Introduction to Power and Energy

“I’m out of energy. I need to recharge.” We’ve all used that phrase before. At the end of a long day, we get tired and need sleep.

But what is energy?

Energy is the ability to do work. It allows us to throw a baseball, carry groceries, and have a warm house even when it’s cold outside.

There are two types of energy: Potential and kinetic.

Potential energy is “stored” energy. It’s the energy waiting around to be put to work.

Kinetic energy is the “working” energy. It’s in motion getting used up.

Here’s an easy example: Picture a big rock at the top of a hill. When it’s sitting at the top of the hill, unmoving, it has potential energy. It has the potential to roll down the hill. When it does roll down the hill, it’s in motion. It’s using kinetic energy. As it rolls down the hill, the potential energy is converted into kinetic energy.

 So…how does energy get made?

Energy cannot be created or destroyed. It can only be converted from one form to another.

The energy that allows us to use appliances and lights in our homes comes from electricity, which is made in power plants.

Example: To demonstrate how much electricity people use on a daily basis, ask your child to think about all the appliances in the house, and how often they use them. How many appliances are there? How many light switches are in the house? This is a tangible way to show how much electricity (and energy!) we use on a daily basis.

Electricity comes from two main sources: Nonrenewable and renewable energy.

Most of the energy we use comes from nonrenewable energy sources. Nonrenewable means that we cannot use the energy over and over. Once we use it, it’s gone forever.

The way nonrenewable energy is gathered can be bad for the environment. Most nonrenewable energy sources are called “fossil fuels.” They are called this because they formed over millions of years.

Fossil fuels are coal, oil, and natural gas. Fossil fuels are burned in a power plant. At the power plant, steam is created from heat and water. The steam turns the turbine in a generator. This produces electricity.

The other type of nonrenewable energy is nuclear energy. Nuclear energy uses uranium atoms to power generators.

Some energy we use also comes from renewable energy sources. Renewable energy sources are:

  • Solar power (the sun)
  • Hydropower (water)
  • Geothermal (the Earth’s crust)
  • Wind power (wind)
  • Biomass (materials such as wood and corn)

Renewable energy can be used again, or renewed. Because of this, it solves a problem that nonrenewable sources cause. However, nonrenewable energy is usually cheaper.

All sources of energy — nonrenewable and renewable types — create energy and electricity that powers everyday things we use.

Power plants

Power plants are where electricity is created. They convert sources of energy, such as coal and oil, into electricity that powers your microwave.

Coal and oil plants burn fuel to release heat. That heat boils water and creates steam, which powers a turbine. Gas plants are similar, but they use a different type of turbine. Nuclear plants split atoms using fission to create heat.

On the other hand, a hydroelectric plant uses water instead of heat. The water powers water turbines to drive generators.

Back to electricity… how does that work?

Electricity is a form of energy that we use. A long time ago, before we had electricity, we used candles, wood-burning stoves and other basic ways to make food, provide light and keep ourselves warm. But electricity simplifies those tasks.

Electricity is the movement of electrons between atoms. Atoms are the universe’s building blocks; everything — us included! — is made up of atoms. They’re so tiny that we have to use a special microscope to be able to see them.

Atoms are made up of the nucleus, which houses protons and neutrons, and electrons. Protons have a positive charge. Neutrons are neutral. And electrons have a negative charge. Electrons spin around on the outer shells of atoms and are constantly shifting. This is electricity.

Energy is converted into electricity by generators.  Power plants use turbines to drive generators. There are varying types of turbines — steam, gas combustion, water (see “power plants” section for more information).

Fast Facts

  • In 2016, natural gas was the most common energy produced:
By fuel/energy source and share of total 
Natural Gas33%
Oil (e.g., crude oil and natural gas plant liquids)28%
Coal17%
Renewable12%
Nuclear10%

Statistics from the U.S. Energy Information Dept.

  • But by 2050, solar energy may be the world’s largest source
  • Renewable energy creates jobs 12 times faster than the rest of the economy
  • Ever wonder who found out about electricity? Benjamin Franklin is credited with the discovery by most people.
  • If a person yelled for 8 years, 7 months, and 6 days, he or she would produce enough energy to heat one cup of coffee.

Additional Resources

The following is a list of experiments, videos and tools for learning about power and the different types of energy.

Videos

How is electricity generated?

How does a coal power plant work?

What is the difference between renewable and nonrenewable energy?

Magic School Bus episode on energy

Worksheets

Energy sources

Potential vs. kinetic energy

Renewable vs. nonrenewable

Experiments

Kinetic and potential energy differences — These experiments allow kids a hands-on look at how potential energy is turned into kinetic energy,

Hydro power — This experiment is a simple look at how water can power things.

Other links

Energy for Kids — Simple explanations from the U.S. Energy Information Administration

How to save energy — We use a lot of energy. Here are quick tips for kids on how to save on it.

About Brian 69 Articles

Brian is an engineer, librarian, and general STEM enthusiast who hopes his daughter one day conquers the world. Even if it is just one of her own creation.

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