Refraction & Total Internal Reflection Worksheet
Goal: Use Snell’s law, n₁ sin θ₁ = n₂ sin θ₂, to predict how light bends between materials, and find the critical angle for total internal reflection.
What to do
- Press Reset, then “Air → glass” (n₁ = 1, n₂ = 1.5, 35°). Record the refracted angle, critical angle and behavior.
- Press “Glass → air” and record. Then press “Internal reflection” (60°) and record.
- Still going from glass to air, set the Incident angle to 41°, then to 42°. Record both rows.
- Press “Air → glass”, then set the second medium n₂ to 1.33 (water). Record the last row.
Record your results
| Setting | Refracted angle | Critical angle | Behavior |
|---|---|---|---|
| Air → glass at 35° | |||
| Glass → air at 35° | |||
| Glass → air at 60° | |||
| Glass → air at 41° | |||
| Glass → air at 42° | |||
| Air → water at 35° |
Questions
Going from air into glass, did the light bend toward or away from the normal? Why?
Going from glass to air at 35°, what is the refracted angle? Why is it larger than 35°?
What happened at 60° going from glass to air? Use the critical angle to explain.
Compare 41° and 42°. What happens to the refracted ray as you approach the critical angle?
Light enters water (n = 1.33) and glass (n = 1.5) at the same 35°. Which bends it more, and why?
Challenge: what is the critical angle for light going from water (n₁ = 1.33) into air? Predict, then check it in the lab.
Free from The Physics Lab · thephysicslab.org · MS-PS4-2: Model how waves, including light, are reflected, absorbed or transmitted through different materials.