Bending Light PhET Simulation Summary

Open the "Bending Light PhET Simulation". Select the 'Intro' setting. Engage with the simulation and take mental notes of what you observe. Make sure to choose different materials, indices of refraction, rays/waves, and to try the 'Prisms' setting.

Reset the simulation and recreate the picture below. You should see a red ray from the laser that strikes the boundary between the two different materials. The segment of the ray, from the laser to the boundary, is called the incident ray. The part that bounces off the boundary is the reflected ray. The part that passes through the boundary is called the refracted ray. The angles of each ray are measured from the zero line.

1. Label all three rays

1. Measure and record all three ray angles
   1. Incident angle: ____________
   2. Reflected angle: ____________
   3. Refracted angle: __________

1. What do you notice about the reflected ray compared to the incident ray? What do you notice about the refracted ray compared to the incident ray? List at least 5 similarities or differences.

1. Hypothesize why this is the case:

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1. Record the angle of reflection for several angles of incidence

Incident Angle I	30	45	55	65
Reflection Angle r

1. What can you conclude from this data? *CHECKPOINT ________

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1. Notice the light changes direction. What do you think causes this?

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Select the 'More Tools' setting and click on the yellow "Reset All". Press the red button to turn on the laser. Click on the Wave setting in the top left corner. Drag the "Speed" tool from the toolbox, placing its point on theincident ray ONLY.

1. What does 1.00 c mean if 1.00 means 100% and c means the speed of light.?

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1. Predict (without checking) what the speed of the reflected ray will be: faster equal slower

1. Predict (without checking) what the speed of the refracted ray will be: faster equal slower

1. Move the speed tool to the reflected and refracted ray. Measure and record the speed

Reflected Ray Speed: _____________ Refracted Ray Speed: _____________

1. Compare the speed of the reflected and refracted ray to the speed of the incident ray.

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1. Hypothesize why the this is the case:

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1. Record the speed of light in material 2 (lower medium) for the listed indices of refraction.

Index of Refraction (n) in Material 2 (lower medium)	1.00	1.25	1.33	1.5
Speed of light (c) in Material 2 (lower medium)

1. What can you conclude from this data?

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*CHECKPOINT ________

Change the second material to match the listed index of refraction.

1. Record the speed of light in Material 2 based on the listed speed of light in Material 1. Then list the ratio of A:B as a decimal (A = Speed of Light in Medium 1 (top medium), B = Speed of Light in Medium 2 (lower medium))

Index of Refraction (n) in Material 2 (lower medium)	1.00	1.25	1.33	1.5
Speed of light (c1) in Material 1 (top medium)	1.00c	1.00c	1.00c	1.00c
Speed of light (c2) in Material 2 (lower medium)
The ratio of A to B represented as a decimal
The ratio of A to B represented as a fraction

1. Compare the value of the index of refraction in material 2 to the ratio of A to B.

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1. Based on the data, generate an equation to calculate the index of refraction (n) based on the speed of light in material 1 (c₁) and the speed of light in material 2 (c₂).

1. If a student proposed the general rule. "The speed of light is constant.", would you agree or disagree and why? Explain your response using evidence from your data.

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Select the 'More Tools' setting at the bottom of the simulation, press the red button to shine a beam, then set the light beam to the 'Wave' setting. Use the blue tool to observe the frequency of different rays using the dark and light gray magnifying glasses. Slide the color setting to go from violet to red.

1. What do you observe happens to the wavelength shown in the window above the color scale?

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1. What do you observe happens to the frequency shown in the window of the blue tool?

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1. What type of relationship exists between wavelength and frequency? Linear Horizontal Inverse Quadratic

Select the 'Prism' setting at the bottom of the simulation. Choose the triangular prism and multiple rays.

1. What do you notice happens to the angle as you go from red to violet?

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1. Based on your previous response, what other factor(s) is refraction dependent on?

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1. Hypothesize how a rainbow may be formed.

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1. Why does light bend more in glass than in water?

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1. Hypothesize what the termIndex of Refraction means.

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1. What happens to the brightness of the reflected light? (circle one) brighter dimmer stays the same disappears

1. What happens to the brightness of the refracted light? (circle one) brighter dimmer stays the same disappears

1. Hypothesize why:

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1. Describe the relationship between the speed of light and the index of refraction.

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Use the word bank below to fill in the blanks appropriately

Increases Index of Refraction Refraction Transmission

Reflection Decreases Incident Intensity

1. ________________ is when light bends due to a change in medium.

1. ________________ is when light passes through a boundary due to a change in medium.

1. ________________ is when light bounces off a boundary due to a change in medium.

1. The _________________________ determines how light will bend when moving into a new medium.

1. The ____________________ ray determines the angle of reflection and refraction

1. The ______________________ represents the brightness of a light, representing it's amplitude.

1. The speed of light ______________ when we move into a medium with a higher index of refraction.

1. The speed of light ______________ when we move into a medium with a lower index of refraction.