1. 18.3 Key Concepts
What three types of
materials affect the
behavior of light?
How does light behave
when it enters a new
medium?

2. Without light _______________ is visible.
You can see reef animals through water because light ___________ through the water between the reef and your _________.
nothing
passes
eyes

3. ______________________
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

4. Light and Materials
A transparent material _____________ light, which means it allows __________ of the light that strikes it to pass through it. .
transmits
most
The water where the
fish and coral live is
transparent.

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

6. A translucent material ____________ light.
Light and Materials
A translucent material ____________ light.
As a result, the objects you see through it look ____________ or may lack _______________; as opposed to clear or distinct.
scatters
fuzzy
detail

7. __________ materials are opaque. An opaque object does ______
Light and Materials
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.
absorbs
reflects
Most
not
allow

8. When light strikes a _________ medium, the light can be…
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

9. Interactions 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 _____________.
transferred
matter
light

10. Interactions 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.
image
copy
same
direction
rough
different

11. Which example is regular reflection? And diffuse reflection?
Interactions of Light
Which example is regular reflection? And diffuse reflection?
regular
diffuse

12. Interactions 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.
bend
angle
closer
break

13. Interactions of Light
Because the light bends, the image you see appears to be bent as well.

14. Interactions 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 ____________________.
mirage
faster
hot
curved
water

15. Light is refracted by hot air ___________ it reaches the ground
before

17. Interactions 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 _______________
one
plane
nonmetallic
window
lake

18. Horizontally polarized light reflects more
Interactions 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.
strongly
glare
sunglasses
filters

19. Interactions of Light
A vertical polarizing filter blocks light that is __________________ polarized.
horizontally
Vertical polarizing filter
Horizontal polarizing filter
Vertical wave is blocked
Horizontal wave is blocked
Vertical wave passes through filter.

20. 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

21. A scattering effect reddens the sun at ___________ and ______________
Interactions 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
sunset
sunrise
farther
shorter
longer

22. How do polarized sunglasses reduce glare?
Assessment Questions
How do polarized sunglasses reduce glare?
by scattering light as it passes through the glasses
by providing a smooth surface that light can reflect off
by absorbing all light
by blocking horizontally polarized light

23. Assessment Questions
2. An opaque material passes light through but scatters the light so that objects do not look clear. True False

24. 3. The following picture is an example of…
Assessment Questions
3. The following picture is an
example of…
Reflection
Refraction
Polarization
Scattering