The Electromagnetic Spectrum DCMS Science 2016

Electromagnetic Waves An electromagnetic wave consists of vibrating electric and magnetic fields that move through space at the speed of light.

Electromagnetic Waves Light and all other electromagnetic waves are produced by charged particles. Each of these has an electric field around it. This has the ability to push or pull on other charged particles.

Electromagnetic Waves In an electromagnetic wave, electric and magnetic fields vibrate at right angles to each other and constantly cause each other to change.

Electromagnetic Waves The energy that is transferred through space by electromagnetic waves is called electromagnetic radiation. They can transfer energy through empty space. This is why we can see the sun and stars.

Electromagnetic Waves The speed of light is about 300,000 kilometers per second. This is the speed of electromagnetic waves in a vacuum. Light from the sun reaches earth how fast? 8 minutes. Air does slow down these waves, but they are still much faster than sound waves.

Electromagnetic Waves Look at figure 2. Explain how polarizing filters work.

Electromagnetic Waves The movement of electrons causes an electric current to flow. Light can cause electrons to be actually knocked out of a substance… this is called the photoelectric effect. Each packet of light energy is called a photon.

Electromagnetic Waves

Electromagnetic Waves All electromagnetic waves travel at the same speed in a vacuum, but they have different wavelengths and frequencies.

Electromagnetic Waves Write the formula that shows how speed, wavelength, and frequency are related. S = W x F

Electromagnetic Waves As the wavelength decreases the frequency increases.

Electromagnetic Waves Waves with the longest wavelengths have the lowest frequencies, and waves with the shortest wavelengths have the highest frequencies. The amount of energy carried by an electromagnetic wave increases with frequency.

Electromagnetic Waves What are the 7 types of electromagnetic waves in the spectrum?

Electromagnetic Waves Radio waves have the longest wavelengths and the lowest frequency.

Wave Uses Broadcast Waves

Wave Uses Microwaves

Wave Uses Radar

Wave Uses Infrared Rays

Wave Uses Electromagnetic waves that you can see are called visible light. These appear white but are actually a mixture of colors. They can be separated by a prism into the following colors:

Wave Uses Small doses cause skin cells to produce Vitamin D. Too much causes your skin to burn, as well as skin cancer and eye damage. How can you block UV rays?

Wave Uses Just shorter wavelengths than visible light are ultraviolet rays. They have higher frequencies, so they carry more energy. In fact, they can damage or kill living cells. How is this used in the hospital?

Wave Uses X rays have a higher frequency than UV rays do. Therefore they carry more energy. They can penetrate most matter, but not bone or lead. How do we use this to our advantage?

Wave Uses What waves have the highest frequency? Gamma rays. They also have the shortest wavelengths and the greatest amount of energy.

Wave Uses Give three uses of gamma rays: Diagnose cancer & Other abnormalities Gamma ray telescope Kill cancer cells

Wave Uses Explain how radio and television use waves, including AM and FM.

Wave Uses Explain how cellular phones use waves.

Wave Uses Communications satellites receive radio, TV, and telephone signals and relay those signals back to receivers on Earth.

Wave Uses Explain how GPS works.

Question 1 Ella is learning about different types of electromagnetic radiation. She makes the following list about one frequency of radiation: Can damage cells of living things Blocked by Earth’s ozone layer Which type of radiation does Ella’s list describe? A. Infrared B. Microwave C. Ultraviolet D. Visible

Question 2 A sewer system operator would like to use electromagnetic radiation to destroy bacteria and other organisms in filtered wastewater before it is released into the environment. Which type of electromagnetic radiation is capable of treating the wastewater? A. Ultraviolet B. Infrared C. Visible D. Radio

Question 3 Darnel wants to list types of radiation based on their ability to penetrate human skin. Which list shows the order of radiation types from lowest to highest penetration? A. Infrared radiation, microwaves, radio waves, visible light, x-rays, gamma rays, UV rays B. X-rays, gamma rays, infrared radiation, microwaves, radio waves, UV rays, visible light C. Visible light, infrared radiatio, UV rays, microwaves, radio waves, x-rays, gamma rays D. Radio waves, microwaves, infrared radiation, visible light, UV rays, x-rays, gamma rays