Electromagnetic Spectrum

Electromagnetic Spectrum

In today's lesson, you will learn about the different types of light waves. You will learn:

• what the electromagnetic spectrum is;

• how to measure and describe waves; and

• the types of waves on the electromagnetic spectrum.

Our glossary in our notebook defines light as "waves on the electromagnetic spectrum."

The electromagnetic spectrum is all types of light. Not just the types that we can see.

I have some fun facts about light in this lesson that we are going to check out!

Visible light is actually a tiny slice of the full spectrum.

It includes:

• Radio waves

• Microwaves

• Infrared

• Visible light

• Ultraviolet

• X-rays

• Gamma rays

​Fun Fact #1

Your body is glowing right now. Humans give off infrared radiation. Thermal cameras can see you in complete darkness

​Fun Fact #2

Microwaves and Wi-Fi Are Light

​Fun Fact #3

Gamma Rays Come From Space Explosions

​Fun Fact #4

Snakes Can See Heat

​Fun Fact #5

Sunburn Is From Invisible Light

​Sunlight is important for life on Earth. Plants use energy from sunlight for photosynthesis. The Sun's energy provides warmth for living things. All organisms rely on energy from the Sun, either directly or indirectly.


Think about how sunlight reaches Earth. In a previous lesson, you learned that heat from the Sun travels through space as radiation. Does light travel in a similar manner?

​The Electromagnetic Spectrum

The electromagnetic (EM) spectrum is the range of all of the types of light waves. You can see a very narrow range of light waves using your eyes. The remaining light waves are invisible to humans.

Examine the diagram of the EM spectrum. Seven types of EM waves are listed on the diagram. Note that only a very narrow section includes visible light, or the light that your eyes can see. That portion, called the visible spectrum, is enlarged above the diagram.

​EM waves move from one place to another using a process called radiation.

​Waves

All of the types of light, or EM radiation, travel in waves. A wave is a pattern of motion that transfers energy from one place to another. All EM waves carry energy. The amount of energy that a wave carries depends on its wavelength. A wave's wavelength is the distance from the peak of one wave to the peak of the next.

Why are we able to observe different colors?

​TED-Ed: Light Waves, Visible and Invisible

A wavelength is the length of one wave. There are three main ways to measure wavelength:

• from top to top;

• from bottom to bottom; and

• from midpoint to midpoint.

Multiple Choice

The shorter the wave length, the higher the energy.

• True

• False

Multiple Choice

Which type of EM wave has the longest wavelength?

• Radio Waves

• Gamma Rays

• Infrared Rays

​Electromagnetic Waves Video

Draw

Complete the four square. The bottom right space is there if you need more space for your examples.