Wave Technology: Information & Energy

Part 1: Engage (Anchoring Phenomenon)

How do we capture energy from the sun to power homes, and how do we stream high-definition video across oceans?

Every day, humanity relies on invisible waves. Sunlight travels 93 million miles through space, carrying energy that can be captured and converted directly into electricity to power our lives. Meanwhile, pulses of light carry vast amounts of digitized information—emails, videos, phone calls—through thin glass cables beneath the oceans.

Part 2: Explore (Simulation Investigation)

In this investigation, you will use the simulation to explore two core technologies: Solar Cells (Energy) and Fiber Optics (Information).

Investigation A: Solar Cells & Energy Capture

  1. Ensure the simulation is set to the Solar Cell tab.
  2. The simulation shows a solar cell (P-N junction) connected to a circuit.
  3. Set the Light Intensity to 100% and Sun Angle to 0°.
  4. Adjust the Light Wavelength slider from 400 nm (violet/UV) up to 800 nm (infrared/red).
  5. Record your observations in the table below. Does the solar cell produce power at all wavelengths?
Wavelength (nm) Produces Power? (Yes/No) Power Output (W) Observations (Are electrons moving?)
400      
500      
600      
700      
750      
800      
  1. Find the exact wavelength threshold (Bandgap) where the solar cell stops producing power.
    • Threshold Wavelength: __ nm

Investigation B: Fiber Optics & Information Transmission

  1. Switch to the Fiber Optics tab in the simulation.
  2. The simulation shows light entering a glass core surrounded by cladding. Pulses of light (data “1s”) are being injected.
  3. Set Core Index (n) to 1.48 and Cladding Index (n) to 1.40.
  4. Adjust the Entry Angle and observe what happens to the light ray and the data pulses.
  5. Record your observations in the table below. Does the data escape (Data Lost) or stay in the core (Successful TIR)?
Entry Angle (Degrees) Status (Successful / Data Lost) Observations (What happens to the light at the boundary?)
10    
20    
25    
30    
40    
  1. Find the exact maximum entry angle where the transmission remains “Successful” before it becomes “Data Lost”.
    • Maximum Entry Angle: __ degrees

Part 3: Explain (Sensemaking)

Using the data from your exploration, answer the following questions to explain how these devices use basic physics principles.

  1. Solar Cells (Photoelectric Effect): Based on Investigation A, explain why the solar cell only produces power at certain wavelengths. What does this tell you about the relationship between wave frequency (or wavelength) and the energy needed to free electrons in the material? (Hint: Consider the concept of a bandgap and the photoelectric effect. Recall that shorter wavelengths have higher energy.)

  2. Fiber Optics (Total Internal Reflection): Based on Investigation B, describe the conditions required for “Total Internal Reflection” (TIR) to occur. Why is TIR essential for transmitting information over long distances?

  3. Digital Information: The pulses in the fiber optics are discrete “1s” (and the spaces are “0s”). According to the simulation context, why is information often digitized and sent as discrete wave pulses rather than as continuous analog waves?

Part 4: Elaborate/Evaluate (Argumentation & Modeling)

Your Task: Communicate technical information about how these two devices use wave behavior and interactions with matter to function, and why modern civilization depends on them.

Choose a format (e.g., a written technical report, an infographic, or a recorded presentation) and fully describe both devices (Solar Cell and Fiber Optic Cable).

Your communication must include:

  1. Physics Principles: Describe the specific wave behavior or wave-matter interaction utilized by each device.
    • Solar Cell: Explicitly describe the absorption of photons and the production of electrons (the photoelectric effect) to convert electromagnetic energy into electrical energy.
    • Fiber Optic Cable: Explicitly describe total internal reflection at the core/cladding boundary used to transmit digitized signals over long distances.
  2. Technological Application: Discuss how research and development produced this functionality (e.g., engineering the materials’ refractive indices or bandgaps).
  3. Cause and Effect: Identify the cause-and-effect relationships (e.g., Cause: incident light wavelength is shorter than the bandgap; Effect: electrons are excited and current flows).
  4. Real-World Impact: Discuss the real-world problem each device solves or the need it addresses, and how modern civilization now depends on these technological systems.

Teacher Notes & Alignment

Performance Expectation:

Evidence Statements Addressed:

  1. Communication style and format: Students use at least two different formats (e.g., textual and mathematical/graphical representations in their report) to communicate technical information and ideas, including fully describing at least two devices (Solar Cell, Fiber Optics) and the physical principles upon which they depend. One device depends on the photoelectric effect.
  2. Connecting the DCIs and the CCCs:
    • When describing how each device operates, students identify the wave behavior utilized by the device (total internal reflection in fiber optics) or the absorption of photons and production of electrons for devices that rely on the photoelectric effect (solar cells).
    • Students qualitatively describe how the basic physics principles were utilized in the design through R&D (e.g., using the photoelectric effect to produce an electric current, designing refractive index boundaries to confine light).
    • For each device, students discuss the real-world problem it solves (clean energy capture, high-speed data transmission) and how civilization depends on it.
    • Students identify and communicate the cause and effect relationships used to produce the functionality (e.g., angle of incidence causing TIR, wavelength causing electron excitation).

Alignment:

Implementation Guidance: