                                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


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 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



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   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

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      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



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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

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       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.




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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

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   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.

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                                                  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

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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


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      4. What is the best application of Microwaves?
           A. Computers                          C. Sterilization
           B. Telephones                         D. Satellite communication

      5. It is an appliance which uses microwaves to cook food.
              A. Mechanical oven                C. Oven toaster
              B. Microwave oven                 D. Traditional oven

      6. What is not a useful application infrared?
           A. Can be affected by sunlight.
           B. Some night vision goggles use IR
           C. Infrared scanners are used to show the temperature variation of the
               body.
           D. Some autofocus cameras have transmitter that sends out infrared
               pulses.

      7. What is the correct arrangement of colors of the visible light in terms of
         increasing wavelength?
             A. green, blue and red              C. blue, green and yellow
             B. red, orange and green            D. yellow, green and orange

      8. Which electromagnetic wave penetrates soft and hard tissues?
           A. Gamma rays          B. Infrared. C. UV radiation      D. X-rays

      9. Why are X-rays suitable for diagnosing one fracture and dense tumours?
           A. Because they cannot penetrate soft tissues.
           B. Because they can penetrate soft tissues and dense matter such as
              bones.
           C. Because they cannot penetrate dense matters such as muscles and
              bones.
           D. Because they can pass through soft tissues but are filtered by dense
              matter such as the bones.

      10. Which is a useful application of Gamma radiation?
            A. Used to kill cancer cells.
            B. Used in diagnosing bone fractures.
            C. Used in sterilizing water in drinking fountains.
            D. Used in the production of vitamin D in our skin.

IV.      REFLECTION

         I have learned that
         ______________________________________________________________
         ______________________________________________________________
         ______________________________________________________________
         ______________________________________________________________
         ______________________________________________________________
         _____________________________________________________________.

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      Questions:
      1. What EM wave has the shortest wavelength?
      2. What EM wave has the highest frequency?
      3. How do you compare the frequency of infrared to the frequency of Gamma
         rays?
      4. What happens to the frequency as the wavelength decreases?




                       Figure 2. EM Spectrum and its uses
               https://www.britannica.com/science/electromagnetic-spectrum

Questions:
      1. What EM wave is best applied in broadcasting?
      2. What EM wave is best for cooking?
      3. What is the use of ultraviolet radiation?
      4. What EM waves are best used in diagnosing and treating diseases?
      5. What EM waves will enable us to see what surrounds us?

EXTEND:

Activity 1. The EM wave Map
Direction: Fill in the data needed to complete the concept map below.
                             ELECTROMAGNETIC (EM)
                                    WAVES




                                APPLICATION/USES




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                                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