Electromagnetic Waves & It’s Uses 8P3 8.P.3A.6 Obtain and communicate information about how various instruments are used to extend human senses by transmitting and detecting waves (such as radio, television, cell phones, and wireless computer networks) to exemplify how technological advancements and designs meet human needs.

Falcon Focus 1. What is the amplitude of the wave in diagram below? _________ 2. The wavelength of the wave in the above diagram? ___________  

Falcon Focus 3.All mechanical waves are classified as two types. What are they?   4. Which phenomenon is produced by two or more waves passing simultaneously?through the same region?

Falcon Focus 5. How many complete wave cycles are shown in the diagram below?

Essential Question What are two instruments that can enhance human sense through wave detection?

AGENDA 1. FALCON FOCUS 2. ESSENTIAL QUESTIONS 3. VIDEO 4. TAKE NOTES 5. COMPLETE THE WAVESTOWN ACTIVITY SHEET

OBJECTIVE: SWBAT: KNOW WHAT ARE ELECTROMAGNETIC WAVES LEARN THE USES OF ELECTROMAGNETIC WAVES IN TECHNOLOGY

Video On a sheet of paper, write the following: A E I O U

Researchers Today, you will become researchers. Whatever questions you may have about the lesson, we will research to fing the answer.

Electromagnetic Waves & Uses 8P3A.6

Electromagnetic Waves… Do not need matter to transfer energy. REMEMBER WHAT’S IN RED YOU WRITE!!!!

ELECTROMAGNETIC SPECTRUM… The electromagnetic spectrum depicts the range of all possible frequencies of electromagnetic radiation. Radio waves are classed as low frequency, long/high-wavelength and low energy waves, and gamma rays are classed as high- frequency, shorter/low-wavelength and high energy waves.

The whole range of EM wave… The ones humans can see are called visible light, a small part of the whole spectrum. Also remember that wavelengths or opposite from frequency.

As wavelength decreases, frequency increases…

What is the wavelength & frequency of an EM wave? Wavelength= distance from crest to crest. Frequency= number of wavelengths that pass a given point in 1 s. As frequency increases, wavelength becomes smaller.

ELECTROMAGNTIC SPECTRUM

CHECKPOINT WHAT IS THE ELECTROMAGNETIC SPECTRUM? HOW MANY ELECTROMAGNETIC WAVES ARE THERE? NAME THE ELECTROMAGNETIC WAVES IN ORDER FROM LOW TO HIGH FREQUENCY? DESCRIBE THE FOLLOWING FOR GAMMA RAYS: FREQUENCY, WAVELENGTH, & ENERGY DESCRIBE THE FOLLOWING FOR RADIO WAVES: FREQUENCY, WAVELENGTH, & ENERGY WHICH IS THE ONLY EM SEEN BY HUMANS? HOW WOULD YOU EXPLAIN THE RELATIONSHIP BETWEEN WAVELENGTHS AND FREQUENCY?

Uses of Electromagnetic Waves in Technology!!!! Signals that humans cannot sense directly can be detected through technological advances and designs. Radios, televisions, cell phones and wireless computer networks are examples of such technologies that are beneficial to humans by receiving and transmitting signals through radio waves.

These signals are transmitted through a medium (which can include the air or fiber optic cables) and captured by the device. The higher the frequency of the radio wave, the more information it can carry. For example, the radio waves transmitted and received by wireless computer networks are at much higher frequencies than those used by other devices.

Radios, televisions, and cell phones cannot detect these waves that carry the enormous amounts of information required for Internet usage. The signals sent and received by radios, televisions, cell phones and wireless networks are often digitized. When in digitized form, information can be recorded, stored for future recovery, and transmitted over long distances without substantial loss.

CHECK POINT 1. What are examples of such technologies that are beneficial to humans by receiving and transmitting signals through radio waves. 2. What are signals transmitted through? 3. The ___________the frequency of the radio wave, the __________ information it can carry. 4. The signals sent and received by radios, televisions, cell phones and wireless networks are often what? 5. When in digitized form, information can be what?

Radio Waves (communications---radio; tv; wireless computer) If you look at the diagram of the electromagnetic spectrum above, you will notice that radio waves have the longest wavelengths of the spectrum. Antennae of a radio detects radio waves.

Devices detect other frequencies: These waves must be turned into sound waves by a radio before you can hear them.

The speed of radio waves is approximately 185 miles per second, which is also the speed of light. Radio waves are detected using electrical circuits that receive these signals in an antenna, and then the radio frequencies are modulated (adjusted) through capacitors (a device used to store an electric charge), before emerging as sound in a speaker.

BENEFITS OF RADIO WAVES Radio waves are used to transmit signals through the air, with the main benefit being that the only equipment necessary is a transmitter and receiver. There are no cables to string or holes to dig as the waves are simply transmitted from one place to another.

Satellites communicate by using radio waves to send signals to the antennas on the Earth. The antennas then capture those signals and process the information coming from those signals.

DANGERS In large doses, radio waves, also known as radio frequencies, can disrupt biological functions and break down tissue.

Microwaves (cellphone service and microwaves for cooking) Microwaves are sometimes considered to be very short radio waves (higher frequency and higher-energy than radio waves).

Some important properties of microwaves are: 1. They are reflected by metal surfaces. 2. They pass through glass and plastics. 3. They pass through the atmosphere. 4. They are absorbed by water molecules.

BENEFITS Cell phones and satellites use microwaves between 1 cm & 20 cm for communication In microwave ovens, a vibrating electric field causes water molecules to rotate billions of times per second causing friction, creating TE which heats the food.

DANGERS Microwaves are absorbed by living tissue. Internal heating will damage or kill cells.

CHECKPOINT 1. Radio waves have the _____ wavelengths. 2. What detects radio waves of a radio? 3. Waves must be turned into what by a radio before you can hear them? 4. How are radio waves detected? 5. What is a capacitor? 6. Name 2 important properties of a microwave. 7. Name 3 things that uses microwaves. 8. How are microwaves dangerous?

Infrared Radiation (remote controls, toasters) Any object that radiates heat, radiates Infrared Radiation Infrared Radiation is absorbed by all materials and causes heating Used daily in remote controls, to read CD-ROMs It is used for night vision and security cameras because Infrared Radiation is visible in daytime or night-time 

DANGERS damage to cells (burns)

Ultraviolet Waves Danger: over-exposure to ultraviolet rays damages surface cells and eyes and can cause cancer. Have enough energy to enter skin cells Benefit: UV synthesizes vitamin D in skin.

X Rays X-rays detect bone breaks; they pass through flesh but not dense material like bones Dangers: X-rays damage cells and cause cancers.

Gamma Rays Gamma Rays cause and treat cancers Kill bacteria DANGERS In high doses, gamma can kill normal cells and cause cancers

CHECKPOINT 1. Infrared radiates what? 2. Infrared radiation is ____ by all materials. 3. Name 3 things infrared waves are used for. 4. Ultraviolet rays have enough energy to enter what? 5. Ultraviolet rays can cause what? 6. What do X-rays detect? 7. X-rays can pass through ___ but not through __. 8. Gamma rays ____ and ____ cancer. 9. What do ultraviolet rays, x-rays, and gamma rays have in common?

F Fill in the boxes with the waves of the EM spectrum.

Electromagnetic Waves Other information

Communications Satellites Thousands of satellites orbit Earth. A radio or TV station sends microwave signals to the satellite which amplifies the signal and sends it back to a different place on Earth. Satellites as well as radios (AM & FM) uses different frequencies to send & receive.

Global Positioning System GPS is a system of 24 satellites, ground monitoring stations and portable receivers that determine your exact location on Earth. GPS receiver measures the time it takes for radio waves to travel from 4 different satellites to the receiver. The system is owned and operated by the US Dept of Defense, but the microwaves can be used by anyone.

Wavestown Instruction Color and Label the electromagnetic Spectrum on the Wavestown Spectrum. Color Wavestown to match your electromagnetic spectrum. Use the Information in your notes to complete this assignment