Science 8 Name: ______

Quiz Review Vision, Refraction and Reflection

1.  Write the names for the parts of the eye next to the correct letter in the table.

a
b
c
d
e
f
g

2.  Write the names for the parts of the eye next to the correct definition in the table.

“hole” in the iris where light enters
area where image forms and is made into a nerve signal
helps focus light onto the retina
carries nerve signals to the brain
controls the thickness of the lens (to focus)
outer layer that helps focus light onto the retina
makes the pupil larger or smaller (where your eye colour is located

3.  Answer each question in complete sentences.

a.  How do your iris and pupil control the amount of light entering the eye?

b.  Why does your pupil appear black?

c.  Where does refraction occur in the eye?

d.  How do your ciliary muscles and the lens help you focus on near and far objects?

e.  What are the two special types of cells in your retina that detect light?

f.  How are the two types of cells different? (What does each do?)

Describing Images Page 276

1.  Why is your eye an optical device?

2.  What is a real image?

3.  What is a virtual image?

4.  Complete the table to show how the letters SALT to help you remember the four characteristics of images.

Characteristic / Possible Descriptions
S
A
L
T

5.  If describe the characteristics of size, attitude and type for the image below.

Class notes on Refraction

6.  Does light slow down or speed up in a dense medium?

7.  When light slows down it bends ______the normal line. (toward or away?)

8.  When light speeds up it bends ______from the normal line. (toward or away?)

9.  Complete the following ray diagrams by showing estimated changes to the refracted ray (Toward or away from the normal line, by a lot or a little?) Use a ruler!

Air Water Diamond Air

normal line normal line

Refracting Light in Lenses P. 290 (plus hands on: Exploring Lenses)

10.  Which lenses are thin in the middle, and which lenses are thick in the middle?

11.  When you use a convex lens to look at a nearby object, is the image smaller or larger, upright or inverted?

12.  When you use a convex lens to look at a far object, is the image smaller or larger, upright or inverted?

13.  When you use a concave lens to look at a nearby object, is the image smaller or larger, upright or inverted?

14.  When you use a concave lens to look at a nearby object, is the image smaller or larger, upright or inverted?

15.  Which lens can produce a real image?

16.  Use dashed lines to draw the path of the rays of light entering each lens

A Telescope for every Wave Page 300

17.  What is the difference between a reflecting and a refracting telescope?

18.  What are two problems related to using lenses in telescopes?

Getting in Light’s Way (Page 274-275)

19.  What happens to light energy that is absorbed by a surface?

20.  What surface colours will absorb the most light?

21.  What surface sheen (shininess) will absorb the most light?

22.  What surface texture will absorb the most light?

Class notes and Using Curved Mirrors Page 286

23.  What is the difference between specular and diffuse reflection?

24.  What are the two laws of reflection?

25.  Draw a diagram (use a pencil, protractor and ruler) showing the first law of reflection.

26.  Which type of curved mirror creates an image that is ALWAYS virtual and upright?

27.  Which type of curved mirror creates an image that is sometimes virtual and upright and sometimes real and inverted (depending on the distance of the object)?

28.  What are two practical uses of convex mirrors?

29.  What are three practical uses of concave mirrors?

30.  Why do drivers have to be careful in using convex mirrors while backing up?

31.  (Think) Why are concave mirrors so helpful as solar collectors?