What is Solar Energy? - Definition, Pros & Cons

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  • 0:06 The Sun
  • 1:20 Solar Energy
  • 3:24 Pros and Cons of Solar Energy
  • 5:45 Lesson Summary
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Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

Learn about solar energy and how charged particles from the sun travel to Earth to provide heat and light. Explore solar energy as a direct and indirect energy source and examine the pros and cons of harvesting solar energy for other uses.

The Sun

Imagine you are a vibrating particle coming off of the sun - a super-tiny speck of energy called a photon. You travel from the sun out toward the rest of the solar system. You and your other photon friends band together to form electromagnetic waves, which are waves of energy having a set frequency within the electromagnetic spectrum, as seen here. The frequency of your waves determines what type of electromagnetic energy you are, and because you came from the sun, you fall in the middle of the electromagnetic spectrum. This means that you and the other photons are specific types of electromagnetic energy, called infrared, visible and ultraviolet light.

Waves within the electromagnetic spectrum

Since you are a particle of light, you travel at the speed of light, and it takes you and your buddies in the same electromagnetic wave about eight and a half minutes to make the 93 million mile journey to Earth. When you and the other photons bump into atoms, it causes some of the electrons from those atoms to jump around, giving off energy that can be harnessed for many uses here on planet Earth. Let's take a closer look at the sun as a source of energy.

Solar Energy

The sun is a star one million times the size of Earth. That means if Earth were the head of a pin, the sun would be roughly the size of a basketball.

The sun is also a very hot ball of gas. Its surface is about 6,000 degrees Celsius, and the sun gets even warmer the further you travel toward its center. This is because a process, called nuclear fusion, takes place at the center of the sun. Nuclear fusion is what happens when small nuclei are fused together to form heavier nuclei. The process requires a lot of heat, which is why the sun is an ideal place for it to occur. This process also generates a lot of energy. You can recall this term by noting that the word 'nuclear' refers to the nucleus of an atom, and the word 'fusion' refers to joining or fusing of objects together. So 'nuclear fusion' is literally nuclei fusing together in the extreme heat of the sun, resulting in the release of massive amounts of energy.

Energy is the ability to do work, and 'solar' is a Latin word for the sun. So, we can define solar energy as energy obtained from the sun. We can put this energy to work for us in many ways, from heating water and living spaces within our homes to generating electrical energy. Solar energy is a type of radiant energy, so named for the vibrating particles 'radiating' from the sun that we talked about earlier. Solar energy is sometimes called solar radiation for this reason.

Solar energy also does other kinds of work that is more indirect. Plants use the sun's energy through the process of photosynthesis to grow, and, more indirectly, we eat plants like fruits and vegetables to provide our bodies with energy. The sun is such an important part of life on Earth that it's not surprising that so many end-of-the-world science fiction movies begin with the sun not doing its job properly.

Pros and Cons of Solar Energy

There has been a lot of talk lately about using more renewable energy, or sources of energy that can replenish themselves, like wind, solar and hydroelectric power. Unlike carbon-producing fuel sources, like coal and oil, we can depend on renewable sources, like the sun and wind, to continue to provide energy without ever being depleted or running out.

If we could capture all of the sunlight that shines on the Earth in just one hour, we could supply the world with energy for an entire year. On a smaller scale, a simple three-foot by three-foot patch of earth located in a sunny area gets about 2,000 kilowatt hours of solar energy over a year's time.

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