How do you LIGHT UP your world ?

1. 5.3 Light How do you LIGHT UP your world ?

2. Welcome to a power point presentation on LIGHT. • We will investigate the following: • 1. What is light? • 2.What are some sources of light around us? • 3. What are opaque, transparent, & translucent objects? • 4. What is a light wave?

3. Light • Our primary source of light is the sun. • Light travels in straight lines at a speed of 186,000miles per second. • *Light waves travel fasterthan sound waves! • Light energy from the sun travels through space , reaches earth, and some of it turns to heat energy and warms the earth’s air. • Light from the sun also travels to the cells of green plants (producers) and is stored as energy. • When light reaches an object, it is absorbed, reflected, or passes through it.

4. How many sources of Light can you list and explain?

5. “Just Passing Through:” What happens when light strikes glass? Or waxed paper? Or a book? • If light travels through an object it is =transparent • If light is blocked by an object and a dark shadow is cast it is= opaque. • If some light passes through but not all and a light shadow is present it is=translucent.

6. What happens when light hits these objects? • Glass of water • School bus window • Notebook paper • Waxed paper • Plastic wrap • Tissue paper • Cardboard • Textbook • Hand lens…

7. Transparent objects: • The windows on a school bus, • A clear empty glass, • A clear window pane, • The lenses of some eyeglasses, • Clear plastic wrap, • The glass on a clock, • A hand lens, • Colored glass… • ALL of these are transparent. Yes, we can see through them because light passes through each of them.

8. Translucent objects • Thin tissue paper, • Waxed paper, • Tinted car windows, • Frosted glass, • Clouds, • All of these materials are translucent and allow some light to pass but the light cannot be clearly seen through.

9. Opaque objects: • Heavy weight paper, • Cardboard • Aluminum foil, • Mirror, bricks, buildings, • Your eyelids and hands, • Solid wood door, • All of these objects are opaque because light cannot pass through them at all. • They cast a dark shadow.

10. What is light really? • Light waves are three dimensional. • Light waves vibrate in all planes around a center line. • The waves have high points called “crests.” • Waves also have low points called “troughs.” • *The distance from one crest to the next crest is called a “wavelength.” • *The number of waves passing a given point in one second is called the “frequency.” wavelength

11. Don’t’ forget…longest waves (radio) ..to shortest waves (cosmic)

12. Radio(Longest electromagnetic waves) • Emitted by • Astronomical Objects • Radio Station Transmitters • Detected by • Ground based radio telescopes • *If you turn on a radio,, it will convert the radio wave energy into sound energy.

13. Television • Shorter than radio, also used to carry messages (pictures & sound) to our TV sets. • *We can sense the TV waves around us with our televisions.

14. Microwave • Emitted by: • Gas clouds collapsing into stars • Microwave Ovens • Radar Stations • Cell Phones • Detected by • Microwave Telescopes • Food (heated) • Cell phones • Radar (systems)

15. Infrared(Heat or Thermal)Are you a source of infrared? YES you are! • Emitted by • Sun and stars (Near) • TV Remote Controls • Food Warming Lights (Thermal) • *Everything at room temperature or above,=HEAT • Detected by • Infrared Cameras • TVs, VCRs, • Your skin

16. VisibleEachcolorisa differentsizewave.Red the longest & violet the shortest • Emitted by • The sun and other astronomical objects • Laser pointers • Light bulbs • Detected by • Cameras (film or digital) • Human eyes • Plants (red light) • Telescopes RoyG.Biv

17. UltravioletSunburn / black light • Emitted by • The sun • Tanning booths • Black light bulbs • UV lamps • Detected by • Space based UV detectors • UV Cameras • Flying insects (flies)

18. X-ray • Emitted by • Astronomical objects • X-ray machines • CAT scan machines • Older televisions • Radioactive minerals • Airport luggage scanners • Detected by • Space based X-ray detectors • X-ray film • CCD detectors

19. Gamma Ray • Emitted by • Radioactive materials • Exploding nuclear weapons • Gamma-ray bursts • Solar flares • Detected by • --Geiger counters • Gamma detectors and astronomical satellites • Medical imaging detectors

20. COSMIC Rays(The highest energy waves and the deadliest) • Cosmic rays come from deep space and can pass through the Earth.

21. Lewis Latimer • African-American • Lived from 1848-1928 • Invented a long-lasting carbon filament that made the light bulb more useful. • He also patented a threaded wooden socket for light bulbs and supervised the installation of electric streetlights in New York City, Philadelphia, Montreal, and London.

22. Isaac Newton • English • Lived from 1643-1727 • Discovered that white light was not a simple entity, but splits into a range of colors • When he passed white light through a glass prism, he noted that a spectrum of light was formed; particle theory of light • Reflecting telescope

23. Anton van Leeuwenhoek • Dutch; born in Holland • Lived 1632-1723 • Made over 500 simple microscopes • Discovered bacteria, free-living and parasitic microscopic protists

24. Galileo Galilei • Italian • Lived from 1564-1642 • Developed the refracting telescope • Developed the first known example of the microscope

25. Robert Hooke • English • Lived from 1635-1703 • Devised the compound microscope and illumination system • Discovered plant cells • Examined fossils with a microscope