Science Ch. 4.3

Explain why a rainbow can form when light shines through tiny water droplets.

When white light from the sun shines through the droplets a rainbow may appear. The water droplets act like tiny prisms, refracting and reflecting the light and separating the colors.

1. Glass causes light to bend more than air does. Which material has a higher index of refraction?

air

When light rays enter a new medium at an angle, what does the change in speed cause the rays to do?

bend and change direction

How does a lens form an image?

by refracting light rays that pass through it.

An object's position relative to the____________ determines whether a convex lens forms a real or virtual image.

focal point

A curved piece of glass or other transparent material that is used to refract light is called a(n)

lens

What is a material's index of refraction?

measure of how much a light ray bends when it enters that medium.

An image of a distant object caused by the refraction of light is called a(n)

mirage

When does refraction occur?

occurs when waves bend

describe convex lens

thicker in center than at the edges

describe concave lens

thinner in middle than at the edges

Is the following sentence true or false? The image formed by a concave lens is always upright and smaller than the object.

true

Is the following sentence true or false? The less curved a lens is, the more it refracts light.

true

Why can a concave lens produce only virtual images?

Because parallel light rays passing through the lens never meet.

What two factors determine the type of image formed by a lens?

An object's position is relative to the focal point and shape of the lens