Notes: Light

1. Notes: Light Read pgs 52-60. Objective: Know how lenses affect light.

2. Light • Visible light is one type of energy found in the electromagnetic spectrum. Video: Nature of Light

3. Light • We can see visible light because our eyes are made to match its wavelength.

4. Color • The main colors of visible light are red, orange, yellow, green, blue, indigo, and violet. ROY G BIV. Video: Visible Light

5. Color • The three primary colors of light that can be combined to form any other color are red, blue, and green. Video: Primary Colors

6. Color • When light strikes an object, the light can be reflected, transmitted, or absorbed. • The colors we see are the light that is being reflected, the rest are absorbed. Video: Color

7. Transparent • A transparent material transmits most of the light that strikes it. • When light hits a translucent material, the particles absorb it but then send it back out, until the light finally passes through to the other side.

8. Translucent • A translucent material scatters light as it passes through, just like smoke, fog, and clouds. • You can usually see something behind translucent material, but the details are blurred.

9. Opaque • An opaque material reflects or absorbs all of the light that strikes it. • You cannot see through opaque materials because light cannot pass through them. Video: Opaque

10. Light goes straight • Light travels in a straight line unless it interacts with a medium. • The material through which a wave travels is called a medium. • Light can be reflected, refracted (bent), scattered, or absorbed.

11. Reflection • Reflection: when an object or wave bounces back off a surface through which it cannot pass.

12. Law of Reflection • The law of reflection states that the angle of incidence equals the angle of reflection. Video

13. Refraction • Refraction: the bending of light waves due to change in speed. Video

14. Refraction • Refraction: when light rays enter a medium at an angle, the change in speed causes the rays to bend, or change direction. • Refraction is what causes white light to break into colors like in a rainbow. Video

15. Mirrors • Mirror: a plane sheet of glass or similar material with a smooth, shiny coating on one side.

16. Lenses • Lens: a curved piece of glass or other transparent material that refracts light. • A lens forms an image by refracting light rays that pass through it. Video

17. Convex Lens • Convex lens: thicker in the center than at the edges that focuses rays of light (magnify). • Used in eyeglasses to correct for farsightedness. • Examples are microscopes, magnifying glasses, and telescopes.

18. Convex Lens • Used in things like microscopes, magnifying lenses, and in some telescopes.

19. Concave Lens • Concave lenses: thinner in the center and thicker at the edges (minimize). • Concave lenses form virtual images that are usually smaller than the original. • Used in eyeglasses to correct for nearsightedness. Video

20. Concave lens • Mainly used to correct vision in eye glasses and contact lenses.