This document discusses optical phenomena caused by the interaction of light with different materials and atmospheric conditions. It explains that refraction occurs when light passes from one medium to another with a different density, which causes the bending of light. Total internal reflection takes place when light hits the boundary between two mediums at an angle greater than the critical angle, and this phenomenon is used in fiber optics to transmit light along the length of the fiber. Dispersion is the separation of white light into visible colors due to different wavelengths bending at different angles when refracted. Rainbows are caused by the refraction and dispersion of white light when it passes through water droplets in the atmosphere.

1. Optical Phenomena
By:
Lindsay Gunter & Megan Oliver

2. Objectives
• Recognize atmospheric conditions that
cause refraction.
• Explain dispersion and phenomena such
•
as rainbows in terms of the relationship
between the index of refraction and the
wavelength.
Demonstrate internal reflection with
fiber optics.

3. Introduction
• In this lesson, we will be looking at what
causes refraction.
• We will also be learning about how
phenomena occur due to the interaction
between light and matter.

4. What causes refraction?
• Changes in:
o temperature
o pressure
o moisture
o medium
Refraction happens when there is a
change in density.

5. What does light do when
it is refracted at
different angles?

6. Critical Angle
• The angle that causes the refracted light
rays to move parallel to the boundary at
a 90o angle to the normal.

7. Angles greater than the
critical angle will be totally
internally reflected.

8. Total Internal Reflection
• When light moves along a path inside of
a medium.

9. Fiber Optics
• When light is internally reflected until it
reaches the end.

10. Light (Sun) Pillars
• When the light
reflects off of ice
crystals in the sky.
• You may get pillars
of light in yellows,
blues, reds, and violet colors.

11. Ice Halo
• Happens when the Sun or Moon refracts
in the ice crystals in the clouds.
• Sometimes the light isn’t refracted by its
wavelength, which causes a white color
halo. Other times,
it creates a rainbow
of reflected color.

12. Mirage
•
•
A mirage occurs when the ground heats the
air above making it hotter than the air at
higher altitudes.
This results in you seeing
the upright image and the
inverted image, which
appears to you as a reflection in water.

13. Dispersion
• The bending of light at different angles
due to each wavelengths’ index of
refraction.
• Longer wavelengths=
less refraction
• Shorter wavelengths=
more refraction

14. Rainbows
•Occur when white light is refracted in
water droplets.
•This causes the
distinct colors of
the rainbow.

15. Review Questions
1. What changes in the atmosphere could
cause refraction?
2. What happens when an angle is totally
internally reflected?
3. What is one phenomena that is caused by
total internal reflection?
4. How does a mirage occur?
5. In dispersion what causes the light to
bend at different angles?

16. Bibliography
•
•
•
•
•
•
LIGHT PILLAR PICTURES: Mysterious Sky Shows Explained. (n.d.).
National Geographic. Retrieved October 29, 2013, from
http://news.nationalgeographic.com/news/2009/02/photogalleries/lig
ht-pillars/
halo. (2013). In Encyclopædia Britannica. Retrieved from
http://www.britannica.com/EBchecked/topic/252957/halo
Serway, R. A., & Faughn, J. S. (2009). Physics. Austin: Holt.
Crowley, L. (n.d.). Atmospheric Optics. Atmospheric Optics. Retrieved
October 29, 2013, from http://www.atoptics.co.uk/
Internal Reflection. (n.d.). Tutor Dynamic. Retrieved October 29,
2013, from http://www.tutordynamic.com/physics/internalreflection.htm
Deprest, M. S. (n.d.). Atmospheric Optical Phenomena.. Atmospheric
Optical Phenomena.. Retrieved October 29, 2013, from
http://www.umich.edu/~lowbrows/reflections/2009/mdeprest.35.htm
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