Where can you find energy?
Picture yourself sitting by the campfire. You and your family are using the fire to stay warm on a chilly evening. As the Sun goes down, the air gets colder. You move closer to the fire. Heat from the fire warms you. Light from the fire allows you to see your relatives. Maybe you put marshmallows on a stick and roast them. Yum.
What Is Energy?
What explains all of these events? The answer can be summed up in one word: energy. Energy is defined as the ability to do work. Doing anything takes energy. A campfire obviously has energy. You can feel its heat and see its light. You can use its energy to cook food.
Forms of Energy
Heat and light from the campfire are forms of energy. There are many other forms of energy. Here are a few that are important in Earth science:
- chemical energy: Energy that is let off after a chemical reaction.
- luminous energy: Also called light.
- nuclear energy: Energy that is let off when the atom of a nucleus is split.
- radiant energy: Energy of electromagnetic radiation. This is the topic of the concept "Solar Energy on Earth."
- sound energy: Energy from sound waves.
- thermal energy: Also called heat.
Conservation of Energy
Energy cannot be created or destroyed. It can change form. For example, a piece of wood has chemical energy stored in its molecules. When the wood burns, the chemical energy changes to thermal energy and light energy.
Lightning converts electric potential energy into three kinds of energy. They are light energy, sound energy, and thermal energy.
You convert chemical energy in food to movement (Figure below). That's another way energy is transferred from one form to another!
If the girl eats this apple it will provide the energy needed for her to run.
Movement of Energy
Energy can move from one place to another. It can travel through space or matter. That’s why you can feel the warmth of a campfire and see its light. These forms of energy travel from the campfire to you.
Science Friday: Forecasting the Meltdown: The Aerial Snow Observatory
75% of Southern California's water supply comes from the snowpack in the Sierra Nevada Mountain Range. This video by Science Friday explains how NASA uses specialized instrumentation in the Airborne Snow Observatory to carefully measure the water content.
- Energy is the ability to do work.
- Energy cannot be created or destroyed. Energy can only change forms.
- Energy can change from one type to more than one type. For example, electric potential energy before a lightning strike can turn into light, sound, and heat.
- What is energy?
- How does energy change from one form to another?
- Figure out two examples in your life of when energy changes from one form to another.