1. Light is bent when passing from one medium to another due to refraction. Water was placed on a DVD disc and the bending of light was observed as it passed into the water. 2. The speed of light decreases in denser mediums like water compared to air. Different materials have different refractive indices that determine how much light bends when passing into them. 3. When viewing an object underwater, the light rays bend more upon exiting the water, making the object appear higher or closer than its actual position, creating a depth illusion.

4. A DVD disc and a
bottle of water have
been provided to you.
Place some water on
the disc and observe.

6. The light beam is bent:
• between the air and the liquid;
• between the liquid and the glass.
As the light crosses the boundary
between two different mediums, it
is bent, producing a distorted
image.
The bending of light is called
refraction.

7. A material which light passes through, such as glass or air, is known as a
medium.
When light passes through air, it travels at about 300,000,000 m/s (about
the same as it does in a vacuum).

9. Medium Refractive Index, n Speed of light, v (m s-1)
Air 1.00 3 x 108 = c
Water 1.33 2.26 x 108
Diamond 2.42 1.24 x 108

10. When the car moves into
a different road surface, it
changes speed as it enters
from the road to the
sand.
Here, the car’s right
wheel will slow down first
as it hits the sand, causing
the car to veer right.

11. In this situation, when the car is
driven at a right angle, the car will
not change its angle.
However, the speed of the car
changes because the nature of the
road surface determines the
speed.

12. The incident ray (i°) and refracted ray (r°) are on the
opposite sides of the normal at the point of incidence, and
all three lie on the same plane.
i°
r°
Normal line
Point of incidence

13. The mediums involved in the law of refraction will only be
air/water or air/another medium.
i°
r°
Normal line
Point of incidence

14. normal
air
glass
incident
ray
refracted ray
angle of incidence
angle of refraction
The ray of light is refracted or bent
towards the normal from the air into the
glass.
Note that the angle of refraction, r is
smaller than the angle of incidence, i.
r < i
This means that glass is more dense than
air.
Light is bent towards the normal when it
enters a medium of a higher refractive
index.

15. normalair
glass
incident
ray
refracted ray
angle of incidence
angle of refraction
The ray of light is refracted or bent away
from the normal from the air into the
glass.
Note that the angle of refraction, r is
larger than the angle of incidence, i.
r > i
This means that air is less dense than air.
Light is bent away from the normal when
it enters a medium of a lower refractive
index.

16. In the diagram below, label the following terms:
a) ray of incidence
b) ray of refraction
c) angle of incidence
d) angle of refraction
What can you conclude about the mediums?

17. In the diagram below, label the following terms:
a) ray of incidence
b) ray of refraction
c) angle of incidence
d) angle of refraction
What can you conclude about the mediums?
b
c
a
d
The glass medium is more dense than the
air medium.
Glass has a higher index of refraction than
air.

18. Sketch a ray diagram for the following angles.
i = 30°
r = 65°
i = 90°
r = 90°

19. i = 30°
r = 65°
i = 90°
r = 90°
Sketch a ray diagram for the following angles.
30°
65°
All angles are draw from the normal.

20. The chest appears to be at a shallower water than its original
position. This causes a depth illusion to the viewer on the boat.
Light reflected off
the chest is bent
away from the
normal from water
to air.

21. When you look at the refracted light, your retina processes the
light in a straight line.
Hence, this makes
the chest appear to
be closer to the
water.