We are surrounded by light every day. Explore various sources of light around your house and yard with your children to help them understand what light is and how it affects our daily life. You may want to start by asking questions about the differences between light and darkness, and then go on to investigating light.
Most light comes from heat. When something gets very hot, it usually gives off light. Some examples are a campfire, a stove burner, and the flame of a candle. They all produce heat and light! The largest and most important source of light we have is the Sun. (Read more about that below.) Most lights that we use come from electricity and light bulbs.
No, some kinds of light do not come from heat. Some examples are the light inside a firefly and the light in a television. Can you think of more?
Light always travels in a straight line for as long as it can. When it hits something that it can't go through, like a wall or a piece of cardboard, the light goes in a different direction. When you turn on a lamp in your room, light rays from the light bulb spread out all over the room and light it up so you can see.
The sun is the biggest, brightest, and hottest source of light available to us on the earth. Did you know that the sun is actually a star? The outside of the sun (its surface) is covered with very hot gases. The different gases mix together and cause reactions that are called nuclear reactions. Nuclear reactions create a lot of energy, which makes the sun very hot. The heat creates a lot of light too. Did you know that the sun is so bright that it will damage your eyes if you look directly at it? The light from the sun can also hurt your skin. Have you ever had a sunburn? Although sun rays can hurt our bodies if we aren't careful, nothing would be able to live on the Earth without the energy (in the forms of heat and light) we get from the sun! Click here to see a close-up picture of the Sun from NASA.
Questions and answers about the sun:
Our sun is about 1.4 million kilometers in diameter (across its middle)! That is 109 times as big as earth.
To help your kids understand how big the sun is compared to the earth, help them count out 109 Cheerios and then line them up in a straight line on the floor. Explain that if Earth were as tiny as 1 Cheerio, the sun would be as big across its middle as the line of 109 Cheerios!
It is 93 million miles away from earth. How far away do your friends live? Most of them probably only live a few miles away from you!
It takes about 8½ minutes for light from the sun to get to us here on Earth.
Make a poster with your children of all the things they know about light. Label it "Things We Know about Light.'' They can decorate the poster with pictures of things they listed. Here are some questions to ask:
There is much more to learn about light than what you will find here. If you plan to continue studying light, make another list for "Things We Want to Know about Light.'' If you ask a question that your kids don't know the answer to (or if they ask you one that you can't answer!), add it to this poster. Then make a third list titled "Things We Have Learned about Light'' and use it to review what you have learned.
Demonstrate how light rays travel with this experiment for young children. Light will move in a straight line unless a material that it can't travel through blocks it. Then the light 'bends' and moves off in another direction.
What will happen when you shine a flashlight on different materials? Will light pass through or bounce off and go in a different direction? Have your children make a prediction about each material. Then, to test their predictions, hold each object, one at a time, a few feet in front of the wall. Shine the flashlight at the object (towards the wall). Observe what happens. Does any light reach the wall? Is it less light than without the object in front of the flashlight? Discuss how light can pass through some materials but not others. When light rays cannot pass through a material, they bend and go off in another direction. Can you see the light bending away from any of the materials that block it?