Science of Light

Science of Light

What is light made of?

This is not an easy question. Light has no mass and is not really considered matter. So does it even exist? Of course it does! We couldn't live without light. Today scientists say light is a form of energy made of photons. Light is unique in that it behaves like both a particle and a wave.

Multiple Choice

light is:

• a form of energy

• a form of capacity

Why does light go through some things and not others?

Depending on the type of matter it comes into contact with, light will behave differently. Sometimes light will pass directly through the matter, like with air or water. This type of matter is called transparent. Other objects completely reflect light, like an animal or a book. These objects are called opaque. A third type of object does some of both and tends to scatter the light. These objects are called translucent objects.

Multiple Choice

light passes directly through

• solid objects

• light and water

Light helps us to survive

Without sunlight our world would be a dead dark place. Sunlight does more than just help us see (which is pretty great, too). Sunlight keeps the Earth warm, so it's not just a frozen ball in outer space. It also is a major component in photosynthesis which is how most of the plant life on Earth grows and gets nutrients. Sunlight is a source of energy as well as a source of vitamin D for humans.

Multiple Choice

Sunlight is a source of energy as well as a source of:

• vitamin C

• vitamin D

The speed of light

Light moves at the fastest known speed in the universe. Nothing moves faster than (or even close to) the speed of light. In a vacuum, where there is nothing to slow it down, light travels 186,282 miles per second! Wow, that's fast! When light travels through matter, like air or water, it slows down some, but it's still pretty fast. To give you an idea as to how fast light is, we'll give you some examples. The Sun is almost 93 million miles from the Earth. It takes around 8 minutes for light to get from the Sun to the Earth. It takes around 1.3 seconds for light to go from the moon to the Earth.

Multiple Choice

light travels 186,282

• miles per minute

• miles per second

that's all for now