EM Radiation Effects: From Dentists to Wi-Fi

Estimated Time: 45-50 minutes

Materials: Computer with internet access, EM Radiation Effects Simulation

Part 1: Engage (Anchoring Phenomenon)

Have you ever been to the dentist for X-rays? When they take the X-ray, they place a heavy lead apron over your body and the technician steps out of the room. However, you probably have a Wi-Fi router in your home or school right now, emitting electromagnetic (EM) radiation all day long, and no one wears a lead apron to protect themselves from it.

Student Questions:

1. What do you think is the difference between the EM radiation from an X-ray machine and the EM radiation from a Wi-Fi router?
2. Based on this phenomenon, generate two questions you have about how different types of EM radiation interact with matter.

Part 2: Explore (Simulation Investigation)

In this investigation, you will use the EM Radiation Effects on Matter simulation to explore how different frequencies of the electromagnetic spectrum affect biological cells.

Instructions:

1. Open the EM Radiation Effects simulation.
2. Note the initial state of the cells: Temperature is 37.0°C (normal human body temperature) and DNA Damage is 0%.
3. Using the slider at the top, select each band of the EM spectrum one at a time, starting from Radio Waves and moving up to Gamma Rays.
4. For each band, observe the simulation for at least 15 seconds. Record the data in the table below.

Data Table: Radiation Effects

Part 3: Explain (Sensemaking)

Using the data you collected in your table, answer the following questions to make sense of the phenomenon.

1. Identifying Patterns: Look at the “Energy Level” column as you move from Radio Waves to Gamma Rays. As the frequency of the wave increases, what happens to the energy of the wave?
2. Thermal Effects: Which bands of the spectrum caused the temperature of the cells to increase significantly? Did these bands cause any DNA damage?
3. Ionizing Effects: Which bands of the spectrum caused DNA damage? What did you observe happening to the cells (visually) when they absorbed this type of radiation?
4. Cause and Effect: Based on the simulation, explain the relationship between the energy of an electromagnetic wave and its ability to cause cellular damage (ionization). Why does higher energy radiation pose a greater risk to living tissue?

Part 4: Elaborate/Evaluate (Evaluating Published Claims)

You have been asked to review two science articles for a school newsletter. Read the claims below and use the evidence you gathered from the simulation to evaluate their validity and reliability.

Claim 1 (from a blog post “The Hidden Dangers of Wi-Fi”): “Wi-Fi routers emit radio waves constantly. Because radio waves are a form of radiation, leaving your Wi-Fi on overnight will cause the radio waves to ionize your cells, leading to dangerous DNA mutations over time.”

Claim 2 (from a dermatology clinic’s website): “You must wear sunscreen outdoors because ultraviolet (UV) radiation from the sun carries enough energy to ionize atoms in your skin cells. This ionization process damages your DNA, which can lead to skin cancer.”

Evaluation Task: Write a short paragraph evaluating each claim. Your evaluation must:

• State whether the claim is scientifically valid or invalid.
• Use specific data from your simulation table (e.g., specific EM bands, energy levels, and observed effects on temperature or DNA) as evidence to support your evaluation.
• Explain the cause-and-effect reasoning linking the wavelength/frequency of the radiation to the specific type of interaction (thermal vs. ionizing) with the cells.

Extension Options:

• Research how different materials (like lead vs. aluminum) block different bands of EM radiation.
• Investigate the difference between non-ionizing UVA/UVB rays and how different SPF sunscreens block them.

Teacher Notes

Performance Expectation: HS-PS4-4: Evaluate the validity and reliability of claims in published materials of the effects that different frequencies of electromagnetic radiation have when absorbed by matter.

Three-Dimensional Alignment:

• Science and Engineering Practices (SEP): Obtaining, Evaluating, and Communicating Information. Students evaluate the validity of two claims regarding the effects of EM radiation on matter, using data from the simulation as verifying evidence.
• Disciplinary Core Ideas (DCI): PS4.B: Electromagnetic Radiation. Students observe that lower-energy radiation (Radio, Microwaves, IR, Visible) is converted into thermal energy, while shorter wavelength/higher energy radiation (UV, X-Rays, Gamma) can ionize atoms and cause damage to living cells (DNA damage).
• Crosscutting Concepts (CCC): Cause and Effect. Students analyze the cause-and-effect relationship between the frequency/energy of an EM wave and its specific physical effect on a cell (heating vs. ionization).

Evidence Statements Addressed:

1. Obtaining Information (1a): Students are presented with two claims regarding the effect of electromagnetic radiation absorbed by matter (living tissue).
2. Evaluating Information (2a): Students use reasoning about the data presented, including the energies of the photons involved and the probability of ionization, to analyze the validity and reliability of each claim. (They use the simulation data to debunk Claim 1 and support Claim 2).
3. Evaluating Information (2c): Students describe the cause-and-effect reasoning in each claim, linking the specific wavelength’s energy level to the cellular mechanism (thermal vibration vs. DNA ionization).