Seeing in the Dark Reflections of Light

Things to Learn Some things make their own light. They are called light sources. Most things we see cannot make their own light. We see them because they reflect light. Misconceptions: People eyes adjust to the dark so they can see a little bit in total darkness.

We can see things that do not make their own light because light is reflected off of them.

At night there is usually enough light from the moon, street lights, or homes that we can see some things like a toy tractor. We cannot always tell the color, when the light source is weak. Colors are hard to detect in weak light. This causes problems in identifying car color in night time crimes.

At night when there is no moon we can still see some things from reflected star light, but things are very hard to see. It is difficult to walk on a bumpy forest path on a moonless night.

With no light source, you can see nothing at all, not even your hand when it is touching your nose. Notice that the tractor is still in the picture and so is the eye, but the tractor cannot be seen because there is no light.

Some people say that their eyes become adjusted to the dark Some people say that their eyes become adjusted to the dark. Their eyes become adjusted to low levels of light.

No one can see anything without some light source Notice that the tractor is still in the picture and so is the eye, but the tractor cannot be seen because there is no light.

Draw the light source and an eye. Draw something simple that you see in the room like a pencil or a book. Draw the light source and an eye. Draw arrows to show the pathway of light. Label the Light Source, Light from the Source, Reflected Light, and Eye. Angles of reflection are not important at this point. Be sure students understand the pathway of light.

Did You Learn? Some things make their own light. They are called light sources. Most things we see cannot make their own light. We see them because they reflect light. Some people say they can see in total darkness, but they cannot.

Even More Reflections Light can be reflected off of many surfaces and back to our eyes. Light is bouncing all around. Students should not come away with the misconception that light comes straight from the light source to the object to our eyes.

With a flashlight you can see ahead, but not much to the side of the beam.

When a flashlight shines directly on an object, lots of light is reflected so we can see it. It is still dark in the areas where the light does not shine.