Wednesday, May 14, 2014

HS - PS4.A (C) - Electromagnetic Waves - ASSIGNED (AM 5/10/2014)

Module: Electromagnetic Waves
DCI: PS4.A (C) Waves can add or cancel one another as they cross, depending on their relative phases (i.e., relative position of peaks and troughs of the waves), but they emerge unaffected by each other. (Boundary: The discussion at this grade level is qualitative only; it can be based on the fact that two different sounds can pass a location in different directions without getting mixed up.)

PE: HS-PS4-3 Evaluate the claims, evidence, and reasoning behind the data that electromagnetic radiation can be described either by a wave model or a particle model and that for some situations one model is more useful than the other.

[Clarification Statement: Emphasis is on how the experimental evidence supports the claim and how a theory is generally modified in light of new evidence. Examples of a phenomenon could include resonance, interference, diffraction, and photoelectric effect.] [Assessment Boundary: Assessment does not include using quantum theory.]

The ideas here are: 
- waves can add to each other as they cross
- waves can cancel each other as they cross
- the phase of each wave will determine whether they add or cancel
- after two waves cross each other, they come out unaffected

This PE will be tricky to write for, because this particular PE applies to another standard, which explicitly states that Electromagnetic waves can be explained with both a wave model and a particle model.  For this standard, the wave model is a better fit because no matter can occupy the same space at the same time.  So, the particle model of a wave is not useful when talking about constructive or destructive interference. 

Possible Questions: 
"The use of the wave model of Electromagnetic Radiation is more suitable to a discussion of how waves can cross each other without being affected because - "

We can use this image... from STEMscopes, to write a question.... 


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