<< Back to Lessons Index

Science_Lab_Yellow / Lesson 1: Seeing Without Light

Seeing Without Light

What will we be learning today?

  • In this lesson, we are going to learn all about can you see without light.

  • Can You See Without Light?

    The Moon looks very bright in the evening sky. However, the Moon does not give off any light of its own.


     We are able to see the Moon only because sunlight bounces off the Moon's surface and into our eyes. The dark half of the Moon in the photo is actually a part of the side of the Moon that is not being lit by the Sun. Since sunlight does not reach the Moon there, we cannot see this part of the Moon's surface.


    You see the Moon because it is lit by the Sun.


    What is light? Scientists know that light, like sound, is not matter. We could never observe a "piece" of light at rest, taking up space and having mass. Light and sound are both means of transferring energy between points.


    The photograph below clearly shows that light carries energy. In fact, light is a form of energy.



    A beam of light from a laser carries enough energy to melt the hardest metals.


     How Light Is Produced

    All the objects we can see either give off their own light or, more often, reflect the light from a source such as a light bulb or the Sun. The photos show objects that produce light. As you can see, heat is involved in all three cases. Nuclear reactions heat the Sun. Chemical reactions heat the burner flame. Electricity heats the glowing wire of the light bulb.





           


    In a very hot material, the molecules move swiftly. At times when these molecules collide, some energy from the collision may be given off as light. At other times the molecules themselves vibrate and give off light waves.


    Any light source converts energy of one kind into light energy. For example, the Sun makes light from nuclear energy, a burner makes light from chemical energy, and an electric light bulb makes light from electrical energy. The light waves given off by these sources carry the energy away at great speed.


     Let's Review What We Learned Today!

  • Now complete your worksheet!