18.3 Behavior of Light

18.3 Key Concepts• What three types of

materials affect the

behavior of light?

• How does light behave

when it enters a new

medium?

18.3 Behavior of Light

Without light _______________ is visible.

You can see reef animals through water because light ___________ through the water between the reef and your _________.

nothing

passes

eyes

18.3 Behavior of Light

Light and Materials

•How light behaves when it strikes an object depends on many factors, including the __________________ the object is made of…

• Materials can be…• ______________________• ______________________• ______________________

material

transparent

translucent

opaque

18.3 Behavior of Light

A transparent material _____________ light, which means it allows __________ of the light that strikes it to pass through it.

.

Light and Materials

The water where the

fish and coral live is

transparent.

transmitsmost

18.3 Behavior of Light

.

Light and Materials

While riding on a bus, you can see buildings and trees outside because the bus ______________ are transparent.windows

18.3 Behavior of Light

A translucent material ____________ light.

As a result, the objects you see through it look ____________ or may lack _______________; as opposed to clear or distinct.

Light and Materials

scatters

fuzzy detail

18.3 Behavior of Light

An opaque material either ___________ or ______________ all of the light that strikes it.

__________ materials are opaque.

An opaque object does ______

____________ any light to pass

through it.

Light and Materials

absorbs

reflects

Most

not

allow

18.3 Behavior of Light

Interactions of Light

When light strikes a _________ medium, the light can be…• __________________• __________________• __________________

If transmitted, or _________________, it can be refracted, polarized, or scattered.

new

reflected

absorbed

transmitted

passed through

18.3 Behavior of Light

Recall that when light encounters matter, some or all of the energy in the light can be ________________ to the matter.

Just as light can affect matter, _____________ can affect _____________.

Interactions of Light

transferred

matter

light

18.3 Behavior of Light

Reflection

An ____________ is a ____________ of an object formed by reflected (or refracted) waves of light.

Regular reflection occurs when parallel light waves strike a surface and reflect all in the __________ _____________________

Diffuse reflection occurs when parallel light waves strike a ____________, uneven surface and reflect in many ________________directions.

Interactions of Light

image copy

same direction

roughdifferent

18.3 Behavior of Light

Which example is regular reflection? And diffuse reflection?

Interactions of Light

regular diffuse

18.3 Behavior of Light

Refraction

A light wave can refract, or ____________, when it passes at an ______________ from one medium into another.

Refraction makes underwater objects appear _______________ and larger than they really are.

Refraction can also make an object appear to _____________ at the surface of the water.

Interactions of Light

bend

angle

closer

break

18.3 Behavior of Light

Because the light bends, the image you see appears to be bent as well.

Interactions of Light

18.3 Behavior of Light

Refraction can also sometimes cause a ______________, a false or distorted image.

• Mirages occur because light travels ______________ in ________ air than in cooler, denser air.

• Refraction causes some of the light to follow a __________________ path, rather than a straight path to the ground.

• Light that reaches your eyes after traveling in this manner can look as if it was reflected from a layer of ____________________.

Interactions of Light

mirage

fasterhot

curved

water

18.3 Behavior of Light

Light is refracted by hot air ___________ it reaches the ground

before

18.3 Behavior of Light

18.3 Behavior of Light

Polarization

Light with waves that vibrate in only ________ ___________ is polarized light.

Polarized light may occur when light reflects from a ________________ flat surface, such as a…

– __________________– surface of a _______________

Interactions of Light

one

plane

nonmetallic

window

lake

18.3 Behavior of Light

Polarization• Horizontally polarized light reflects more

____________ than the rest of the sunlight,

producing a _________________

• Polarized _________________ have vertically

polarized _______________ to block the

horizontally polarized light.

Interactions of Light

strongly

glare

sunglasses

filters

18.3 Behavior of Light

A vertical polarizing filter blocks light that is __________________ polarized.

Interactions of Light

Vertical polarizing filter

Horizontal polarizing filter

Vertical wave is blocked

Horizontal wave is blocked

Vertical wave passes through filter.

horizontally

18.3 Behavior of Light

Scattering

In scattering, light is ____________________ as it passes through a medium.

• Most of the particles in the atmosphere are very _____________.

• Small particles scatter ________

wavelength _________ light more

than light of longer wavelengths.

• Blue light is scattered in all

directions more than other colors

of light, which makes the _________ appear blue.

redirected

small

shorter

blue

sky

18.3 Behavior of Light

A scattering effect reddens the sun at ___________ and ______________

• When the sun is close to the horizon, sunlight travels ____________________ through the atmosphere.

• By the time the sunlight

reaches your eyes, most

______________-wavelength

light has been scattered.

• The remaining light consists

mostly of ____________ wavelength reds and oranges

Interactions of Light

sunset

sunrise

farther

shorter

longer

18.3 Behavior of Light

Assessment Questions

1. How do polarized sunglasses reduce glare? a. by scattering light as it passes through the glasses

b. by providing a smooth surface that light can reflect off

c. by absorbing all light

d. by blocking horizontally polarized light

18.3 Behavior of Light

Assessment Questions

2. An opaque material passes light through but scatters the light so that objects do not look clear.

TrueFalse

18.3 Behavior of Light

Assessment Questions

3. The following picture is an

example of… a. Reflection

b. Refraction

c. Polarization

d. Scattering