Unit 2: Waves. Electromagnetic Spectrum.

Electromagnetic Spectrum: The entire range of electromagnetic waves.

https://education-portal.com/academy/lesson/the-7-major-regions-of-the-electromagnetic-spectrum.html#lesson

Image: Klaus Schmitt

The petals on the flower look solid yellow to you but a bee may see dark ultraviolet markings that make the same flower appear quite different

to the bee.

Fun Fact

Unit 2: Waves. Electromagnetic Spectrum.

All EM waves travel at the same speed: 300 000 000 m/s

The waves are arranged from longest to shortest wavelength

**As wavelength decreases the frequency increases**

Unit 2: Waves. Electromagnetic Spectrum.

Radio waves have some of the

longest wavelengths and lowest

frequencies. They are the lowest energy waves. This makes them the safest.

TV signals are carried by radio waves too.

Unit 2: Waves. Electromagnetic Spectrum.

Microwaves: have shorter wavelengths and higher frequencies than radio waves.

Microwaves are used in radar and in monitoring the movement of ships and airplanes.

Unit 2: Waves. Electromagnetic Spectrum.

Infrared Waves These waves heat the Earth’s surface.

Warmer objects give off more infrared radiation

than cooler objects

Unit 2: Waves. Electromagnetic Spectrum.

Unit 2: Waves. Electromagnetic Spectrum.

Let’s stop and think…

How do infrared waves differ from radio waves in terms of frequency and wavelength?

Visible Light: the narrow range of wavelengths and frequencies in the EM spectrum that

humans can see.

Unit 2: Waves. Electromagnetic Spectrum.

Red light: Longest wavelengths Violet light : Shortest wavelengths (higher energy)

Ultraviolet Light

Unit 2: Waves. Electromagnetic Spectrum.

Positive Effects of UV light •Artificially produced to kill

bacteria on food and surgical instruments

•Limited exposure to UV in the sun produces vitamin D

Negative Effects of UV light •Sunburn

•Skin cancer •Damage to the eyes

•Wrinkles •Premature aging of the skin

X Rays: Carry a great deal of energy, allowing them to penetrate a variety of

materials. Too much exposure can

damage or kill living cells.

Unit 2: Waves. Electromagnetic Spectrum.

Gamma Rays: Have the most energy (+) Used to treat some forms of cancer. (-) Produced during nuclear reactions.

Unit 2: Waves. Electromagnetic Spectrum.

Ticket Out the Door…

1. How are wavelength and frequency related?

2. How is the electromagnetic spectrum arranged?

3. Which type of light has the longest

wavelength in the electromagnetic spectrum?

Unit 2: Waves.