How Light Travels

How Light Travels

Learning Objectives

Students will develop and use models to describe light's path as straight lines and describe how objects functions to interact with light waves through reflection, absorption, and transmission.

Poll

Sound and light both travel by waves. In order to hear sounds or see light, waves must travel from one place to another and enter either ears or eyes. How do you think these waves travel?

• They both need to travel through matter [ Solid, liquid and gas ]

• Neither needs to travel through matter [ Solid, liquid and gas ]

• Only one of them needs to travel through matter [ Solid, liquid and gas ]

What is light?

Electromagnetic waves radiate electric and magnetic fields which can be detected by human eyes.

Multiple Choice

Light is:

• matter

• energy

• wave

Electromagnetic Spectrum

The electromagnetic spectrum is the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies.

Multiple Choice

Which has the longest wavelength?

• Radio waves

• Visible light

• X-rays

Open your Google classroom

Work on WS-Across the Spectrum

Transparent

Transparent is a material that allows almost all of the light striking it to pass through, through which objects can be seen clearly.

In this example, the glass is Transparent material.

Translucent

Translucent is a material that allows most of the light striking it to pass through, but through which objects appear blurry.

In this example, the glass is Translucent material

Opaque

Opaque is a material that absorbs most of the light that strikes it. Therefore, you can't see objects through it.

In this example, the glass is Opaque material

Multiple Choice

In the following example, which one is an example of Transparent glass?

• A

• B

• C

Multiple Choice

In the following example, which one is an example of Translucent glass?

• A

• B

• C

Open Ended

What are the things you can see in the room?

Open Ended

Why might you see some things in the room but not other things?

Electromagnetic Radiation

Electromagnetic Radiation doesn't need a medium to travel through.

Watch this video to learn more:

https://www.youtube.com/watch?v=LTvHlYz61lY

Multiple Choice

Sound and light both travel by waves. In order to hear sounds or see light, waves must travel from one place to another and enter either ears or eyes. How do you think these waves travel?

• They both need to travel through matter [ Solid, liquid and gas ]

• Neither needs to travel through matter [ Solid, liquid and gas ]

• Only one of them needs to travel through matter [ Solid, liquid and gas ]