WHAT IS LIGHT?

All light has a source, or something it comes from. And that source can be natural or artificial. Sources of natural light are the sun, other stars, lightning and fire. Some living things can even make their own light, like fireflies and jellyfish. Sources of artificial light are light bulbs, computer or TV screens and neon lights, to name a few.

The sun is our main source of light. All living things need energy from the sun to survive. Plants use sunlight to make their own food. Most animals need sunlight to warm their bodies. Sunlight even makes water move through the water cycle.

Which of the following is not true about sunlight?

• a. It moves water in the water cycle

• b. It makes computer and TV screens bright

• c. it helps plants make their own food.

• d. it keeps many animals warm.

Tags

NGSS.MS-ESS2-4

NGSS.MS-LS1-6

NGSS.MS-LS2-3

Light moves. It travels all the way from the sun or from other stars to the Earth. It travels from any source. That's why we can see it, because it travels into our eyes. Light travels in a straight line, and it travels very fast.

When light hits an object, some of the light reflects or bounces off. That's why we can see it. Mirrors reflect almost all the light that hits them.

Light moves and travels ____.

• a. by reflecting off of our eyes.

• b. in a slow zigzag by bouncing off stars.

• c. quickly, in a straight line

• d. from only one source—the sun.

Tags

NGSS.MS-PS4-2

Light can also pass through some things. Light can easily pass through clear objects, like glass windows. That's why you can see through clear objects.

There are also some objects that let only some light pass through—stained glass windows and sunglasses, for example. They block some light and let other light pass through. So you can see through them, but not as well as you can see through clear glass.

Which of the following is an example of an object that would let only some light through?

• a. a full length mirror

• b. a clear raincoat

• c. a regular glass window

• d. a green plastic water bottle

Tags

NGSS.MS-PS4-2

Sometimes light hits an object, and it can't pass through it. The object blocks the light and keeps it from going to the other side. You can't see through objects like books, a refrigerator or a tennis shoe. If you made a sneaker out of glass, you could see through it, but it wouldn't be very comfortable.

We see shadows, or darker areas, when objects block the light. Have you ever made a shadow puppet on the wall? You can do that when there is one bright light aimed at a wall and you put your hand in front of it. The shadow is the shape of the thing that blocks the light.

Shadows are the shape of the thing that blocks the light.

When you make a shadow puppet ____.

• a. your hand creates the shadow by blocking part of the light.

• b. the light reflects off of your hand to create the shadow.

• c. all the light surrounding your hand is made brighter.

• d. the light passes through your hand to form the shadow.

Tags

NGSS.4-PS4-2

Most objects also absorb or take in some of the light. Instead of bouncing back, this light gets absorbed. Shiny objects (like glass or metal) reflect more light than dull objects (like carpet or a sandwich). So a rug absorbs more light and isn't shiny. A necklace absorbs less light, and so the light bounces off and it looks shiny.

A glass bottle will _______.

• a. reflect all the light that hits it.

• b. absorb exactly the same amount of light as a wool sweater.

• c. absorb all the light that hits it.

• d. reflect more light than a wool sweater.

Tags

NGSS.MS-PS4-2

All objects—dull or shiny—reflect light. Shiny objects just reflect light the best. In order to see something, a source of light must shine on the object, then that light reflects off the object into your eyes. Without this reflection, you would not see. That's why when it's "pitch black," you can't see anything—there's no light to reflect off any objects. Though shiny objects reflect light best, anything you can see is reflecting light.

What is the best evidence that you are experiencing “pitch blackness”?

• a. you can see shadows

• b. the moon is visible in your window

• c. you can’t see any objects

• d. the objects in the light are dull

Of course, there's rarely a time when there isn't any light. Even at night, when it's dark out, the stars, moon, street lights and lights inside your home illuminate the world. But it is mostly dark at night. Why is that? At night, the part of the Earth where you live turns away from the sun, so you can't see it. But on the opposite side of the planet, it's daytime!

Which of the following best describes the relationship between the Earth and the sun?

• a. The Earth gets no light from the sun, and is illuminated by the moon.

• b. When it’s night time, your part of the Earth is facing away from the sun.

• c. The same part of the Earth faces the sun at all times.

• d. The Earth gets an equal amount of light from the sun and moon.

Tags

NGSS.MS-ESS1-1

Which statements depicts the characteristics of light?

• a. light travels in a straight path

• b. light travels fast

• c. both a and b

• d. neither a or b

The diagram is an example of light _____.

• a. being absorbed into material

• b. traveling through material

• c. reflecting off material

• d. blocking material

Tags

NGSS.MS-PS4-2

A shadow will form when an object is _____

• a. between light and a surface.

• b. between dark and a surface

• c. reflecting the light

• d. absorbing all the light

Tags

NGSS.4-PS4-2