Lesson 2 - Refraction and Total Internal Reflection
Overview:
In this lesson you will review some more material from earlier grades in optics. An will be able to see properties that can be explained if you think of light as a wave, but also could be explained by thinking of light as a particle. We will explore this idea in further lesson: light, wave or particle?
Curriculum Expectations:
Overall Expectations:
E1. Analyse technologies that use the wave nature of light, and assess their impact on society and the environment.
E2. Investigate, in qualitative and quantitative terms, the properties of waves and light, and solve related problems.
E3. Demonstrate an understanding of the properties of waves and light in relation to diffraction, refraction, interference, and polarization.
Specific Expectations:
E1.1 Analyze, with reference to the principles related to the wave nature of light, a technology that uses these principles (e.g., Xeon lights, spectroscopes, polarized sunglasses).
E2.1 Use appropriate terminology related to the wave nature of light, including, but not limited to: diffraction, dispersion, wave interference, nodal line, phase, oscillate, polarization, and electromagnetic radiation.
E2.3 Conduct inquiries involving the diffraction, refraction, polarization, and interference of light waves (e.g., shine lasers through single, double, and multiple slits; observe a computer simulation of Young’s double-slit experiment; measure the index of refraction of different materials; observe the effect of crossed polarizing filters on transmitted light).
E3.2 Describe and explain the diffraction, refraction, polarization, and interference of light waves (e.g., reduced resolution caused by diffraction, mirages caused by refraction, polarization caused by reflection and filters, thin-film interference in soap films and air wedges, interference of light on CDs).
E3.3 Use the concepts of refraction, diffraction, polarization, and wave interference to explain the separation of light into colours in various situations (e.g., light travelling through a prism; light contacting thin film, soap film, stressed plastic between two polarizing filters).
E1. Analyse technologies that use the wave nature of light, and assess their impact on society and the environment.
E2. Investigate, in qualitative and quantitative terms, the properties of waves and light, and solve related problems.
E3. Demonstrate an understanding of the properties of waves and light in relation to diffraction, refraction, interference, and polarization.
Specific Expectations:
E1.1 Analyze, with reference to the principles related to the wave nature of light, a technology that uses these principles (e.g., Xeon lights, spectroscopes, polarized sunglasses).
E2.1 Use appropriate terminology related to the wave nature of light, including, but not limited to: diffraction, dispersion, wave interference, nodal line, phase, oscillate, polarization, and electromagnetic radiation.
E2.3 Conduct inquiries involving the diffraction, refraction, polarization, and interference of light waves (e.g., shine lasers through single, double, and multiple slits; observe a computer simulation of Young’s double-slit experiment; measure the index of refraction of different materials; observe the effect of crossed polarizing filters on transmitted light).
E3.2 Describe and explain the diffraction, refraction, polarization, and interference of light waves (e.g., reduced resolution caused by diffraction, mirages caused by refraction, polarization caused by reflection and filters, thin-film interference in soap films and air wedges, interference of light on CDs).
E3.3 Use the concepts of refraction, diffraction, polarization, and wave interference to explain the separation of light into colours in various situations (e.g., light travelling through a prism; light contacting thin film, soap film, stressed plastic between two polarizing filters).
Success Criteria:
- Describe refraction and draw a diagram that shows this phenomena.
- What is the index of refraction?
- Does the frequency change when waves travel through different mediums?
- What does Snell's Law help us to calculate?
- Describe using diagrams how total internal reflection occurs, make sure to include the critical angle.
- Which equation can be used to calculate the critical angle?
- How do fibre optics use reflections?
Time Allocation: 4 hours
Learning Activities:
Read pages 444 - 457 from Nelson 9.2
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Bending Light
Explore bending of light between two media with different indices of refraction. See how changing from air to water to glass changes the bending angle. Play with prisms of different shapes and make rainbows. |
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In the playlist below, video:
- Will introduce the concepts of light refractions and show you how to find the angle of refraction when a light rays goes from air to water.
- Will show you how to find the displaced distance when a light ray goes from air through glass then out to air again.
- Will show you what happens to a light ray when it goes from water to air at various angles.
- Will show you how to calculate the maximum angle of refraction so the inbound ray will not "escape" out of the fiber optic cable.
Task:
Solve questions 6, 7, and 8 from Nelson 9.2 Review on page 458.
Optional Extension:
Optional Extension:
- Solve questions 9 and 10 on page 458.
Reflect:
In what areas of your daily experience do you now see the physics concepts that were explored in this section?
