Lab 6
Refraction of Light
Objectives:
• Verify Snell’s Law and use it to identify an unknown material.
• Determine how intensity changes when light is refracted.
Background: How does light bend?
Light travels at different speeds in different media. As light passes at an
angle from one medium to another, it changes direction at the boundary
between the two media. The index of refraction of a medium, n, is the
ratio of the speed of light in a vacuum, c, to its speed in the substance, v.
c
n= v
When light enters a medium with a higher index of refraction than the
medium it is leaving, it bends toward normal. When light enters a
medium with a lower index of refraction than the medium it is leaving, it
bends away from the normal. This change of direction of light at the
boundary of two media is called refraction. For any light that is traveling
from one medium of index of refraction n1, at angle of incidence θ1, to
another medium of index of refraction n2, Snell’s law of refraction
describes the angle of refraction, θ2, experienced by the light.
n1 sin θ1=n2 sin θ2
In this lab, you confirm Snell’s Law by taking simple measurements. You
will also investigate what happens to the intensity of the light as it
refracts, and you will determine the refractive index of two unknown
materials.
For this lab, you are required to submit a short lab report, containing the
answers to all questions in Parts One, Two and Three. Your submission
simply needs to contain the answers, data tables, graphs and
sketches, like how you submit the assignments. You may handwrite
your answers and take photos of your work, or you may use Word,
Google Docs etc...
You must submit a single pdf document on Canvas under
‘Assignments -> Lab 2: Refraction’.
1
, For this lab you will be using an online simulator from the University of
Colorado Boulder. Click on the link below to get to the website:
https://phet.colorado.edu/en/simulation/bending- light
Once you get there, click on ‘Intro’.
Part 1: Confirming Snell’s Law
a) When the simulator window opens, you should notice a laser
pointing at a 45o angle downwards to the right. Look to the
right of the window and notice that the two information boxes are
explaining the mediums that are shown on the screen.
What are the two mediums on the simulator window
currently? The two mediums are air (1.00) and water
(1.33)
b) Click on the RED button on the laser. What two things does the light
do as it hits the surface of the water?
Light is partially reflected back into the air and also refracted back into
the water.
c) Change the material of the second medium (where the refracted
ray is) to Glass using the menu box on the bottom right.
Choose the protractor tool and place the protractor over the vertical
normal line
2
Refraction of Light
Objectives:
• Verify Snell’s Law and use it to identify an unknown material.
• Determine how intensity changes when light is refracted.
Background: How does light bend?
Light travels at different speeds in different media. As light passes at an
angle from one medium to another, it changes direction at the boundary
between the two media. The index of refraction of a medium, n, is the
ratio of the speed of light in a vacuum, c, to its speed in the substance, v.
c
n= v
When light enters a medium with a higher index of refraction than the
medium it is leaving, it bends toward normal. When light enters a
medium with a lower index of refraction than the medium it is leaving, it
bends away from the normal. This change of direction of light at the
boundary of two media is called refraction. For any light that is traveling
from one medium of index of refraction n1, at angle of incidence θ1, to
another medium of index of refraction n2, Snell’s law of refraction
describes the angle of refraction, θ2, experienced by the light.
n1 sin θ1=n2 sin θ2
In this lab, you confirm Snell’s Law by taking simple measurements. You
will also investigate what happens to the intensity of the light as it
refracts, and you will determine the refractive index of two unknown
materials.
For this lab, you are required to submit a short lab report, containing the
answers to all questions in Parts One, Two and Three. Your submission
simply needs to contain the answers, data tables, graphs and
sketches, like how you submit the assignments. You may handwrite
your answers and take photos of your work, or you may use Word,
Google Docs etc...
You must submit a single pdf document on Canvas under
‘Assignments -> Lab 2: Refraction’.
1
, For this lab you will be using an online simulator from the University of
Colorado Boulder. Click on the link below to get to the website:
https://phet.colorado.edu/en/simulation/bending- light
Once you get there, click on ‘Intro’.
Part 1: Confirming Snell’s Law
a) When the simulator window opens, you should notice a laser
pointing at a 45o angle downwards to the right. Look to the
right of the window and notice that the two information boxes are
explaining the mediums that are shown on the screen.
What are the two mediums on the simulator window
currently? The two mediums are air (1.00) and water
(1.33)
b) Click on the RED button on the laser. What two things does the light
do as it hits the surface of the water?
Light is partially reflected back into the air and also refracted back into
the water.
c) Change the material of the second medium (where the refracted
ray is) to Glass using the menu box on the bottom right.
Choose the protractor tool and place the protractor over the vertical
normal line
2
