RO Science 10 Q2 LP3

Science - Grade 10 ELECTROMAGNETIC WAVES I. INTRODUCTORY CONCEPT Filipinos are fond of using cellphones for gaming, texting and calling, watching our favorite movies and teleseryes, live performances, and concerts of both local and foreign artists. We also love to listen to music and songs of our idolized singers and performers. Have you ever wondered why the performances of these artists can be watched on our television even though they are very far? How the messages of your friends and families reached you through cellphones? The Philippines is now facing this very alarming pandemic known as COVID- 19. One of the ways on how to detect the symptoms of this disease is through the use of thermal scanners that uses infrared radiation. In hospitals gamma rays and x- rays are used to diagnose and treat diseases. These three types of EM waves can be useful or harmful depending on its use. II. LEARNING COMPETENCIES MELC: Cite examples of practical applications of the different regions of EM Waves, such as the use of radio waves in telecommunications. (S10FE-IIc-d-48) Objectives: 1. Define or describe the different types of Electromagnetic (EM) waves. 2. Compare the frequencies and wavelength of the different Electromagnetic (EM) waves. 3. Cite useful applications of different Electromagnetic (EM) waves. III. ACTIVITIES ELICIT: Let’s check your prior knowledge about our lesson for today. Answer the questions below. Directions: Identify what is being asked or described in each item then write the letter of the correct answer in your answer sheet. 1. What is the best application of very high frequency radio waves? A. AM radio broadcasting B. FM radio broadcasting C. Satellite communication D. TV broadcasting and satellite communication RO_Science_Grade10_Q2_LP3 1

2. What is not a characteristic of radio waves? A. shorter Range C. not light sensitive B. not line of sight D. can pass through walls 3. What is the disadvantage of radio waves? A. More costly than infrared B. It is easier to “eavesdrop” since signals are transmitted in space rather than a wire. C. Low power requirements that make it ideal for laptops, and other technological devices. D. Communication devices that make use of the same frequencies interfere with their transmission. 4. How does a microwave oven cook food inside it? A. Food releases microwave frequencies that cook the food. B. Heat is released outside the microwave oven which cooks the food. C. Molecular friction is eliminated thus, cooking the food in a microwave oven. D. Food absorbs certain microwave frequencies which penetrate the food being heated and produces heat that will cook the food. 5. What is not a useful application of microwave? A. RADAR. B. TV transmission C. Used in navigation. D. Satellite communications. 6. What is not an application of infrared radiation? A. Infrared telescopes are used for seeing the dark. B. Infrared radiation is used in the production of Vitamin D in our skin. C. Infrared scanners are used to show the temperature variation of the body. D. Infrared photographs taken from a satellite with special films provide useful details of the vegetation of the Earth’s surface. 7. What is the best useful application of visible light? A. Visible light helps in making rainbows. B. Visible light augments communication devices. C. Visible light helps in the production of computers. D. Visible light enables us to see the beauty of our surrounding. 8. What type of EM waves is used in sterilizing water from drinking fountains? A. Gamma ray B. Microwave C. UV radiation D. X-ray RO_Science_Grade10_Q2_LP3 2

9. Where is ultraviolet ray used? A. It is used to kill cancer cells. B. It is used in the production of vitamin D in our skin C. It is used in identifying original from fake banknotes. D. It is used in sterilization of water in drinking fountains 10. How are x-rays produced? A. X-rays are produced when fast moving protons hit a metal target. B. X-rays are produced when fast moving electrons hit a metal target. C. X-rays are produced when fast moving protons hit a non-metal target. D. X-rays are produced when fast moving electrons hit a non-metal target. ENGAGE: Are you familiar with the different Electromagnetic (EM) waves? Let’s do the activity. Activity 1: COMPLETE ME! Complete the statement below to describe the terms: 1. Microwaves have smaller _______ than _______ waves. They are used in ________ communications, _______, television transmission and _____. radio cooking satellite radar wavelengths frequency 2. A radar system is consists of an ________, ________, and a _____. transmitter antenna receiver satellite 3. A cell phone is a _____ transmitter and ______ that uses ________. radio receiver microwaves frequency 4. Communication ________ travel around the _______ at an altitude of __________ above the equator. They move at a speed of ______ and revolve around the earth every ___. 11 300 km/h earth satellites 35, 000 km 24 hours 365 days 5. Antennae are _____ to point in ____ directions towards these _____. fixed satellites mounted receiver 6. Ultra violet ______ lies just beyond the ____ end of ________ visible spectrum radiation violet red 7. Gamma rays are used to treat _______ through the process called _____. cancer radiotherapy diseases 8. Infrared radiation lies _______ the ______ end of ________. red beyond visible spectrum violet 9. Radio _______ have longest ______ in the _________. electromagnetic spectrum waves wavelength signal RO_Science_Grade10_Q2_LP3 3

10. All x-rays are _____ because they can _____ healthy living ____ of our body. cells damage dangerous helpful Activity 2. MATCH ME! On the next page, are different pictures showing how Electromagnetic (EM) waves are applied. Match it to the EM waves in the table below by writing the letter only. EM Wave Applications/Uses Radio waves Microwaves Infrared Visible light Ultraviolet X-rays Gamma rays A B C http://news-medical.net http://independentimaging.com http://universetoday.com D E F http://symmetrymagazine.org http://digikey.com http://elprocus.com G www.darvill.clara.net RO_Science_Grade10_Q2_LP3 4

Activity 2. EM WAVES PUZZLE Direction: Complete the crossword puzzle below. 1 2 8 4 5 3 7 6 9 10 ACROSS: DOWN: 4. lie at the other end of the 1. unit used to measure the frequency of electromagnetic spectrum waves 7. lies just beyond the violet end 2. formulated the electromagnetic wave of the visible spectrum theory 9. has the longest wavelength in 3. is a disturbance that transfer energy the EM spectrum 5. radio transmitter and 10. the only EM wave that can be receiver that uses seen by humans microwaves 6. consists of an antenna, transmitter and receiver 8. penetrate the food being heated EXPLAIN: TYPES OF ELECTROMAGNETIC (EM) WAVES RADIO WAVES Radio waves have the longest wavelength in the electromagnetic spectrum. They are produced by making electrons vibrate in an antenna. They are used to transmit sound and picture information over long distances. https://ya-webdesign.com/image/radio-clipart/189142.html RO_Science_Grade10_Q2_LP3 6

Radio waves have a very wide range of wavelengths. The whole region of the radio wave is divided into smaller regions or wavebands. Each waveband is allocated by law to a specific radio service. Low frequency waves are suitable for communication over great distances. But the curvature of the earth limits the range to about 80 kilometers. To extend the range, a repeater is used. The repeater receives signal and re-transmits it to the receiving station. High frequency waves can be reflected by the ionosphere. This enables the waves to be transmitted over great distances. Radio waves have the following characteristics: 1. Not line of sight 2. Can pass through walls 3. Longer range 4. Not light sensitive Some disadvantages of radio frequencies include: 1. Communication devices that make use of the same frequencies interfere with their transmission. 2. It is easier to “eavesdrop” since signals are transmitted in space rather than a wire. 3. More costly than infrared MICROWAVES Microwaves have smaller wavelengths than radio waves. They can penetrate the atmosphere of the earth. This is the reason why they are used in satellite communications. Communication satellites travel around the earth at an altitude of 35, 000 km above the equator. They move at a speed of 11, 300 km/h and revolve around the earth every 24 hours, the same rate as the rotation of the https://www.pinclipart.com/pindetail/iho mhw_clipart-science-microwaves-use-a- earth. microwave-png-download/ Microwaves signals are transmitted by an antenna to a satellite which amplifies and re-transmits the signal to an antenna in other parts of the world. Microwaves are applied in so many ways from texting to cooking, and to communications to the rest of the world. RO_Science_Grade10_Q2_LP3 7

Applications of Microwaves 1. Satellite communication 2. Radars 3. TV transmission 4. Microwave oven How a microwave oven cooks food inside it? 1. A part of the oven produces microwaves. 2. The microwaves are sent to the reflecting fan. 3. The microwaves are reflected in many directions by the fan and the walls of the microwave oven. 4. As microwaves pass through the food, they transfer energy to the water molecules in the form of heat. This will cook the food. INFRARED RADIATION Infrared radiation lies beyond the red end of the visible light. It is emitted by all objects. The amount and wavelength of radiation depend on temperature. Below 5000 C, an object emits only infrared radiation. Above 5000C, an object glows and emits both infrared and some visible light. Our bodies radiate infrared and under infrared camera or a night vision goggle, our images appear in variety of colors. The differences in color determine the differences in temperature. Infrared zoo gallery dog retrieved from http://coolcosmos.ipac.caltech.edu/infrared_galleries Infrared radiation has many useful applications 1. Infrared photographs taken from a satellite with special films provide useful details of the vegetation on the Earth’s surface. 2. Infrared scanners are used to show the temperature variation of the body. This can be used for medical diagnosis. 3. Infrared remote controls are used in TVs, video cassette recorders, and other electronic appliances. 4. Infrared telescopes are used for seeing in the dark. 5. Autofocus camera has a transmitter that sends out infrared pulses. The pulses are reflected by the object to be photographed back to the camera. The following are Infrared is also used in the following devices. advantages of infrared in 1. Augmentative 5. Headphones wireless communication. communication devices 6. Home security 1. Low power systems requirement 2. Car locking system 7. Navigation systems 2. Low circuit costs a. Computers 8. Signages Mouse 9. Telephones 3. Simple circuitry b. Keyboards 10. Some toys 4. Higher security 3. Printers 4. Emergency response systems RO_Science_Grade10_Q2_LP3 8

The following are the characteristics of infrared that can be considered as disadvantages: 1. Transmitters and receivers should be directly aligned to connect and communicate. 2. It can be blocked by common materials. 3. Distance sensitive; performance drops as distance increases. 4. Weather sensitive; transmission can easily be affected by weather conditions like rain. 5. Can also be affected by light such as sunlight. ULTRAVIOLET RADIATION Ultraviolet radiation lies just beyond the violet end of the visible spectrum. Ultraviolet waves have shorter wavelengths than the visible light and carry more energy. Ultraviolet radiation is the part of the electromagnetic spectrum that consists of frequencies higher than that of the visible light but lower than X-rays. Having higher frequency, UV rays carry higher amount of energy. They can damage tissue, burn the skin How does the sun Damage skin retrieved and damage the eyes. For these reasons, fromhttps://treatcancer.com/blog/how-the- protection from such damaging rays were sun-damages-skin/ invented such like UV sunscreen/sunblock lotions and eyeglasses that could filter out these frequencies. Ultraviolet rays also have benefits. Hospitals make use of UV to sterilize medical instruments to kill harmful bacteria. Other uses of UV rays 1. Production of vitamin D in our skin 2. Sterilization of water in drinking fountains Ultraviolet (UV) Radiation retrieved from https://th.nsmart.com/GoodAndBadEffectsof 3. Identifying original from fake banknotes UVRaysYouChoose.html X-RAYS X-rays come just after ultraviolet rays. They are of shorter wavelength but carries higher energy than the UV. Short wavelength X-rays can penetrate even through metals. They are used in industry to inspect welded joints for faults. RO_Science_Grade10_Q2_LP3 9

All X-rays are dangerous because they can damage healthy living cells of the body. This is the reason why frequent exposure to x-rays should be avoided. Too much exposure to X-rays can damage body tissues and can cause cancer. The frequencies of X-rays range from 3 x 1016 to 3 x x-ray clipart retrieved from clipart- 1019 Hz. library.com/x-ray-cliparts.html GAMMA RAYS Gamma rays lie at the other end of the electromagnetic spectrum. They are the shortest in wavelength and highest in frequency. They carry the highest amount of energy, thus they are more dangerous. Gamma rays are emitted by stars and some radioactive substances. They can only be blocked with lead and thick concrete. Gamma rays are very strong that they can kill living cells. Gamma rays are used to treat Gamma ray retrieved from https://www.ck12.org/c/physics/gam cancer through the process called radiotherapy. ma-rays/lesson/Gamma-rays-MS- They are also used for sterilization of drinking PS/ water. ELABORATE: Activity 1. Expect the EM Spectrum Study the figures below and answer the questions provided. Figure 1. Electromagnetic spectrum https://simplebooklet.com/emspectrum RO_Science_Grade10_Q2_LP3 10

Activity 2. HUNT ME! Direction: Hunt the words given on the box below Put a line either horizontal, vertical or diagonal. Note: there is no space provided for two words e.g. thermal scanner I B C E L L P H O N E A R R Y D O E G L O R N E L E A O S N E I R E A N T E N N A W R E F E Y T L A T R B T Y D H O V L I L T A R X R A Y Y R H F E D O I E N E S N A T D A R A A I G I E A L O U A A D I O S E H T W M N D R O R S R I E O T R O C N L P E N A A T R E E A P W E S P Y T Y A O I A F O S N B R O A D C A S T I N G O I I D T U K O K B O Y E I O E V G E O D V N S E A T M K A A T T R O T R E O N U A B S I M K E E A Y T O H A N P E T O T R O R Y V E N R D F A A R A G A A V H N T H E E A E S A E T R A D I A T I O N A L H E S L R L A S E S O T N A K H S L E U O E R G I A E Y A V A T A A T E O O I E T N D E O E M T C N A B A N K N R T A N Y L C O A O V M M U G W S U N L I G H T T O H B O N N E A E A A O U N S P B O T Y I U E E I D A O G T S R R I L A A I H O A N A H M R S N F F H E T C T E B Y N N T M G R E O A M I L E I Y O I T H E R M A L S C A N N E R O V E N O M M 1. INFRARED 6. RADIATION 11. ANTENNA 2. RADIO 7. MICROWAVE 12. THERMAL SCANNER 3. BROADCASTING 8. OVEN 13. SUNLIGHT 4. GAMMA RAYS 9. ULTRAVIOLET 14. TELEVISION EVALUATION: 5. VISIBLE LIGHT 10. XRAY 15. CELL PHONE Direction: Choose the letter of the correct answer. EVALUATION: Direction: Choose the letter of the correct answer. 1. What type of electromagnetic wave has the longest wavelength? A. Radio waves B. Microwaves C. Infrared D. X ray 2. What type of waveband is suitable for communication over great distances? A. low frequency C. medium Frequency B. high frequency D. very high frequency 3. What converts sound into patterns of electric current variations called AF signals. A. Amplifier B. cell phone C. microphone D. telephone RO_Science_Grade10_Q2_LP3 12