1. LIGHT!

2. What is light? Light is nature’s way of transmitting energy.
This energy comes in 2 forms: particles and waves.
The particles of light are called PHOTONS and each photon carries a certain amount of energy.
Photons are what make up light waves.

3. Sooo….is light a particle or a wave?
This is a difficult question – the answer is that in some situations light behaves as a particle and in others it behaves as a wave.

4. Properties Of Light

5. REFLECTION
Every object sends light to your eyes. Some can produce its own light – sun, light bulbs, candles, fireflies, fish, lightning. This is called luminescence.
Other objects take the light that’s produced and reflects it in certain wavelengths.
To model light’s path, we use light “rays” to represent light traveling through space.

6. TYPES OF REFLECTION
Diffuse reflection – reflection off of a bumpy surface
Smooth surface reflection – reflection off of a smooth surface

7. MIRRORS
Mirrors that bulge = convex (the outside of a spoon) (like funhouse mirrors)

8. Mirrors that indent = concave (the “caved in” side of the spoon)

9. COLOR
Color is produced because light produces different wavelengths. The color we see on an object is the wavelength that is reflected off of the object. All other wavelengths (colors) are being absorbed.

10. REFRACTION
Refraction is what happens when light waves pass from one medium to another.
When this happens with light, many times you see a MIRAGE.

11. LIGHT MOVING FROM AIR TO GLASS
light ray bends inward (towards the “normal”)

12. LIGHT MOVING FROM GLASS TO AIR
light ray bends outward (away from the “normal”)

13. THE EYE
If the lens refracts light differently, nearsightedness or farsightedness results.
Nearsighted – can’t see far (myopia)
Farsighted – can’t see near (hyperopia)
These result in needing corrective lenses

14. Nearsighted people have lenses in their eyes that focus light in front of the retina.
They need DIVERGING LENSES (bends light outward)
Also called concave lenses

15. Far sighted people have lenses in their eyes that focus light behind the retina.
They need CONVERGING LENSES (bends light inwards).
Also called convex lenses

16. Physiology of the Eye (3 min)
Light: Visible and Invisible (6 min)