bottom of the cloud pushes the electrons in the air away from their nuclei. The moving electrons create ions. Ionized air is also called plasma. The plasma forms a path to the ground that connects the negatively charged electrons in the cloud and the positively charged nuclei in the ground.
The movement of the electrons from the cloud to the ground is electrical energy. The electrons are moving fast, and they are releasing intense heat. A lightning strike is hotter than the surface of the sun. Heat causes air molecules to expand. As a result, these air molecules release photons. You can think of photons as particles of light. The photons are the bright flash of lightning.
Humans can’t control electrons during a lightning storm, but we have learned to use the movement of electrons to make our lives easier. By forcing electrons to move along copper and aluminum wires, we can use electrical energy to power our homes.
Humans start the flow of electrons at power stations. First, a fuel source such as coal or natural gas is burned to release heat. This heat boils water until it becomes steam. The steam is used to spin a turbine surrounded by magnets.
Magnets are a special kind of metal. Usually, the charges within an object are spread out, so they balance each other. In magnets, all of the charges are lined up, so one of the magnet has a negative charge, and one end of the magnet has a positive charge. The alignment of the positive and negative charges of the magnet creates a magnetic field. A magnetic field will pull electrons away from their nuclei.
A coil of copper wire is inside the power plant turbine. When the turbine spins within the circle of magnets, the electrons in the copper wire start to move. This movement is electrical energy.
The electrons travel from the power plant through transformers to your home. Transformers decrease the speed of the electrons, so you won’t get hurt using the electrical energy in your home. The faster electrons move the more energy they have, so it is crucial to slow electrons down before they come into contact with people.
At home, when you turn on a light or plug something into an outlet, you are completing a circuit, so electrons can travel through the wires and do work.
An electrical circuit is the path electrons follow. Electrons will only move along a closed circuit because they are moving away from a negative charge and towards a positive charge. If a circuit is open, electrons can’t move toward a positive charge, so they won’t move.
We can use the electrical energy of electrons moving through a circuit to power appliances in our homes. Electrons move easily through copper wires, so they don’t bump into many other atoms while they move. However, if the electrons are forced to travel through another type of metal such as nickel, they cannot move as easily, and they will bump into many other atoms. Every time the electrons and atoms collide thermal energy is released in the form of heat. The metals in toasters and electric heaters slow down electrons to convert electrical energy into thermal energy.
Light bulbs also convert electrical energy into heat energy. Initially, light bulbs used a tungsten wire to slow down electrons and increase collisions between electrons and atoms to convert electrical energy into thermal energy. The tungsten wire held so much thermal energy the atoms that made up the wire released light particles called photons.
Today, LED light bulbs use a different method of converting electrical energy into light energy. Converting electrical energy directly into light energy does not release as much wasted thermal energy as other light bulbs, so LED light bulbs are more energy efficient than other light bulbs.
Electrical energy is simply the energy of moving electrons, but humans have learned to use this energy to make our lives both more comfortable and entertaining.