What Is Energy?
Energy makes things happen! It’s the ability to create change or do work.
Energy is involved in every physical process around us. Animals and people get their energy from the food they eat. Plants use photosynthesis to convert the sun’s energy into the food they need to grow. Energy makes our bodies move and grow and allows our minds to think.
All the vehicles, devices, appliances, and equipment we use require energy to function. Energy cooks our food, plays music, heats water, and lights buildings. Cars and trucks are powered by different fuels, such as gasoline and electricity. Much of the energy used in homes and businesses is generated from electricity at power plants.
Energy is an important concept in many scientific fields. In physics, it helps us understand motion and forces. In chemistry, we learn about energy’s role in chemical reactions. Can you think of other sciences where energy concepts are put to use?
The Many Forms of Energy
Energy comes in various forms that we use for different purposes:
Mechanical energy (also known as motion energy) moves objects from one place to another. You use mechanical energy when you kick a ball or ride a bicycle. Sound energy is a form of mechanical energy that is produced when a force causes vibrations in a substance.
Electrical energy comes from the movement of electrons through a conductor, such as a copper wire. (Electrons are parts of atoms, the tiny pieces that make up everything on Earth.) Lightning and static electricity are natural forms of electrical energy.
Radiant energy moves in waves. Sunlight, X-rays, and radio waves are forms of radiant energy. Radiant energy can move through space and does not require a medium to travel through; it can travel through a vacuum.
Chemical energy is stored in the chemical bonds that hold together atoms and molecules. A molecule is formed from two or more atoms bonded together. Digestion releases chemical energy stored in food. Burning fuels like wood, coal, and natural gas creates a chemical reaction that releases heat.
Thermal energy is created by moving atoms and molecules and is released as heat. You feel thermal energy when you snuggle under a warm blanket or sit by a campfire.
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Nuclear energy is stored in an atom’s nucleus, or center.
It is released when the nucleus splits into many pieces or when two nuclei are forced together to form a larger nucleus.
It’s amazing to think about how much energy is all around us and how we use it in different ways every day. Which of the forms of energy on this page are you using right now?
Electrical Energy Is Everywhere
People have learned how to transform energy from one form to another so that we can live more comfortably. Electricity is a very useful form of energy because it can be transformed into other forms of energy that we need, such as heat, light, sound, and motion.
Here are some examples of how electricity is transformed:
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Heat: Electrical currents cause heating elements in toasters and ovens to become hot through resistance.
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Light: Electrical current makes lights glow.
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Sound: Electrical signals make speaker cones vibrate to produce sound waves. We hear these waves as music and speech.
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Motion: Electricity powers the motors
that spin fans and move the wheels of electric scooters, skateboards, vehicles, and more.
Light-emitting diode bulbs (LEDs) convert electricity into light while producing minimal heat. They are different from incandescent, halogen, and even compact fluorescent bulbs, which waste more of their electricity making heat instead of light. Do you have any LEDs in your classroom or at home?