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.
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 speed 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.
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.
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.It makes sense, then, that we try to use this widely available, renewable energy source. Another perk that makes solar energy a desirable energy source, is the fact that it does not produce greenhouse gases, such as carbon dioxide, which is a gas in the atmosphere that traps heat and is thought to contribute to global climate change.
However, solar energy is not a slam-dunk when it comes to supplying the world with energy. We lose a lot of energy through the process of collecting solar rays, and the technology is still quite expensive.Currently, we can only gather about 15 to 20 percent of the energy available from the sun.
While scientists are working on perfecting solar cells that can collect the sun’s energy and convert it to electricity, solar cells are still quite expensive, from materials, to installation, to maintenance. To add to the challenges of solar power, it’s important to note that there are many places on Earth that are not consistently sunny. There is also the pesky problem of the sun only shining during the day and not at night, and because solar energy is hard to store, there is often a need to back up solar power with other energy sources.
There are some interesting prospects for solar energy on our horizon. For instance, we have had solar-powered cars for several years, but they’re still too expensive to make available to a large number of drivers. And, like electric cars, solar-powered cars are limited by short battery life and access to consistent sunshine.
Still, scientists continue to seek ways to make solar energy a more viable and efficient option.
Let’s review. A photon is a speck of energy that comes from the sun. Many photons band together to form electromagnetic waves, which are waves of energy that move toward the Earth and provide heat and light.Solar energy is a type of radiant energy that travels in waves from the sun to other parts of the solar system. Most life on Earth, from humans to plants, relies on solar energy directly or indirectly.
Since solar energy is a renewable resource that is not depleted when used, scientists continue to develop ways for us to capture solar energy and convert it into usable energy. For instance, solar cells are an example of how we can collect the sun’s energy and convert it to electricity.Although the sun generates a tremendous amount of energy, solar energy has some drawbacks. Much of the energy from the sun is lost when we try to capture it, and solar cells that are used to convert solar energy into electricity are expensive. Also, solar energy is not easily stored, so when the sun is not shining, the energy source is not available.
Upon completion of this lesson, you should be able to:
- Define photon, electromagnetic waves, and solar energy
- Understand how life on Earth depends on solar energy
- List the advantages and concerns regarding the use of solar energy