Learning objective: Explain that objects can be seen only when light shines on them or when they make their own light, and identify sources of light.
Light is what lets us see the things around us. Without light, everything looks completely dark, even if the object is right in front of you.
Look at the picture above. In the dark room on the left, you cannot see the toy at all — it's too dark! In the room on the right, light shines in, and now you can see the toy clearly.
A light source is something that makes its own light. The sun is the biggest light source we have — it lights up the whole daytime sky. Other light sources include lamps, flashlights, and candles.
The moon looks bright at night, but the moon does not make its own light! It only looks bright because sunlight bounces off it. A mirror is the same way — it doesn't make light, it just bounces light that's already there.
Understanding light helps you understand why it's dark at night (no sunlight) and why turning on a lamp helps you see in a dark room. You'll learn more about how light interacts with objects in the next lesson.
In a dark room, you cannot see anything. When light shines in, you can see the toy clearly.
What do you need to see an object?
Which of these is a light source?
Why does the moon look bright at night if it isn't a light source?
Walk around your home or classroom and find 3 light sources. Draw or list them.