How People Learned About Light and Dark
Long, long ago, people noticed that they could see things during the day but not at night. They wondered why! Cave people made the first fires to help them see in dark caves. The fire made light, and light helped them see!
All these people were trying to solve the same problem: How can we see things when it's dark? They discovered that we need light to see!
The Big Ideas About Light and Seeing
There are some very important things to know about how we see. These big ideas will help you understand why you can see some things and not others!
We Need Light to See
Light Comes from Sources
Light Bounces Off Objects
Some Things Block Light
How We See Things
Look at the picture above! First, light comes from the sun. Then the light hits a red book. The book doesn't keep all the light - it bounces some light back. That bounced light goes to your eye, and that's how you see the book is red!
Things That Make Light
Some things make their own light! We call these light sources. Light sources are very special because they help us see everything else!
The sun is the biggest light source we know! It gives us light all day long. When the sun goes down, we use other light sources like light bulbs and flashlights to help us see in the dark.
When Light Gets Blocked
Sometimes things get in the way of light! When something blocks light, it makes a shadow. Shadows are dark places where light cannot go.
Look at the picture! The tree is blocking some of the light rays from the sun. Where the light can't go, there is a dark shadow. You can make shadows too! Hold your hand up to a light and watch your hand's shadow appear on the wall.
Let's Figure Out When We Can See!
Let's work together to figure out when Tommy can see his toy car! We'll use what we learned about light and seeing.
So Tommy can see his toy car when there is light from the sun or a light bulb. But he cannot see it when it's dark and there is no light source!
Bright Places and Dark Places
Some places are very bright and some places are very dark. Let's compare them and see what makes the difference!
| Bright Places | Dark Places |
|---|---|
| Outside on a sunny day | A closet with the door closed |
| A room with lights on | Outside at night with no streetlights |
| Near a campfire | Under your bed |
| You can see everything clearly | You can't see much at all |
Cool Things About Light You'll Learn Later
There are even more amazing things about light that you'll learn when you get older! Here's a peek at what's coming.
| What You Know Now | What You'll Learn Later |
|---|---|
| Light helps us see things | Light is made of tiny particles called photons! |
| Light bounces off objects | Light can bend when it goes through water or glass |
| Some things make light | Light travels super fast - faster than anything else! |
For now, just remember that light is what helps us see! When you get to second grade and beyond, you'll discover even more cool secrets about how light works.
Let's Practice What We Learned!
What We Learned About Light and Seeing
We learned that light is what helps us see everything around us! Light sources like the sun, light bulbs, and flashlights make their own light. This light bounces off objects and comes back to our eyes, which is how we see things! When something blocks light, it creates a shadow - a dark place where we can't see as well.
The most important thing to remember is that we need light to see! In bright places with lots of light, we can see everything clearly. In dark places with no light, we can't see much at all. Now you know why you need to turn on a light when it gets dark!