1 / 35

Light

Light. Chapter 13. Ch13 Sec 1 The Behavior of Light. Light and Matter. Objects must reflect light to be seen. Opaque materials do not allow light to pass through them; they only absorb and reflect light. Light and Matter. Objects must reflect light to be seen.

easter
Download Presentation

Light

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Light Chapter 13

  2. Ch13 Sec 1The Behavior of Light

  3. Light and Matter • Objects must reflect light to be seen. • Opaque materials do not allow light to pass through them; they only absorb and reflect light

  4. Light and Matter • Objects must reflect light to be seen. • Opaque materials do not allow light to pass through them; they only absorb and reflect light • Some light passes through translucent materials.

  5. Light and Matter • Objects must reflect light to be seen. • Opaque materials do not allow light to pass through them; they only absorb and reflect light • Some light passes through translucent materials. • Transparent materials allow almost all light to pass through them; only a little light is absorbed and reflected.

  6. Reflection of light • Reflection of light – a light wave strikes an object and bounces off. • Law of Reflection – angle at which light strikes a surface is the same as the angle at which it is reflected

  7. Regular Reflection • Regular reflection – reflection of light waves from a smooth surface

  8. Diffuse Reflection • Diffuse reflection – reflection of light waves from a rough surface

  9. Refraction of Light • Refraction of light - change in the speed of a light wave when it passes from one material to another

  10. Index of refraction • The index of refraction indicates how much a material reduces the speed of light; the more light is slowed, the greater the index of refraction.

  11. Prisms • Separate white light into visible spectrum based on light wavelength

  12. Rainbows • Caused by water droplets refracting wavelengths of sunlight

  13. Chapter 13 Section 2Light and Color

  14. Colors… • Colors are determined by wavelength of light an object reflects. • White objects reflect all colors of visible light. • Black objects absorb all colors of visible light.

  15. Colors… • Colors are determined by wavelength of light an object reflects. • White objects reflect all colors of visible light. • Black objects absorb all colors of visible light. • Filter – is a transparent material that absorbs all colors except the color or colors it transmits • Filters can make objects appear to be different colors.

  16. Seeing Color • Light enters the eye and is focused on the retina. • Retina – made up of two types of cells that absorb light

  17. Seeing Color… • Light enters the eye and is focused on the retina. • Retina – made up of two types of cells that absorb light • Cones – distinguish colors and detailed shapes; most effective in daytime vision • Rods – sensitive to dim light; most effective in nighttime vision

  18. Colorblindness Tests Normal color: yellow square & faint brown circle Colorblind sees: yellow square Test Name: Ishihara Test Colorblind sees: the number 17 Normal Color sees: the number 15

  19. Colorblindness • Results from when one or more sets of cones do not function properly

  20. Mixing colors • Pigment – colored material that absorbs some colors and reflects others

  21. Mixing colors • Pigment – colored material that absorbs some colors and reflects others • Primary colors of light – Red, Green, and Blue • Primary colors of pigment – magenta, cyan, and yellow

  22. Mixing colors • Pigment – colored material that absorbs some colors and reflects others • Primary colors of light – Red, Green, and Blue • Primary colors of pigment – magenta, cyan, and yellow • Primary colors of light are additive colors – combine to form white • Primary colors of pigments are subtractive colors – combine to form black, the absence of reflected light

  23. Producing Light Chapter 13 Section 3

  24. Incandescent lights • Hot tungsten wire glows; gives off light and heat

  25. Fluorescent lights • Electrons collide with gas atoms, releasing ultraviolet radiation absorbed by phosphorus lining the bulb; gives off light Why are these better than Incandescent bulbs? • Less energy used • longer lasting

  26. Neon lights • Tubes filled with gas (usually neon) produce light from electron collisions; different colors can be made by adding different gases

  27. Sodium-vapor lights • Heated neon gas glows and warmth turns sodium into a vapor, producing a yellow-orange glow; used for outdoor lighting.

  28. Tungsten-halogen lights • Have a filament and gas enclosed in a glass bulb to produce intensely bright light

  29. Lasers • Light beam produced when identical atoms send off identical light waves; can be made from gases, liquids, or solids • FYI – LASER – Light Amplification by Stimulating Emissions of Radiation

  30. Lasers • Light beam produced when identical atoms send off identical light waves; can be made from gases, liquids, or solids • Lasers produce coherent light – waves of some wavelength are aligned, and travel same direction • Incoherent light – waves of multiple wavelengths are not aligned, travel in many directions

  31. Using Light Chapter 13 Section 4

  32. Holography • Process used to create a three-dimensional photographic image of an object • Illuminating objects with laser light produces holograms. • Holographic images are difficult to copy.

  33. Optical Fibers • Use a process called Total Internal Reflection in order to transfer information coded in light beams. • Total internal reflection – light strikes a surface between two materials and is completely reflected back to the first material.

  34. Total internal reflection

More Related