Education Round Table Notes, 2/11/02

  1. Teaching Parallax

    Several suggestions were made for demonstration to use for teaching parallax

    1. MPEG movie illustrating parallax available at
    2. Table top parallax demo - see found in the Project Star materials stored in video cabinet pg 101
    3. Lab using candles spread out in a large room (see Gretchen for copies)
    4. ASTR 101 lab on the PCs
    5. Mandy's student stars - bring students to the front of the room. Have them look at the relative position of the people still sitting in the desks in the front rows compared to the rows behind them from different sides of the room.
    6. Former lab set up used four light bulbs in a row at one end of the hallway. Polaroid pictures taken from either side showed a shift in position. This can be recreated now that the department has digital camera - Gretchen will work on bulb holder.
    7. Video game example - How do you tell foreground from background objects in video games? Size differences in one part. However, if you have a space ship that you are flying around, foreground objects moving quicker than background is your other visual clue.
    8. Video - the Meeks series of videos (A30-35) includes one on parallax and proper motion.

    Student understanding of parallax: There was some discussion of what students do and don't understand about parallax and what it is important for them to know.

    • Closer things appear to shift more than further things - this concept seems to be understood
    • The shift in position allows you to calculate distance - this seems to be the more difficult portion to understand. Trig phobia
    • Suggested that one solution to this may be to develop a lab where you are given a particular shift in star position and then you must change the distance of the star from the Earth until the matching position shift is achieved.
    • Some savvy students ask about the fact that all stars shift, so what do you use for reference points. Other also ask about whether or not the sun moves.
  2. Magnitude

    Some demonstrations

    • Push pin chart of magnitude differences will be stored in poster/demo room
    • In progress - four light sockets together with different wattage bulbs - preferably on rheostats.
    • Backward nature of numbering system easier to understand in ordinals (1st magnitude, 2nd magnitude)
    • Cole uses a movie star analogy - first magnitude stars get a higher box office pull and thus are worth a higher salary, etc.

    Is it necessary to teach magnitudes?

    • 120/121 text gets around the magnitude system by talking in terms of "relative brightness. Derek presents traditional magnitude system and uses discussions of B-V, redder or bluer? to get across the anti-intuitive nature of the system.
    • From a general 100 literacy perspective, the term will come up in any article in the newspaper or a magazine that is intended to get someone to go look at an object in the sky.
  3. Scale

    Some models available:

    • Beach Toy Solar System: All the pieces necessary plus info on the distance they would need to be spread. Can now be found in the poster/demo room.
    • The Tennis Ball Sun: A set of stellar size comparison objects where the sun is a tennis ball. Can be found in the poster/demo room
    • Grace has an exercise that puts the solar system on a football field.
    • Toilet paper solar system - see Gretchen for a table with numbers
  4. Concerns brought up by TAs
    • EM Spectra - This remains major stumbling block for ASTR100 students. Mandy's adaptation of the 101 spectra lab to her discussion section worked well, but she still feels there is a way to go in raising student interest in this field. Other things tried in Cole Miller's class last semester on this topic included Jonathan King playing the electric guitar in class - one note for one line, a chord for a group of lines, and white noise. This is still an issue that needs more thought.
    • Luminosity and Flux - Jimmy was looking for analogies to assist with this concept.
      • Jimmy's example - amount of rain hitting windshield (flux), amount of rain from cloud(luminosity)
      • Mandy's example - Spraying a hose at a bucket. Amount of water in bucket (flux), amount of water coming from hose (luminosity). Mandy also uses for direct and indirect light (bucket straight on vs bucket at an angle)
      • Derek's example - Total energy coming from a campfire is greater than that coming from a blow torch - greater area emitting energy.

Next time: Jimmy and Mandy reveal their methods for teaching students to do math.......

Mandy Proctor
Kelly Shockey
Rahul Shetty
Jimmy Hague
Halim Nablant
Cole Miller
Derek Richardson
John Trasco
Grace Deming
Gretchen Walker