SCIENCE 8
CHAPTER 11 MIRRORS AND LENSES
I don’t know what I may seem to the world, but as to myself, I seem to have been only like a
boy playing on the sea--‐shore and diverting myself in now and then finding a smoother pebble
or a prettier shell than ordinary, whilst the great ocean of truth lay undiscovered all before
me.’
Sir Isaac Newton
To get started:
1. Read the chapter over on your own.
2. 2. Go to pages 336 to 337 and begin to learn all of the vocabulary words. You must make
either a vocabulary sheet in the Cornell notes style or a set of flashcards.
11.1 INQUIRY INVESTIGATION: REFLECTING LIGHT OFF
A PLANE MIRROR
I. a __________________ is a flat, 2-dimensional surface
II. an ____________________________ is a ray of light that travels
towards a reflecting surface
III. The _______________________________ is the spot where the
incident ray strikes the reflecting surface
A. It is not labelled on the diagram that you are given so we will label
it together.
IV. the ___________________ is the line drawn from the the point of
incidence at 90º to the surface of the optical device
V. the _______________________________ is the angle between the
incident ray and the normal
VI. a ________________________________ is a ray of light that
bounces off a reflecting surface
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II. _________________________________ is the angle between the
reflected ray and the normal
VIII. The ________________________________ is equal to the angle
of reflection
Figure 1. Light reflection from a plane mirror.
http://laser.physics.sunysb.edu/~amy/wise2000/websites/Mirror348.jpg
11.2 REFLECTING LIGHT OFF SURFACES
I. Specular Reflection
A. ____________________ reflection is the reflection of light off a
smooth, shiny surface
1. When this happens an __________________ is created
2. Occurs off __________________, shiny __________________
and the surface of still ___________________
Figure 2. Specular and Diffuse Reflection.
http://www.mysciencesite.com/optics3.html
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II. The Laws of Reflection
A. __________ represent light as it travels
B. _____________ are used to summarize the results of an experiment
if the results are ________________________
C. There are 2 laws of reflection
1. the angle of incidence always __________________ the angle of
reflection
2. the incident ray, normal, and reflected ray all lie in the same
______________________
Here is a website with an activity to illustrate these two laws.
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/reflection/index.html
D. The laws of __________________________ help us to understand
why the eye sees an ___________________ in a plane mirror
1. the image appears to be ______________ the mirror
2. the ____________________ rays seem to come from the
image that is __________________ the mirror
a. Extending the ________________ rays behind the mirror
shows this
b. Each set of _________________________ and
_________________________ rays follows the first law of
reflection (C1)
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Figure 3. How an image is formed using a plane mirror.
http://image.tutorvista.com/content/light-reflection/plane-mirror-image-formation.gif
III. Diffuse Reflection
A. __________________ reflection is when light is reflected off an
_________________ or ________________ surface
1. The light is ____________________ in many directions
2. No _____________________ is formed
B. ________________ light from a source and ________________
light from a regular or smooth surface can _________________
the eyes
1. a room with a ___________________ light source and many
____________________ would be very hard on the eyes
2. _____________________ light is easier on the eyes
a. Ceilings are often coated with an __________________
surface to cause diffuse light reflection
b. __________________ light bulbs diffuse light
c. _______________________ also diffuse light
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Now answer 11.2 Check Your Understanding #2-4 on p. 318.
11.3 DESCRIBING IMAGES
I. an ______________ is the likeness of an object
II. an _______________________ produces an image of an object
III. Real and Virtual
A. A __________ image can be placed on a screen
B. A __________ image cannot be placed on a screen
1. can only be seen by looking at or through an
_______________________________________ such as the
following: ____________________________,
*Please see Table 1 at the end of these notes for a summary.
Now answer 11.3 Check Your Understanding #1 on p. 320.
11.4 INQUIRY INVESTIGATION: VIEWING IMAGES IN A PLANE
MIRROR
11.5 INQUIRY INVESTIGATION: CURVED MIRRORS
Here is a quick example of what concave and convex mirrors can do and an
activity to practice their effects:
http://www.learner.org/teacherslab/science/light/lawslight/funhouse/index.html
I. a convex mirror has the reflecting surface on the _______________
curve
A. Convex mirrors make the image ___________________ than the
object
B. Like the back of a ______________
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C. i.e. On the _______________
D. e.g. The mirror in a ________________________ that is used
to watch for shoplifters, seeing around _________________ in
parking lots, _______________ mirrors and _______________
mirrors (this is why objects in mirror are closer than they
appear)
II. a concave mirror has the reflecting surface on the _______________
curve
A. Concave mirrors make the image _________________ than the
object
B. Like the ________________ of a spoon
C. i.e. In the dip/dent
D. e.g. The mirror in a ______________ lamp, car _____________,
makeup/_________________ mirrors, _______________, solar
furnaces
11.6 USING CURVED MIRRORS
First read and complete pp. 74-75 in the BC Science 8 workbook.
I. Terms That Are Used to Describe Concave Mirrors
A. ____________________ is a line through the centre of the
mirror that includes the principal focus
B. _____________________________ is the position where the
reflected parallel light rays come together
C. _______________ is the distance from the principal focus to the
middle of the mirror (often represented with the letter ______ as
in the diagram below)
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Figure 4. The concave mirror.
http://gcserevision101.wordpress.com/physics-p3/
D. When the object is beyond the focus, the image is _____________
and can only be placed on a screen
Figure 5. A concave mirror with the object beyond the focus.
http://home.roadrunner.com/~enloephysics/mirror1.gif
E. When the object is between the focus and the mirror, the image is
_______________ e.g. A cosmetics mirror
Figure 6. A concave mirror with the object closer than the focus.
http://home.roadrunner.com/~enloephysics/mirror2.gif
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II. Terms That Are Used to Describe Convex Mirrors
A. _________________________ is a line through the centre of the
mirror that includes the principal focus
B. ______________________________ is the position where parallel
light rays appear to reflect from (labelled ___ on the diagram below)
C. ____________________ is the distance from the principal focus to
the middle of the mirror (the distance between V and F on the diagram
below)
Figure 7. A convex mirror.
http://img.sparknotes.com/content/testprep/bookimgs/sat2/physics/0004/convexmirrorraytracing.gif
Figure 8. The image formed using a convex mirror.
http://home.roadrunner.com/~enloephysics/mirror3.gif
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III. Using Concave Mirrors
A. _____________________________________ make images that
can be viewed, photographed or digitally recorded (page 326)
Figure 9. How a reflecting telescope works.
http://astrocanada.ca/_en/_illustrations/a4304_newton_en_p.jpg
IV. Using Convex Mirrors
A. Used in the large ____________________ mirrors in many stores
B. Images are always _______________ and _______________
than the object no matter where the object is located
C. Gives the observer a _______________ field of view than does a
plane mirror
Figure 10. A comparison of concave and convex mirrors.
http://micro.magnet.fsu.edu/optics/lightandcolor/images/reflectionfigure4.jpg
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Now complete pp. 76-79 in the BC Science 8 workbook. Then answer
11.5 Check Your Understanding # 1-6.
11.7 Inquiry Investigation: The Refraction of Light
I. ____________________: the bending of light as it travels from
one material to another
II. _______________________: the ray of light that changes
direction as it passes from one material into another
III. ___________________________: the angle between the
incident ray and the normal
Figure 11. The refraction of light from air to water.
http://misclab.umeoce.maine.edu/boss/classes/SMS_491_2003/refraction.gif
11.8 Refracting Light in Lenses
First read and complete pp. 80-81 in the BC Science 8 workbook.
I. ____________: curved transparent device that causes light to refract
as it passes through
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A. Examples of lenses include: ______________________,
____________________, ______________________,
______________________________
II. Why Does Light Refract?
A. Light changes ___________________ when it travels through
different transparent materials
1. this causes the light to change ___________________
III. Designs of Lenses
A. Lenses are usually _________________ or __________________
1. a concave lens is ________________ in the middle than at the
outer edges
2. a convex lens is ________________ in the middle than at the
outer edges
3. a light ray that travels through the _______________ of
the lens is not _________________ because it meets
the lens at a ________angle
B. Terms to describe lenses and their images
1. _________________________: the position where parallel light
rays appear to come from
2. _____________________: the distance from the principal
focus to the centre of the lens
3. ______________________: a line through the centre of the lens
that includes the principal focus
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Figure 12. The convex lens.
http://media-2.web.britannica.com/eb-media/27/4627-004-E3B847C3.gif
Figure 13. The concave lens.
http://www.antonine-education.co.uk/physics_a2/options/Module_6/Topic_2/ray_diag_7.gif
IV. Combining Lenses
A. Devices that combine more than one lens include
________________________, _______________________, and
________________________
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Now complete pp. 82-85 in the BC Science 8 workbook. Then answer
11.8 Check Your Understanding #3-7.
Table 1: Characteristics of Images (slightly modified from p. 320)
Characteristic
Possible descriptions
1. ____________ than the object being viewed
Size
2. ____________ than the object being viewed
3. the _______ size as the object being viewed
Attitude
1. ____________________ (right-side up)
2. ____________________ (upside-down)
1. refers to the __________________ of the
image from the optical device
a. Could use the distance of the
Location
______________ from the optical device for
comparison
2. variable
e.g. On the side of the lens opposite the object
e.g. Closer to the optical device than to the object
1. __________ (can be placed on a screen)
Type
2. __________ (cannot be placed on a screen but
can only be seen by looking at or through an optical
device)
To review the whole chapter:
1. Make sure that your vocabulary reinforcement is complete.
2. Answer the following questions on pp. 338-339: #1-5, 7, and 8.
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