Energy - Definition, Examples, Quiz, FAQ, Trivia
Discover how energy powers our world and learn about different energy types
What is Energy?
Energy is what makes things happen! It's the ability to do work, create change, or make things move. Everything that moves, grows, or changes uses energy. When you run, jump, or even think, you're using energy!
Think of energy as the invisible force that powers everything in the universe. It comes in many different forms and can change from one form to another. Energy cannot be created or destroyed - this is called the Law of Conservation of Energy. It just transforms from one type to another.
Energy Fact!
The food you eat contains chemical energy that your body converts into the energy you need to move, think, and grow!
Different Types of Energy
Energy comes in many different forms. Here are some common types of energy we encounter every day:
Kinetic Energy
Energy of motion - anything moving has kinetic energy
Potential Energy
Stored energy ready to be used - like a roller coaster at the top of a hill
Solar Energy
Energy from the sun that powers life on Earth
Chemical Energy
Energy stored in food, batteries, and fuels
Electrical Energy
Energy from moving electrons that powers our devices
Thermal Energy
Heat energy - the motion of atoms and molecules
Energy Measurement
Scientists measure energy in units called Joules (J). A small apple held one meter up has about 1 Joule of potential energy!
Energy Conversion
Energy is constantly changing from one form to another. This process is called energy conversion or energy transformation. Here's how energy transforms in everyday situations:
Flashlight
Chemical → Electrical → Light + Heat
Car Engine
Chemical → Thermal → Kinetic
Solar Panel
Solar → Electrical
Photosynthesis
Solar → Chemical
Human Body
Chemical → Kinetic + Thermal
The First Law of Thermodynamics tells us that energy is never created or destroyed - it only changes form. When energy transforms, some energy is always converted to heat that spreads out into the environment.
Energy Efficiency
No energy conversion is 100% efficient. In a light bulb, only about 10% of electrical energy becomes light - the rest becomes heat!
Energy Sources
We get energy from many different sources. These can be divided into two main categories:
Renewable Energy
Sources that won't run out: Solar, Wind, Hydro, Geothermal
Non-renewable Energy
Sources that will run out: Oil, Coal, Natural Gas, Nuclear
Renewable energy comes from natural sources that are constantly replenished. Solar panels convert sunlight to electricity, wind turbines use moving air, and hydroelectric plants use flowing water. These sources are better for the environment because they don't produce pollution.
Non-renewable energy comes from sources that took millions of years to form and will eventually run out. Fossil fuels like coal, oil, and natural gas release carbon dioxide when burned, contributing to climate change. Nuclear energy produces powerful energy from atoms but creates radioactive waste.
Global Energy Use
About 80% of the world's energy still comes from fossil fuels, but renewable energy is growing fast every year!
Energy Quiz
Test your energy knowledge with this quiz! Answer all 5 questions to see how much you've learned.
Frequently Asked Questions
Here are answers to some common questions about energy:
Energy Trivia
Discover some amazing facts about energy!
Solar Powerhouse
In just one hour, the sun provides enough energy to power the entire world for a year! Solar energy is the most abundant energy source on Earth.
Human Energy
An average person at rest generates about 100 watts of power - enough to light a bright light bulb! During exercise, this can increase to 1000 watts.
Lightning Power
A single lightning bolt contains about 5 billion joules of energy - enough to power a typical home for more than a month!
Energy Efficiency
Only about 20% of the energy in gasoline actually moves a car forward. The rest is lost as heat through the engine and exhaust.
