Why does a curved mirrored surface (like the Chicago Bean

1
Why does a curved mirrored surface (like the
Chicago Bean in Millennium Park) produce a
distorted image (sometimes making things look
smaller and sometimes making things look bigger?
2
Reflection of Light
Recall that when a wave reaches a boundary
between two media, some or all of the wave
______________ (or _________).
bounces back
reflects
Law of Reflection
3
Which ray is the correct reflected ray?
This law is valid for all surfaces. flat,
curved, smooth, rough, etc
Animation and Diagrams from The Physics
Classroom Website
Demo Reflect LASER off mirrors with fog or dust
in the air
4
The Law of Reflection also applies to billiards
or putt-putt golf!
5
An Application of Reflection Mirrors
Plane
________ (flat) mirror A Ray Diagram is

used to find the
location of
the
image formed when

an object is placed

in front of a plane

mirror
An Animation Showing the formation of the image
6
EXAMPLE Find the location of the image of the
candle by drawing a Ray Diagram.

• Use the Law of Reflection to draw in the
  reflected rays.
• The image is located at the point where the
  reflected rays of light intersect. If the rays
  dont converge, like in this case, to find the
  image, we use __________ ________ to extend the
  reflected rays backwards to the point where it
  appears that they came from

dashed lines
image
7
size

• The image is the same ______ as the object and is
  the same __________ away from the mirror as the
  object.
• The image appears to be _________ the mirrors
  surface and is called a _________ image.
  ________ images are images which are formed in
  locations where light does not actually reach.
  It only appears that light came from the images
  position.

distance
behind
virtual
Virtual
8
Convex Mirrors
C Center of Curvature F Focal Point, halfway
between C and the
mirror

• Ray Diagram Shortcuts Instead of using a
  protractor and the Law of Reflection, the
  following rays can be used to find the image
• A ray drawn towards C bounces back on itself.
• A ray drawn parallel to the axis will reflect as
  though it had originated at F.

9
EXAMPLE Find the location of the image of the
arrow by drawing a Ray Diagram.
image
diverge

• The reflected rays ____________, so again we must
  extend those rays __________ the mirror using
  dashed lines, to find where the rays appear to
  originate from.

behind
10
Another ray that can be drawn is
A ray heading towards F will be reflected out
parallel to the axis.
11
Convex Mirror Images
Images formed by convex mirrors are ALWAYS
_________, _________ than the object, and
__________. Applications
smaller
upright
virtual
Car Mirrors Objects
in Mirror are Closer than they Appear
Museum Mirrors
Store Anti-Shoplifting Mirrors
12
(No Transcript)
13
Narcissus, the turkey??
14
Concave Mirrors
Concave mirrors are mirrors that are curved
inwards (or caved in). While convex mirrors
always __________ light, concave mirrors can
either _________ or __________ light, depending
on the location of the object. Concave mirrors,
then, can produce various types and sizes of
image.
diverge
converge
diverge
15
(No Transcript)
16
Ray Diagram Example Find the location of the
image of an object (an arrow) that is located
between the Focal Point, F, and the mirror.
This time, a parallel ray of light reflects
through F, and again, a ray through C bounces
back on itself.
image
C
F
Image is _______ and _______.
larger
virtual
17
Convex vs. Concave Virtual Images
Applications
Cosmetic Mirrors
Fun House Mirrors
18
Ray Diagram Example What happens to the
reflected light if an object such as a light bulb
is placed at F?
All rays are reflected __________
(they dont __________), so there is _________!
parallel
intersect
NO image
19
Applications Car Head Lights, Flashlights,
Spotlights.
Satellite Dishes Rays are reversed!
20
Ray Diagram Example Find the location of the
image of an object (an arrow) that is located
between the Focal Point, F, and the center of
curvature, C.
larger
inverted
Image is ________ and _________
image
C
F
real
The image is also a ______ image, since the
reflected rays of light actually converged to a
point. The image will be
projected on a ________ placed at that point.
screen
21
Object between C and F away from mirror
ANIMATIONS
Object lt F away from mirror
Object C away from mirror
Object gt C away from mirror
22

• DEMOS
• Concave mirrors producing real images of objects
  outside the window.
• More curved mirrors have _______ focal lengths
  and will produce ________ images.
• The Mirrors Mirage
• A 3-D _______ image made
  with 2 concave mirrors.

shorter
smaller
real
23
Website Ray Diagrams for Mirrors
http//www.phy.ntnu.edu.tw/ntnujava/index.php?top
ic48
Website Solar Death Ray (Mythbusters tried
this) http//www.combobulate.com/solardeathray.ph
p