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Energy Around Us
We're here to talk about the energy that interacts with the Earth. An old song says, "Love makes the world go 'round." They were wrong. Energy makes it all happen. Most of the Earth's energy comes from the Sun. The rest of it comes from deep inside the Earth. There's a huge ball of molten iron (Fe) in the center of the planet and it's very hot. The Sun is still much hotter than anything inside our planet is.
Radiation Isn't Always Dangerous
There's an important idea you should always remember when we talk about energy. Sometimes we will use the word radiation. When you think of radiation you probably think about nuclear power plants, bombs, and X-rays. Those are all types of radiation but more important to physical geography is the idea that all light is considered radiation. That means that everything from television and radio waves to something called gamma rays are all types of radiation. Think about the word/acronym LASER. The R stands for radiation, while a laser is just a souped-up flashlight. Think about heat. Most heat is actually infrared light being given off by an object. That heat is also radiation.
Where Do You Find Energy?
Energy descriptions and measurements change a little when physicists start looking at the world. Geographers look at general ideas of energy circulating through systems. Physicists see things in very specific quantities, not always as systems. If you apply a force to an object, you put energy into the system. Energy must be used to do work or accelerate an object.
You can also find energy in electricity, magnetism, kinetic energy, potential energy, springs and different states of matter. Energy is not something you can hold or touch. Energy relates to the power and effort of a force. As we said, energy can be found in many places whether it be the heat from the core of the planet or incoming radiation from the Sun.
Gases? What can they do? Well, gases are great because they can be compressed. When the pressure increases, the amount of stored energy increases. It's like the energy stored in springs, but different. Eventually that energy can be let out to do something (work). In your car are shock absorbers. Some shocks have compressed gas in the cylinders. The energy in those cylinders keeps your car from bouncing too much in potholes. Think about wind. Wind is caused because of pressure differences in the atmosphere. When the wind blows, it can do anything: turn windmills, help birds fly, make tornadoes, all types of work.
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