Physics

Lenses

a curved transparent object that is smooth and regularly shaped so that when light strikes it, the light refracts in a predictable and useful way

Lenses are used in: Telescopes, microscopes, cameras etc

Converging Lenses

A lens that is thicker in the middle and thinner on the edges

Principal Focus

Point where rays converge after refraction

Optical Centre

Point at the centre of the lens

Principal Axis

Line through the optical centre and focal point

Normal Line

Imaginary Line perpindicular to principal axis

Diverging Lenses

A lens that is thinner in the middle and thicker on the edges

Principal Focus

Point where extended light rays meet after refraction

Optical Centre

Point at the centre of the lens

Principal Axis

Line through the optical centre and focal point

Normal Line

Imaginary Line perpindicular to principal axis

Parts of the human eye

Cornea

outer surface if the eye where light enters and it is completly clear

Pupil

is the dark hole in the eye that allows light to pass into th eye

Iris

A circular band of muscle that controls the pupil

Eye Problems

Hyperopia

can see distant objects clearly but not nearby objects clearly

Can be helped by converging lenses

Presbyopia

a form a far sightdness where the eye lens looses its elasticity

can be helped by converging lenses

Myopia

can see nearby objects clearly but not distant objects

Can be helped by diverging lenses

Chapter Summary

In this Chapter we learned how different types of lenses work abd how our humans eye work and why we have different problems with our eyes and why some people need lenses

Concave Mirrors

the reflection is made from the inner surface of the sphere

the center caves inward, away from you

Convex Mirrors

the reflection is made from the outer surface of the sphere

the center sticks out, toward you

Real Image

image is in front of the mirror

Virtual Image

image is behind the mirror

Light from incandescene

Producing light by heating a material up

Light from electric discharge

Produced by electricity passing through gas

Light from fluorescence

Produced by asborbing UV light and emitting it

Light from chemiluminescene

Producing light from the reaction of two chemicals

Refraction

The bending of light as they pass through different media

Unit Summary

In these chapters we learned different ways light works and how the light we use everyday is produced we also learned different types of mirrors and why certain mirros look different and act different