1. Refraction
By: Savannah and Trent

2. Objectives
• Recognize situations where refraction will
occur.
• Identify which direction light will bend
when it passes from one medium to
another.

3. Introduction
• In this presentation we will discuss the
refraction of light and the situations in
which it occurs and why it happens.
• We will also discuss how refraction travels
through different mediums and how the
light bends.

4. Discovery of Refraction
• Willebrord van Roijen Snell discovered
refraction in the early 1600’s.
• However refraction only became known
everywhere when Christian Huygens
published Snell’s and his own results in
“Dioptrica” and got the information out.

5. What is Refraction?
• When light passes from one medium into
a second medium, the light path bends.
• If a substance causes the light to speed
up or slow down more, it will refract more.

6. Why Does Refraction Occur?
• Refraction occurs when it is at the
boundary of a medium and it caused by
the change in speed.
• Light refracts because it travels at an
angle into a substance with a different
refractive index.

7. Determining Direction
• FST= Fast to Slow, Towards the normal
• FSA= Slow to Fast, Away from the normal

8. Examples

9. Examples

10. What is the Refractive Index?
• It’s the ratio of velocity of light in two
media and hence it is a number without a
unit.
• The ratio of the speed of light in a vacuum
to the speed of light in a medium is called
the refractive index of the medium

11. Angle of Incidence
• The angle which the incident ray makes
with the normal ray at the point of
incidence.
• The angle of incidence is basicly the
angle between the incident ray and the
normal.

12. Angle of Refraction
•
Its the angle that the refracted ray makes
with the normal line

13. Angles

14. What is a Lens?
• It’s a part of a transparent refracting
medium bounded by two spherical
surfaces or one curved and one plane
surface.
•
Two types: Biconvex and biconcave.

15. Biconvex Lens
• It’s thicker at the middle than it is at the
edges.
• Parallel rays of light can be focused into a
focal point.
•
This is the kind of lens used for a
magnifying glass.

16. Biconcave Lens
• Is thinner at the middle than it is at the
edges.
• Light rays refract outwards and spread
apart as they enter the lens and again as
they leave.

18. Bibliography
•
•
•
Henderson, Tom. "The Cause of Refraction." The
Cause of Refraction. Tom Henederson, 2013. Web. 25
Oct. 2013.
Serway, Raymond A., and Jerry S. Faughn. "Refraction
." Holt physics. Austin, Tex.: Holt, Rinehart and
Winston, 2002. 487-492. Print.
Zobel, Edward . "Ray Optics, Light Refraction." Light
Refraction. N.p., n.d. Web. 25 Oct. 2013.
<http://zonalandeducation.com/mstm/physics/light/rayO
ptics/refraction/refraction1.html>.