Name: Emmalia Miller Date: 5/1/18

Student Exploration: Refraction

Vocabulary: angle of incidence, angle of refraction, frequency, index of refraction, medium,

refraction, Snell’s law, total internal reflection, wave front, wavelength, wave speed

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

Two runners ran side by side, each holding one end of a horizontal pole.

1. What would most likely happen if one of the runners began jogging in knee-deep water?

The jogger who was running in the water probably slow down.

How would this affect the direction of the runners? Explain. This would affect the

direction of the runner because the runner would try to run forward, but the runner would

end up slipping and most likely falling backwards.

2.

Gizmo Warm-up

Light can travel through many materials, or media. As with a

runner on pavement or sand, the speed of light can change

when it moves into a different medium. The Refraction

Gizmo™ allows you to observe what happens to a beam of

light as it travels from one medium to another.

Turn off View wave fronts. Set Index of refraction 2 to 3.0.

1. Click Play ( ). Observe the ray of light as it passes from Medium 1 to Medium 2.

A. What happens to the speed of the light wave? The speed of the light wave stayed

the same

B. What happens to the direction of the light wave? The direction of the light turned to a

90 degree angle.

The bending of the light ray you see is called refraction.

2. Click Reset ( ) and turn on View wave fronts. A wave front is an imaginary line that

connects the crests or troughs of a wave. The wavelength of a wave is the distance

between wave fronts.

Click Play. What happens to the wavelength of the wave as it passes into Medium 2?

The wavelength still changed into a 90 degree angle

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Activity A:

Angle of

refraction

Get the Gizmo ready:

 Click Reset. Turn off View wave fronts.

 Make sure View normal is selected.

 Make sure Index of refraction 1 is 1.0 and Angle

of incidence is 45°.

 Set Index of refraction 2 to 2.0.

Introduction: The normal is an imaginary line perpendicular to the boundary between two

media. The angle of incidence is the angle between the light ray in medium 1 and the normal.

The angle of refraction is the angle between the ray in medium 2 and the normal.

Question: What affects how much light waves refract?

1. Measure: Click Play. To measure the angle of refraction, turn on Click to

measure angles. Drag the protractor’s vertex to the intersection of the

ray and the normal. Align the protractor’s legs to the ray and the normal in

Medium 2.

What is the angle of refraction? 20.12

2. Gather data: For each angle of incidence listed in the table below, use the Gizmo to find the

angle of refraction. Then, fill in the “Change of direction” column by subtracting the angle of

refraction from the angle of incidence.

Angle of incidence Angle of refraction Change in direction

20° 9.33 10.7

40° 18.19 21.8

60° 24.61 35.4

80° 29.09 50.4

3. Analyze: What patterns do you notice? That the angle of refraction is nearly half of what the

angle of incidence is.

4. Explain: Do you think refraction would occur if the angle of incidence is 0°? Explain.

No because there wouldn’t be a change in direction, which means that there would be an angle

of refraction

(Activity A continued on next page)

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