7th Grade Chapter 5 Lesson 2


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7th Grade Chapter 5 Lesson 2

  1. 1. Pgs. 159-167 For Student Use Only 7 th Grade Chapter 5 Lesson 2
  2. 2. Question 1 What is the atmosphere good for? <ul><li>A. Protect life from radiation from the sun </li></ul><ul><li>C. Keep temperatures constant </li></ul><ul><li>B. Contain enough oxygen </li></ul><ul><li>D. Disperse water throughout the world </li></ul>
  3. 3. Key <ul><li>1) A,B,C,D </li></ul>
  4. 4. Waves are everywhere <ul><li>Student generated ideas: </li></ul><ul><li>How are the 2 pictures related? </li></ul><ul><li>1. Tyler, Sanitago, Matthew- sun has rays which are like waves and the water has waves </li></ul><ul><li>2. Katy, Katlyn- sun has heat waves you can feel and water has ripples after you touch it </li></ul>
  5. 5. Waves are everywhere <ul><li>Waves </li></ul><ul><ul><li>Waves carry energy </li></ul></ul><ul><ul><li>Waves need a medium to travel through- (any substance) called a wave medium </li></ul></ul><ul><ul><li>Electromagnetic Wave- </li></ul></ul><ul><ul><ul><li>Made of electric and magnetic fields </li></ul></ul></ul><ul><ul><ul><li>Fields vibrate back and forth </li></ul></ul></ul>http://www.astronomynotes.com/light/emanim.gif
  6. 6. Parts of the waves: <ul><li>Student generated ideas: </li></ul><ul><li>What parts of the waves are listed in the pictures? </li></ul>
  7. 7. Waves are everywhere <ul><li>Parts of Waves: </li></ul><ul><ul><li>Wave Pulse: a single rise or depression in a series of waves </li></ul></ul><ul><ul><li>Crest- high point of wave </li></ul></ul><ul><ul><li>Trough- lowest point of wave </li></ul></ul><ul><ul><li>Wave Train- series of waves </li></ul></ul><ul><ul><li>Frequency- number of complete waves that pass a given point at a certain time </li></ul></ul><ul><ul><li>Wavelength- distance from one crest to another crest </li></ul></ul>http://www.astronomynotes.com/light/emanim.gif
  8. 8. Waves are everywhere <ul><li>Student generated ideas: </li></ul><ul><li>How many of these waves do you use everyday? </li></ul>http://www.hermes-program.gr/img/figures/emrinfo_1_en.jpg
  9. 9. Waves are everywhere <ul><li>Types of Electromagnetic Waves: </li></ul><ul><ul><li>Infrared Rays: caused by higher amounts of energy- we sense as heat </li></ul></ul><ul><ul><li>Radio Waves: FM, AM (short-band) or VHF (VERY high frequency) </li></ul></ul><ul><ul><li>Microwaves: lower portion of radio waves (RADAR senses this) </li></ul></ul><ul><ul><li>Ultraviolet: higher frequency </li></ul></ul>
  10. 10. Waves are everywhere <ul><li>Types of Electromagnetic Waves: </li></ul><ul><ul><li>Flourescent- turns UV light into visible light (think florescent lights) </li></ul></ul><ul><ul><li>X-rays: high frequency rays and can penetrate many materials </li></ul></ul><ul><ul><li>Gamma Rays: extremely energetic can be dangerous </li></ul></ul>
  11. 11. Waves are everywhere <ul><li>Student generated ideas: </li></ul><ul><li>How many of these waves do you think are screened by the sun? </li></ul>http://www.hermes-program.gr/img/figures/emrinfo_1_en.jpg
  12. 12. Waves are everywhere <ul><li>Electromagnetic Waves from Sun: </li></ul><ul><ul><li>Most radiation (99%) from the sun is in the optical window </li></ul></ul><ul><ul><ul><li>Windows are bands of frequencies </li></ul></ul></ul><ul><ul><ul><ul><li>Radio and Optical Window </li></ul></ul></ul></ul><ul><ul><li>Atmosphere stops much radiation </li></ul></ul>
  13. 13. Waves are everywhere <ul><li>Layer of the atmosphere: </li></ul><ul><li>Thermosphere- hottest region </li></ul><ul><li>Ionsphere- found in thermosphere and mesosphere and has a high concentration of positive </li></ul><ul><li>Stratosphere- home to ozone layer </li></ul><ul><ul><li>Ozone Layer- is made of O 3 that is turned into O 2 when energy hits it </li></ul></ul>http://ds9.ssl.berkeley.edu/lws_gems/3/images_3/layat510.jpg
  14. 14. Waves are everywhere <ul><li>Reflected Radiation: </li></ul><ul><li>50% of suns energy reaches earth reaches Earth </li></ul><ul><ul><li>ON EARTH: </li></ul></ul><ul><ul><ul><li>47% absorbed by sun </li></ul></ul></ul><ul><ul><ul><li>3% is reflected off Earth into space </li></ul></ul></ul><ul><ul><li>IN ATMOSPHERE: </li></ul></ul><ul><ul><ul><li>25% absorbed by atmosphere </li></ul></ul></ul><ul><ul><li>Atmosphere: </li></ul></ul><ul><ul><ul><li>25% reflected immediately into space </li></ul></ul></ul>http://ds9.ssl.berkeley.edu/lws_gems/3/images_3/layat510.jpg