Light and color

Light and color

What is light and how do we see color?

Multiple Choice

Light is a kind of.....

• reflection
• energy
• heat
• matter

The electromagnetic spectrum

• We usually think of "light" as the light we can see, visible light.

• Scientists also include the rest of the electromagnetic spectrum when they talk about light

• Visible light can be split up into different colors

https://image.shutterstock.com/image-illustration/visible-light-wave-length-difference-260nw-514067863.jpg

Multiple Choice

What do most people usually mean when they say "light"

• The light that we can see

• Gamma rays

• Infrared

• A form of energy

Multiple Choice

What do scientists mean when they say "light"

• Visible light

• Gamma rays

• Infrared

• The electromagnetic spectrum

Multiple Choice

What kind of light propagates (moves well) in water?

• Ultraviolet

• Gamma

• Infrared

• Visible light

When light hits an object it can be:

• Reflected

• Absorbed

• Transmitted (go through)

Reflected light

• We see objects ONLY when light reflects off of them and reaches our eyes

• The color of an object depends on what color of light it reflects

• For example RED objects reflect only red light.

Multiple Choice

What color light does a traffic cone reflect?

• Orange

• Blue

• Green

• Purple

Absorb

• Light that an object doesn't reflect is absorbed

• Absorbed light gets turned into heat

• This is why darker colored objects heat up more in the sun

Multiple Choice

If you want to warm up on a cold day what color should you wear?

• White

• Grey

• Yellow

• Black

Multiple Choice

If you want to help a house stay cool in a hot climate what color would you make the roof?

• White

• Grey

• Black

• Purple

Humans have 2 kinds of receptors in their eys

• Rods sense the amount of light

• Cones sense color

• There are 3 kinds of cones: Red, Green and Blue

Multiple Choice

What do the CONES in your eyes sense?

• Amount of light

• Colors

Multiple Choice

What do the RODS in your eyes sense?

• Amount of light

• Colors

Multiple Select

What are the 3 colors our cone receptors sense?

• Red

• Yellow

• Green

• Blue

Deep Look | The Snail-Smashing Mantis Shrimp | Season 3 | Episode 20 | PBS

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Additive colors

• Technology that projects light uses additive color mixing

• Our eyes sense color through additive mixing

• TV's, computer screens, projectors

• ADDING ALL THE COLORS MAKES WHITE

Multiple Select

What colors do tv screens use to make all the colors (choose 3)

• Red

• Yellow

• Green

• Blue

Multiple Choice

In additive color mixing: Red and green make:

• Brown

• Yellow

• Green

• Purple

Multiple Choice

In additive color mixing: Red and Blue make:

• Brown

• Yellow

• Green

• Purple

Multiple Choice

How do tv screens make white or how do your eyes sense white?

• No colors of light

• Equal amounts of all colors

• Only a small amount of all colors

Subtractive color mixing

• This is the color mixing used in printing or in painting

• Red, Yellow, Blue are the primary colors you recognized from painting

• Cyan, Magenta and Yellow are used in printing (with black)

In subtractive color mixing you get white by NOT adding any colored ink or paint.

Mixing paints and inks

• Red+Blue = Purple

• Red + Yellow = Orange

• Yellow + Blue = Green

• All three = black

• None = white

Multiple Select

What colors would you mix to get orange?

• Red

• Yellow

• Blue

Multiple Select

What colors would you mix to get Green?

• Red

• Yellow

• Blue

Multiple Select

What colors would you mix to get Purple?

• Red

• Yellow

• Blue

Multiple Select

Last question: What colors would you mix to get Black?

• Red

• Yellow

• Blue

It's Okay to Be Smart | Why Is Blue So Rare In Nature? | Season 5 | Episode 11 | PBS

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