• Particles in the air scatter light
• Smaller the particle, vibrates @ higher frequency (blue/violet)
• We see blue because our eyes are more sensitive to blue than to violet

Clouds have differnt sizes of droplets = scatter all frequencies of light = white

The bending of light as it goes from one medium to another.

Occurs when waves are forced to travel faster or slower due to a change in a medium.

Reflection of light occurs when light bounces off a surface.

Specular & Diffuse Reflection

Diffuse-When light strikes a rough surface and is reflected in many directions.

Specular- The surface is smooth, that is, the irregularities in the surface are small compared to the wavelength of the light. The light reflects as one beam.

Dispersion

Separation of light into colors arranged according to their frequency.

Diffraction

The bending of rays by means other than reflection or refraction.

Lunar Eclipse

When the Earth passes between the moon and the sun.

Solar Eclipse

When the moon passes between the Earth and the sun.

Shadows

Umbra- total shadow (very distinct)

Penumbra- partial shadow (fuzzy)

Total Internal Reflection

There is anangle at which the light will reflect rather than refract. This is called the critical angle - the beam will experience total internal reflection.

Holograms

3D pictures created through the interference of two parts of a laser beam.

Iridescence

Caused by destructive interference of different frequencies at different thicknesses.

Lenses

A converging lens causes parallel rays to cross. Used for cameras, telescopes, compound, microscopes, magnifying glasses, and to correct farsightedness.

A diverging lens causes parallel rays to separate. Used for peepholes in doors or viewfinders in cameras, and to correct nearsightedness.

Mirrors create a virtual image – does not have light originating from it

Real Image - An image that has light originating from it and can be projected on a wall after it has passed through a lens or reflected off a mirror. Virtual images cannot be focused on a screen.

Convex – curves outward,forms a virtual image that appears smaller and closer to the mirror than the object actually is.

Concave – curves inward, forms a virtual image that appears larger and farther away than the object is.

Lasers 

A beam of light that has the same frequency, phase, and direction. Also called coherent light

Nearsightedness

The eyeball is too long and distant objects are focused too near the lens, in front of the retina. Corrected with a diverging lens.

Farsightedness

The eyeball is too short and the image is produced behind the retina. Corrected with a converging lens.

Astigmatism

If the curvature of the eye varies, the image will not form properly. It will not be sharp.