Reflection and
Refraction
TEKS 5.8B
Objective 3: The student will demonstrate an
understanding of the physical sciences
5.8 – The student knows that energy occurs in many
forms:
(B) identify and demonstrate everyday examples
of how light is reflected, such as from tinted
windows, and refracted, such as in cameras,
telescopes, and eyeglasses
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Every second of every day our eyes detect and
interpret rays of light – whether that light is
coming from a natural source like the sun, or an
artificial source like a lamp.
One of the properties of light is that it travels in
a straight line, unless it is acted on by some
external force or condition.
next
However, sometimes our eyes can be fooled by
the reflection and refraction of light. When
interfered with, the path of light rays can be
bounced or appear to be bent away from the
original object making it seem larger or smaller
than it really is.
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Reflection
When light strikes a surface and is redirected back
to its point of origin, this is reflection. We can see
objects when they reflect light, and the reflected
light enters our eyes.
Most objects reflect some of the light that hits
them.
Smooth, shiny surfaces that absorb very little light,
will reflect light at almost the same angle that the
light hits it.
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Mirrors reflect images of objects because light
rays bounce off an object, travel in a straight
line to a mirror, bounce off the mirror, and then
travel to the eye of the observer.
Light beams
Mirror
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Refraction
When the path of the light rays change directions
and appear to bend we call it refraction.
occurs when light passes from one substance
to another of a different density
(for example, from air to water)
amount of refraction depends on the angle the
light enters the new substance and the
difference in the densities of the two
the greater the angle, the more the light ray
will be bent
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Refracting telescopes
and regular cameras
use lenses to gather
and focus light.
Reflecting telescopes
gather and focus
light with mirrors.
In a reflecting
telescope, the
observer sits inside
the telescope, at the
focal point of the
reflected light.
next
Decide whether each object below best represents
reflection or refraction. Click on your answer to find out
if you are correct.
reflection
reflection
refraction
reflection
refraction
reflection
refraction
reflection
refraction
reflection
refraction
refraction
next
You are correct – This picture illustrates
reflection. Light bounces off of the object
and does not pass through.
Back to pictures
You are correct. This picture illustrates
refraction. As light passes through the object
it is bent by the denser substance.
Back to pictures
Sorry, that is not correct
Back to pictures
One way solid objects are classified is by how
much light is allowed to pass through that object.
A transparent object lets all of the light pass
through.
A translucent object lets some light pass through.
An opaque object lets none of the light pass
through.
transparent
translucent
opaque
next
You are about to see several objects. Your job is to
decide if they are mostly transparent, translucent or
opaque After you decide, click on the object to see if you are
correct. Some pictures have two options.
The computer is opaque. No
The
brick
wall
is
These
This
sphere
pens
are
is
light
is
passing
through,
so you
This
window
is
transparent.
opaque.
You Enough
translucent.
transparent.
You
can
light it.
This
lampshade
is behind
cannot
see
anything
You
can clearly
see
the you
cannot
see
any
passes
clearly
through
see
the
to
man
allow
translucent.
Someisof the
However,
the other
screen
image
on
the
side
part
of
the
boy
to
inside.
see
some
The
of
man,
the
inside,
ofwhy
light passes through,
but you
not
transparent.
That
is
because
all
ofopaque.
thetolight
is
through
the
wall.
but
course,
not
enough
is
see
all of
it. see the man’s face
can
clearly
passing
through.
everything
clearly.
behind the screen.
(NOTE: The next picture will come in automatically – do not click again to
advance. Click only to check your answer.)
next
Now, try answering these
questions:
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Unless acted upon, how does light travel?
A. Bent at a 500 angle.
B.
In a straight line.
C.
In a curved arch.
D. Light doesn’t have a preferred path.
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Answer B is correct:
Light travels in a straight line.
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These answers are not correct because –
Answer A – Although light is often bent at a 500
angle, that only happens when something acts upon
it to make it change its path.
Answer C – Light does not usually travel in an arch.
Answer D – Light does have a preferred path – a
straight line.
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All the following are examples of light being
refracted EXCEPT —
A
B
C
D
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Answer choice D is correct. The mirror is
using reflection to bounce light off of its
surface.
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These answers are not correct because:
Answer A – Look at the bent light rays. A
rainbow is the result of light being
refracted.
Answer B – Look at the bent light rays. A
prism bends light.
Answer C - The straw looks bent in this
picture. It is an example of refraction,
not reflection.
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Which answer below names two conditions in
which refraction can occur?
A.Opaque and transparent
B.Transparent and black
C.Translucent and transparent
D.Translucent and opaque
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Answer choice C is Correct:
In order for light to pass through an object
and be refracted, the object must be
transparent (see-through) or translucent
(semi-transparent).
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These answers are not correct because:
Answer A - An opaque object would not allow light
to pass through it.
Answer B – A black surface would not necessarily
allow light to pass through it.
Answer D – An opaque surface would not allow light
to pass through it.
next
In this picture, the straw
appears to be bent. This is
because –
A.milk is an opaque substance.
B.light is being refracted.
C.it is a magic trick.
D.light is being reflected.
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Answer B is correct.
The straw appears to be bent because light
is being refracted as it passes through the
air into the liquid.
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These answers are not correct because:
A. An opaque substance – if the liquid were
opaque, we would not be able to see the
straw.
B. A magic trick – it is not a trick that the light
is being bent, or refracted, as it moved
through the liquid
C. Light being reflected – although some light
may be reflected by the glass, that is not the
reason why the straw appears to be bent.
next
Which of these objects best illustrates reflection?
A. Prism
C. Window
B. Rose Quartz
D. Paper
next
Answer C is correct.
The smooth surface of the window is
reflecting the image of nearby buildings.
next
These answers are not correct because:
A – Prism –light is being refracted as it passes
through the prism
B - Rose Quartz – the surface of this rock is
too rough to reflect light
D -Paper – since paper is opaque, light would not
bounce off or be refracted.
next
Look at the objects below. Which one uses
refraction?
A
B
C
D
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Answer Choice C is CORRECT.
A rainbow uses refraction. The light is bent
as it passes through the air and water
droplets.
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Answer choice A, B, and D are not correct.
Mirrors use reflection of light in order to
see an object, not refraction.
The
End
Resources for images:
Transparent screen:
www.computeramerica.com/.../2005/2005-04-04.htm
Transparent watch:
www.swatchforum.com/curiosities.html
Virtusphere:
www.virtusphere.net/product.htm
Opaque pitchers:
www.guild.com/artitem/30336.html
Transclucent pen
www.promotional-pens.us/promotional-pens/basi...