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Ch 11
Reflecting Light off a Plane Mirror
p. 313
Types of Mirrors (3)
1) Plane: flat fg 1 p. 313
law of reflection: the angle of incidence = the angle of reflection
incident ray (in): the ray (light beam) of light that travels to the reflecting surface
reflected ray: the ray of light that bounces off a reflecting surface
normal: a line drawn perpendicular (90°) from the point of incidence of the reflecting surface
angle of incidence: the angle between the incident ray and the normal
angle of reflection: the angle between the reflected ray and the normal
http://www.youtube.com/watch?v=IjIo8im38gA
Sec. 11.2 Reflecting Light off Surfaces
p. 316
Specular (regular) reflection:
light reflects off a smooth, shiny surface, flat
ex: fg 1a p. 316
often produces an image (picture)
ex: mirror, clear water, shinny metal
http://www.youtube.com/watch?v=Qr8exoX-uE0&feature=related
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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image appears behind the mirror, right-side up but backwards ex: fg 3 p. 317:
Diffuse Reflection:
light hits an irregular surface and is scattered in all directions → no image produced
http://www.youtube.com/watch?v=y7xJ28ghzkI&feature=related
still obeys the angle of incidence = angle of refection law
fg 1b p. 316
do not see a reflection:
ex: looking into green
grass
diffuse reflection easier on eyes: ex: lamp shades, stucco roofs, frosted
bulbs
HW:
Read 11.3
cyu 11.2
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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Ch 11
Reflecting Light off a Plane Mirror
p. 313
________of Mirrors (3)
1) Plane: ________ fg 1 p. 313
law of __________: the angle of ______________= the angle of _____________
incident ray (in): the __________(light beam) of light that travels _________the reflecting surface
__________ray: the ray of light that _____________off a reflecting surface
___________: a line drawn perpendicular (90°) from the point of incidence of the reflecting surface
______of incidence: the angle between the incident ray and the ____________
angle of ___________: the angle between the ______________ray and the normal
http://www.youtube.com/watch?v=IjIo8im38gA
Sec. 11.2 ___________Light off Surfaces
p. 316
_____________(regular) reflection:
light reflects off a _________, shiny surface,
flat ex: fg 1a p. 316
often produces an ___________(picture)
ex: mirror, clear water, shinny metal
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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image appears ____________the mirror, right-side up but ________________
ex: fg 3 p. 317:
_________Reflection:
light hits an______________surface and is ____________in all directions → ______image produced
http://www.youtube.com/watch?v=y7xJ28ghzkI&feature=related
still obeys the angle of incidence = angle of refection ___________
fg 1b p. 316
do _______ see a
reflection:
ex: looking into green
grass
diffuse reflection easier on eyes: ex: lamp ___________, stucco roofs,
frosted bulbs
HW:
Read 11.3
cyu 11.2
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Sec. 11.3 Describing Images
p. 319
image: likeness of object (picture)
ex:
formed at back of eye
formed on a screen
fg 1 p. 319
optical device: produces an image
ex: overhead machine
Characteristics of Images:
table 1 p. 320
1) Size: a) smaller then the object
b) larger then the object
c) same size as the object
2) Attitude: a) upright (right side up)
b) inverted (upside down)
3) location of image (many possibilities)
a) on the side of the lens opposite the object
b) closer to the optical device then to the object
c) behind mirror, in front of mirror, etc
4) Type: a) real image (can be placed on a screen)
b) virtual image (can be seen only by looking at or though an optical
device)
ex: microscope
Lab 11.5 Curved Mirrors
p. 323
Types of mirrors (3)
a) flat (plane)
b) convex: reflecting surface is on the outside of the curved surface
fg 1 p. 323
ex: back of a spoon
c) concave: reflecting surface is on the inside of the curved surface
fg 2 p. 323
ex: shaped like a cave, inside of the spoon
Sec. 11.6
Using Curved Mirrors 2 kinds
1) concave mirror
fg 1 p. 326
p. 326
shaped like a cave
principal focus: position where reflected parallel light rays come together
focal length:
the distance from the principal focus to the middle of the mirror
principal axis: a line through the center of the mirror that includes the principal focus
focuses parallel light rays to principal focus
fg 1 p. 326
when object is beyond the principal focus  real image in front of the mirror  can appear on
a screen
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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2) convex mirror
fg 2 p. 326
shaped like a vex
principal focus: position where parallel light rays appear to reflect from: rays diverge (spread apart)
spreads light rays out  virtual image behind the mirror  can not be put on a screen
USING CONCAVE MIRRORS fg 3 p. 326
concave mirror gathers light from distant place & focuses it on: your eye, telescope, camera film, digital camera
fg 4 p. 327
concave cosmetic / make-up mirror
object is placed inside the principal focus of a concave mirror  virtual, upright, farther from the mirror then the object,
enlarged image
Using Convex Mirrors
Curved surface reflects light from all parts of a room or area into your eye  large field of view
Ex: fg 5a p. 327
Ex: surveillance mirrors
Ex: car side mirrors
fg 6 p. 327
 upright, smaller, farther away images
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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Sec. 11.3 Describing ____________ p. 319
image: ___________ of object (picture) fg 1 p.
ex:
formed at back of eye
formed on a screen
_________device: produces an ________
ex: overhead machine
________________ of Images: table 1 p. 320
1) ________: a) smaller then the object
b) larger then the object
c) _________size as the object
2) __________: a) upright (right side up)
b) __________(upside down)
3) ___________of image (many possibilities)
a) on the side of the lens _____________the object
b) closer to the optical device then to the object
c) behind mirror, in front of mirror, etc
4) ____________:
a) __________image (can be placed on a __________)
b) _________image (can be seen only by looking at or
though an optical _____________)
ex: ____________
Lab 11.5 Curved Mirrors
p. 323
Types of mirrors (3)
a) flat (___________)
b) __________: reflecting surface is on the outside of the curved surface
fg 1 p. 323
ex: ____________of a spoon
c) ____________: reflecting surface is on the inside of the curved surface
fg 2 p. 323
ex: shaped like a ________, inside of the spoon
Sec. 11.6
Using _________Mirrors
1) _____________mirror
fg 1 p. 326
2 kinds p. 326
shaped like a cave
______focus: position where reflected parallel light rays come _______
focal __________: the ____________from the principal focus to the middle of the mirror
principal _______: a line through the center of the mirror that includes the principal ____
focuses parallel light rays to principal ______
fg 1 p. 326
when __________is beyond the principal focus  ______image in front of the mirror  can
appear on a ______
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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2) _________mirror
fg 2 p. 326
shaped like a vex
principal _________: position where parallel light rays appear to _____________from: rays _________(spread apart)
________light rays out  ________image behind the mirror  can ______ be put on a screen
USING CONCAVE MIRRORS fg 3 p. 326
concave mirror gathers light from ______________place & focuses it on: your eye, telescope, camera film, digital camera
fg 4 p. 327
concave _________mirror
object is placed ________the principal focus of a concave mirror  _________, upright, farther from the mirror then the
object, __________image
Using Convex Mirrors
Curved surface _________light from all parts of a room or area into your eye  large ______of
view
Ex: fg 5a p. 327
Ex: ___________mirrors
Ex: car _________mirrors fg 6 p. 327
 ______, smaller, ________away images
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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summary:
Image Characteristics of Different Mirrors
p. 328 Demonstrate with giant concave mirrors
PLANE MIRROR
CONCAVE
MIRROR (object is
closer to the mirror
than the principal
focus) fg 4 p. 327
CONCAVE
MIRROR (object is
farther from the
mirror then the
principal focus) fg 1
p. 326
Larger than the
object but becomes
smaller as object
distance increases
Inverted
CONVEX MIRROR
SIZE
Same size as object
Larger than object
ATTITUDE
Upright
Upright
LOCATION
Behind mirror
Same distance from
mirror as object
Behind mirror
Farther from the
mirror than the object
In front of mirror
Distance varies
depending on distance
of object
Behind mirror
Farther from the
mirror than the object
TYPE OF IMAGE
virtual
Virtual
real
Virtual
Smaller than object
Upright
HW: cyu 11.6, 11.6
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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Sec. 11.7
p. 329
The Refraction of Light
http://www.wonderhowto.com/how-to-make-coins-disappear-with-light-refraction-magic-trick-222281/
Refraction: The bending of light as it passes from one medium (substance) to another
medium
http://www.youtube.com/watch?v=6JqFdkjGkEI&feature=related
ex: fg 1 light bends as it moves from one medium to another: water into air 
distorted image
http://www.youtube.com/watch?v=uoN4qg2hHQo&NR=1&feature=fvwp
http://science.discovery.com/videos/head-rush-disappearing-glass.html
Terms: fg 2 p. 329
incident ray: incomming light ray
normal: imaginary line that is 90° (perpendicular) to
the refracting surface
refracted ray: the ray of light that has changed direction
(bent) as it passed from 1 medium (material) to another
(different materials have different densities)
angle of incidence: angle between the incident ray and
the normal
angle of refraction: angle between the refracted ray
and the normal
Sec. 11.8
Refracting Light in Lenses
p. 331
lens: curved, transparent device that refracts (bends) light
ex: fg 1
light reflects off pepper  travels through lens  refracts (magnifies)  eyes
other examples: eyeglasses, contact lenses, camera lenses
Why? Speed of light differs in different
materials (densities)
change of speed produces a change of
direction (refraction)
fg 2 p. 331
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/raydiag.html
Designs of Lenses: (2 types) p. 332
1) convex: thick in middle, thin on outside
fg 3 p. 332
principal focus: the position where parallel
light rays come together
focal length: distance from the principal focus
to the center of the lens
light rays converge (come together)
2) concave: fg4 p. 333
-principal focus: the position where parallel rays
appear to come from
-light rays diverge (spread apart)
Sec. 11.7
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
p. 329
The ______________of Light
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Refraction: The ___________of light as it passes from one ___________(substance) to
another medium
ex: fg 1 light ______________as it moves from one medium to another: water into
air  ___________image
Terms: fg 2 p. 329
__________ ray:
incomming light ray
normal: ___________line that is 90° (perpendicular) to
the ____________surface
___________ray: the ray of light that has changed
direction (_____________) as it passed from 1 medium
(material) to another (different materials have different
densities)
___of incidence: angle between the __________ray and
normal
the
angle of ___________: angle between the ________ray
and the normal
Sec. 11.8
Refracting Light in ___________
p. 331
lens: ____________, transparent device that refracts (bends) light
ex: fg 1
light reflects off pepper  travels through lens  refracts (______________)  eyes
other examples: eyeglasses, ___________lenses, __________lenses
Why?________of light differs in ___________
materials (densities)
_________of speed produces a change of
direction (____________)
fg 2 p. 331
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/raydiag.html
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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Designs of Lenses: (2 types) p. 332
1) __________: thick in middle, thin on
outside
fg 3 p. 332
principal ___________: the position where
_________light rays come _________
focal _________: distance from the principal
focus to the _______________of the lens
light rays ___________(come together)
2) ____________: fg4 p. 333
-__________focus: the position where parallel rays
___________to come from
-light rays _____________(spread apart)
E:\New school folder sept\new Science 8 probe\ch 11 mirrors and Lenses\notes\2011 Ch 11 notes.docx
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