2.1 Senses and Instrumentation

Learning Goals

[Link to PlayPosit]

[Link to instructional video]

More details on the SSS website

After this lesson, students should

1. Place appropriate trust in instruments where direct observation is not possible (or is less precise/accurate).
2. Understand that interaction with reality through instruments can extend the belief of a shared objective reality to objects and phenomena to which our raw senses do not have direct access.
3. Understand the challenges of validating an instrument and methods of validation.

Definitions

Term

Explanation.

Examples

1. [item 1]

Common Misconceptions

1. Template:Quote response

Context

[Explanation of how the current topic into the larger context of the course by explaining how the previous topic(s) relate to the current topic and leaving cliffhangers for future topics where relevant throughout the lesson]

Before

X.X Lesson Name

Explanation.

After

X.X Lesson Name

Explanation.

Recommended Outline

Before Class

• [Any essential logistical things that need to be done for this class]
• Prepare a seating chart.
• Review PlayPosit and discussion questions and ask faculty, Gabriel, or Emlen any questions you have.
• (Optional) Prepare a presentation.

During Class

• (5 min) Come up with some fun way to assign the roles of spokesperson and notetaker (e.g. earliest birthday in the year, lives furthest from campus). Remind them of the responsibilities of these roles.
• ([#] min) [Description of some module from #Lesson Content]
• (5 min) Collect questions for plenary.

Lesson Content

Discussion Questions

1. Question
   1. Option 1
   2. Options 2

Activity 1: Spectra of Sound

In this activity, students use a spectrogram app on their phones to interactively explore the frequency composition of different sounds and voices. Seeing the spectrogram immediately respond to different sounds should give the students a sense that it’s measuring something real. This can be concluded because the spectrum showed in the app clearly and consistently respond to the sounds the students expose it to.

Instructions

1. Prior to class, make sure the students download a spectrogram app on their phones.
2. (2 min) Introduce the activity by opening the app on your phone and singing or whistling out loud into it. But, don’t show them the results of your measurement.

1. (8 min) Have the students explore different sounds with the apps.
   1. Have the students investigate the sounds of their singing/whistling and different voices/sounds as well as high and low pitched notes from any musical instruments if they have them available.
   2. Encourage them to look at the differences between the spectra for the different voices and sounds.
2. (4 min) Have the students discuss the discussion questions in small groups.
3. (4 min) Discuss the questions as a class.

Discussion Questions

1. Based on your observations, how could you distinguish the various sounds, if you were given the spectrogram alone (but not your own sense of sound)?
2. How can you interact with this spectrogram to assure yourself that the instrument is showing something real about the world?

Activity 2: Spectra of Light

This activity has students use small diffraction gratings to look at the spectrums produced by various light sources. By interactively observing the different patterns diffracted out by different types of lights, the students should be able to see that there is some structure to light that they can’t easily observe with their naked eyes. The students can trust their instruments because they see the results consistently and in direct response to their measurements.

SSS Demo

Instructions

1. (2 min) Get everyone set up with their diffraction gratings and demonstrate looking through one.
   • If this is in person, provide the students with diffraction gratings.
   • If this is remote, make sure the students have their diffraction gratings handy or have some old CD they can use instead. If students don’t have either, ask them to virtually follow along with a group member.
2. (8 min) Have the students look at different sources of light. They should try looking at the sunlight (but not at the sun directly) as well as the LED lights on a phone or other electronic device.
3. (4 min) Have the students discuss the discussion questions in small groups.

Discussion Questions

• How can you interact with this grating film/CD to assure yourself that the instrument is showing something real about the world?
• Based on your observations, how could you distinguish the various light sources, if you were given the diffraction grating film alone (but not your own sense of vision)?

Activity 3: Slinky Drop

For this activity, each group will need one slinky and one smartphone with slow motion camera capability.

Veritasum's Demo

SSS Demo

Instructions

1. Hold on to one end of the slinky and let the whole slinky naturally hang down. The bottom of the slinky should not touch the ground. If the slinky is too long, you may hold onto many rings at once, so that the remaining length does not touch the ground.
2. Once the slinky is steady (not bouncing or swinging), let go of it to allow it to fall to the ground.
3. Question: What is happening to the bottom of the slinky just after you release it?
   1. It is falling at the same speed as the top of the slinky.
   2. It is falling slightly slower than the top of the slinky.
   3. It is falling slightly faster than the top of the slinky.
   4. It is not falling at all.
   5. It is moving upwards.
4. Question: What is happening to a ring in the middle of the slinky just after you release it?
   1. It is falling at the same speed as the top of the slinky.
   2. It is falling slightly slower than the top of the slinky.
   3. It is falling slightly faster than the top of the slinky.
   4. It is not falling at all.
   5. It is moving upwards.
5. Have other group members repeat this.
6. Now, with one person holding the slinky as in step 1, have a second person record a slow motion video of the slinky from a distance using a smartphone camera. You can maximize slowness on iPhones by clicking the number in the upper right corner from 120 to 240 (frames per second). Other phones may have “slo mo” and “super slo mo” options. Make sure the video includes the entire slinky and the floor. Keep the camera steady throughout the recording.
7. As a group, review the slow motion video and answer the above questions again.
8. Play Around: What else can you do with a slinky? Can the slow motion camera help you see other movements of the slinky more clearly? (E.g. stretch out the slinky between two people and have one person jolt it, while a third person records.) Feel free to play around and experiment. How does your interactive exploration of the slo mo videos of the slinky help you believe the video is showing what’s happening AND reveal how the slinky is really moving?

Discussion Questions

1. In all the instruments we’ve looked at, we’ve directly compared them with our senses. How do we know we can even rely on our senses? How do we know when we can't?

1. How can we observe a thing that we can never perceive directly with our senses?

1. Not all instruments are as directly interactive as the ones we’ve used here. Describe an entity which you believe exists for which you have only very indirect evidence.
   1. Why do you believe it exists?
   2. Is there anything that might convince you it did not exist?
   3. Is there anything that might convince you that although something like it does exist, it has quite different properties than you had thought?