DASI-P - Dust/Speaker Selected Response

Hi Kaleb -- this one I designed as a generic sound - not a particular frequency - but I thinks that's too distracting! - So I would love to redo this oen with a simple sine wave sound wave - still a time/amplitude and with very similar student ideas (one with teh same wave at a lower amplitude; one with the dust getting kind of "kicked" by the wave).

What important physics idea is this question targeting?

This question targets whether or not students understand that waves cause vibrations, and that larger amplitude waves will move dust up and down farther but not at a greater frequency (I)
This question checks whether students can connect a common graph of sound (pressure vs. time) to physical movement in the medium — in this case, the back-and-forth motion of a dust particle. (C)
This question targets whether students can describe what happens to matter when sound is present, and how that varies as the sound wave varies. (V)

Which answer best describes what student A's response indicates about their physics understanding?

The student accurately understands that the dust will vibrate as the wave passes, however they seem to think it will vibrate differently than the pattern of the wave itself. (I)
Their drawing shows two common incorrect ideas: that the amplitude/time graph of a sound wave shows how it behaves in x-y space, and that a wave can push the dust forward as it travels. Their writing (that the dust might not always "catch" the sound wave) seems to suggest that the wave might bypass the dust altogether. (C)
This response suggests an emerging awareness of the nature of wave behavior and its capacity to produce observable effects, along with a strong understanding of. vocabulary. (V)

Which of the following options would best support Student A in being able to correctly respond to this question?

I’d hand out representations of air particles with a wave passing through, showing areas of denser particles (high pressure/amplitude) and farther-apart particles (low pressure/amplitude), and ask students to create a pressure/time graph for one location on that representation and then discuss how a dust particle might travel. (C)
I would revisit the first pressure/time graph and ask students to color code where the wave is loudest, and then label various important points (crest, trough, wavelength). We could then discuss how the dust particle is simply part of the medium and responds the same way. (I)
I would ask students to work in groups to discuss how sound interacts with objects and then have each group present their ideas to the class as part of a whole-class discussion. (V)

Which answer best describes what student B's response indicates about their physics understanding?

The student recognizes that the higher amplitude will give the dust particle a stronger push forward but doesn't realize that even the lower amplitude portions of the sound wave can also push the dust particle forward . (I)
This student is correctly describing the dust as getting a push forward from the wave, rather than a push up ; however, it looks like those "pushes" from the wave result in the dust traveling primarily in just one direction, instead of oscillating. (C)
. This student is connecting amplitude, peaks and speed of the wave in productive ways and understands key vocabulary. (V)

Which of the following options would best support Student B in being able to correctly respond to this question?

I’d hand out coiled springs (like a slinky) and ask the students to create a compression wave traveling down the spring that is similar to the sound wave represented in the graph. Once all groups were on the right track, I would have students discuss how to describe the motion of one small section of the slinky as the wave passes through. We would then return to discuss the speck of dust. (C)
I’d hand out coiled springs (like a slinky) and ask the students to create waves that travel down the spring with different amplitudes. Once all groups were on the right track, I would have students discuss if the wave was ever too weak to make the slinky move. We would then return to discuss the speck of dust and what happens for various amplitudes of waves. (I)
I’d hand out coiled springs (like a slinky) and ask the students to create waves that travel down the spring with different amplitudes and describe how various points on the spring move in response to the wave. (I)