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# A Source of Energy by Kathi Wagner and Sheryl Racine

Did you ever wonder what it would be like if we didn't have the sun? Have you ever noticed how much cooler it is at night (when the part of the earth you are on is not facing the sun) or when it rains for several days? You probably enjoy snow days when you can build snowmen, but when the ground is covered with snow, the sun's light can't reach the ground, which means the sun's energy is unable to be used and instead of heating the earth, it travels back out toward the universe. We need the sun's energy to grow food, heat our planet, and give us light.

Have you ever heard of the scientist Albert Einstein or his famous formula, E=mc2? He used the letter ‘c’ in his equation to represent the speed of light. So if you take the speed of light (186,000 miles per second) times itself (186,000) or squared, it equals around 35 billion. He believed multiplying the mass of an object, (in this case, the sun's gas,) by c squared (c2) (the speed of light times itself) revealed the amount of energy that was developed. When you multiply even a little mass by such a large amount, you have a lot of energy! By calculating all of this information, Mr. Einstein figured out that the hydrogen in the sun would be able to keep the world warm for a very, very long time. You can see the sun's energy in full force in the summer time. It's easy to see how hot the inside of a car is if it sits out in the sun, especially if the seats are dark-colored. For years people have been trying to find different ways to use the sun's energy and warming power. Some people use solar panels mounted on their roofs to let the sun warm their house. Can you think of other ways to use the sun's energy? Food is made from energy collected from the sun. Even petroleum products and coal were made from plants that used the sun's energy to grow many, many years ago! Sun warms the waters in the ocean to grow plants to feed the plankton that feed the littlest fish to the biggest ones. If you want to see the sun's energy at work, how about planting a sunflower? Just follow these easy steps:

• First you will need a large, sunny garden spot.

• Once you have located your spot, loosen the soil a few inches deep.

• You will need sunflower seeds meant for planting.

• Plant the seeds a couple of inches deep.

• Water your seeds at the time you plant them, and then as needed, allowing the ground to dry a little between watering.

• When your sunflower is several feet tall, watch to see what the flower does as the sun crosses the sky.

## Sitting in the Sun

On sunny days, you can sometimes find a turtle resting on a log above the water, a cat curled up on a windowsill, or a snake stretched out on a rock. What all of these animals have in common is they are warming themselves in the sun. Humans, like other animals, also like to be in the sun. Every summer you can see people flocking to the beach, hoping to catch some rays. Not only does the sun's warmth feel good, but small amounts of sunlight can also help to keep you healthy. One of the things people get from the sun is called vitamin D. To help everyone stay healthy, many companies add vitamin D to their milk and orange juice just in case you miss your daily dose of sunshine!

Have you ever counted the colors in the rainbow? These colors are the parts of the light rays that you can see, but the unseen light rays, called ultraviolet or UV, are the ones that burn your skin and cause sunburns. So, if you are going to be out in the sun for a while and you don't want to wind up red as a beet, you will want to put on some sunblock (also known as UV sun blocking lotion). It is important to keep applying it, especially if you go in and out of the water. Another way to help prevent burning is to stay out of the sun during the hottest part of the day (which is usually early to mid-afternoon).

## LUNAR:

The word lunar means of or about the moon. Many calendars are based on the time it takes for the moon to travel around the earth. This time is called a lunar month.

## Around and Around We Go

Start at the very center of our solar system, and travel out to the farthest edge. Be sure to visit all eight planets, and the dwarf-planet, Pluto!

## Sun-sational Things

You have probably seen lots of rainbows; especially if you have learned when and where to look for them. It is easy to spy them right after a rain, if it rains in the morning not too long after the sun comes up or in the evening right before the sun goes down. Do you know what causes the brilliant colors? It's the sun shining through the moisture in the air after the rain has stopped. Another fun thing to watch for is sundogs, which look like colored lines curved around the sun when it is not too far above the horizon. Sundogs get their color from the ice particles that are floating in the air.

There are so many unusual and spectacular things to see. One example would be if you climbed up a mountain and stood on top of it; you might have seen a silhouette of your head on the clouds below you. The only way this could happen was if the sun was shining on your back and if the clouds below were filled with rain. Then your head's shadow might have a halo surrounding it, just like the moon does at times. These strange sightings called “the glory” are very rare. You can increase your chances of seeing this if you are ever flying in a plane and sitting in a window seat away from the sun. If you watch closely you may see the silhouetteof your plane on the clouds below, with colored rings completely encircling it!

## JUST for FUN

It Was So Hot!

Maybe you have heard the expression “It was so hot, you could fry an egg!” Depending on the surface and where you live, sometimes you could. To see how hot the sun can make some things, lay a dark sock and a light sock in the sun. After ten minutes, check to see which one feels warmer. Which color of clothing do you think would keep you cooler?

## Try This

If you don't want to have to wait until the conditions are just right to see a rainbow in the sky, turn on your water sprinkler to send waves of water back and forth through the air. Make sure the sun is shining behind the water, and start watching for the rainbows to appear in the moving water.

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#### THE EVERYTHING KIDS' ASTRONOMY BOOK

By Kathi Wagner and Sheryl Racine

1. Home
2. Astronomy for Kids
3. The Sun, the Center of Our Solar System
4. A Source of Energy