Light Properties and the Speed of Light

How does the sun's light make it all the way here to Earth?

The sun's light travels. It moves from point A, the sun, to point B, the Earth.

Light Travels

• Light travels in straight lines.

• It moves out of its source and travels along until it hits something else.

• A ray is the straight path light travels. 

• A bunch of rays grouped together is called a beam.

  (Ex: laser beam)

Multiple Choice

Light travels in ________.

• straight lines

• circles

• dots

Light Travels

Light can move through a few materials easily. Other materials are more resistant to light passing through.

Air, water, and glass are examples of different materials that light can travel through. Different materials or media have different properties, which means they interact with light differently. In most cases, when light moves from one material to another, the light changes direction.

When light strikes...

When light strikes an object or surface, one of three things will happen to it. What happens to it depends on whether the object it strikes is transparent, translucent, or opaque. 

When light strikes...

• Transparent: light will all pass through.

• Translucent: some of the light will pass through

• Opaque: none of the light will pass through

Multiple Choice

What is translucent matter?

• matter that allows light to pass easily

• matter that doesn't allow light to pass through easily

• matter than lets no light through

• matter that doesn't exist

Multiple Choice

What is opaque matter?

• matter that allows light to pass easily

• matter that doesn't allow light to pass through easily

• matter than lets no light through

• matter that doesn't exist

Multiple Choice

This is an example of ........

• transparent

• translucent

• opaque

Multiple Choice

This is an example of ......

• transparent

• translucent

• opaque

Multiple Choice

This is an example of ........

• transparent

• translucent

• opaque

Multiple Choice

How do opaque objects get their color?

• reflecting only the light that shows their color

• absorbing all light

• reflecting all light

• only reflecting colors that are not it's color.

​It sounds weird but it's true!

​Light "particles" are called photons.

Multiple Choice

What is transparent matter?

• matter that allows light to pass easily

• matter that doesn't allow light to pass through easily

• matter than lets no light through

• matter that doesn't exist

Open Ended

Why do you think the sky is blue?

​1m = 1000mm
1 mm = 1,000 micrometers
1 micrometer = 1,000 nanometers
1 m = 1,000,000,000 nanometers

The wavelengths of light are measured in nanometer. These are extremely small units!