Two Activities: 1. A Paper Tape Scale

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Two Activities1. A Paper Tape
Scale Solar System 2. The Size and Age of the
Universe from Supernovae(both in early pilot)

• Carl Pennypacker
• HOU Conference, June , 2009

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Learning Goals

• Students learn
• Real size and scale of solar system planets and
  distances
• Use of ratios in making scale models
• Distance speed x time
• 1/R2 Law for brightness vs. Distance (Quick
  Cams!!)
• Expansion and Age of Universe

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Note on Pedagogy

• Elicit Preconceptions
• Make a first attempt model
• Discuss the Why of their model in groups,
  class, etc.
• Measure/evidence
• Make a new model

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Make a Paper Tape Solar System!Rich Lohman has
co-developed this unit(Just Earth, Sun, and
Jupiter)Materials

• 5 meter paper tape 1 AU 1 meter
• Big sheet of paper for Sun, Earth, Jupiter
• Protractors (string) for making Big circles
  for scale sun- planets
• Scissors for cutting out planets
• Meter Stick
• Tape
• Work sheet (for refining estimates)

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Make a Paper Tape Solar System(cont)!

• Assume 5 meters is distance from Jupiter to Sun
  ( 5 AUs
• Earth is at 1 AU -- the Sun is at one end,
  Jupiter at other.
• 1 AU 1 meter is the distance from the sun to
  the earth.
• Without thinking, search your heart and
  emotions for the best size circle (draw and cut
  out) that matches the scale size of the Earth,
  the Sun, and Jupiter. Students usually make sun
  as big as paper. They seem to get ratios right,
  though.
• There Is no wrong answer!! Go for it!
• Share your model with the class -- why do they
  choose these models. Let them luxuriate in these
  neurons and synapses of their great first models!

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Make a Paper Tape Solar System!

• Go to computers and open SalsaJ, and measure
  the size of the Sun, Earth, and Jupiter.
  Desktop
• Fireball.fts Jupiter 1 pixel 340 km
• Sun Sun1 1 pixel 4100 km
• Earth_from_mars Earth 1 pixel 220 km

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Make a Paper Tape Solar System!

• Go to computers and open SalsaJ, and measure
  the size of the Sun, Earth, and Jupiter.
  Desktop
• Fireball.fts Jupiter
• Sun1 Sun 1 pixel
• Earth_from_mars Earth

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Make a Paper Tape Solar System!

• Find the size in kilometers of the Sun,
  Jupiter, and the Earth.
• Convert kilometers into millimeters by
  dividing by 150,000. (cookbook for now -- need to
  drill down!)
• Remake your model.
• Class Discussion -- have to figure out how
  not to make teacher seem like too much a smarty
  pants and students too naïve.

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Now Shift Gears to Hubble ActivityA word about
the Expansion of the Universe With MM Cookie
Velocities are reasonably easy to measure With
Doppler shift in spectra A Challenge How to
measure Distance!
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Calibrated Standard CandlesUse a known light
source, measure how bright it is -- what variable
is left?
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Quick Cam ActivityDiscover
dependence of Brightness ondistance for a
Standard Candle1) Students make a model first
-- draw a graph of measured counts of standard
candle versus distance -- discuss2) Take a
standard light source, standard exposure with
quick cam (or use reference star)3) Measure
images with Salsa J4) Make a graph5) Make
a new model/law
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Why are all the Type Ia SNe of nearly the same
brightness?

• When a star of near Solar Mass uses up all of its
  Hydrogen and Helium it collapses to a White
  Dwarf. (W.D.)
• If the White Dwarf has a companion star then, for
  the right conditions, Mass can be Transferred to
  the W.D.
• Type Ia SNe are due to the explosion of a W.D.
  This occurs when it reaches a mass of 1.4 M0
  (the Chandrasekhar limit) from Mass Transfer

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• The star of about the size of the Sun becomes a
  White Dwarf about the size of the Earth.
• The WD consists of carbon and oxygen nuclei and a
  free electron gas.
• The Supernova explosion occurs when the
  gravitational pressure exceeds the electron gas
  pressure.

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Supernova Discovery and Measurement Sequence.
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The Sky in Chile
By Chris Smith at Cerro Tololo
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\
The Hubble SpaceTelescope
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Supernova Light Curve and Spectrum
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SNe Light Curves from the HST and Images
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Hubble Curves
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Concordance between SNe, CMB and Clusters
?M
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Punchline Energy budget of Universe
Dark Energy 70
Dark Matter 25
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70
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Materials (demo)1) One sheet (black)Grid of
Universe at T12) Transparency of expanded
Universe at T2 (red)3) Transparency marking
pen4) Paper for making a table5) Graph paper

• Expansion Activity 1

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1) Tape down T 1 Universe (paper)2) Tape
down with T 2 Universe (transparency) 3)
Tape down blank transparency and carefully draw
arrows from the same galaxies at T1 connecting
them to the same galaxy at T2

• Expansion Activity 1 cont.)

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4) What do you notice? 5) Untape and
re-center on some random galaxy6) Put arrows
on that galaxyMath note Speed
Distance/time7) Record the distance to the
galaxy and also the speed, which is the length of
the arrow (need to understand this)

• Expansion Activity (cont)

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8) Make a table of distance from the origin and
the velocity of each galaxy9) Make a
graph10) Figure out an age (Hubble
constant-1) of the Universe, etc.

• Expansion Activity (cont)

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The Sloan Digital Sky Survey telescope
undertook a focused study of a strip of the sky
and discovered over a hundred Type Ia
supernovae. We have five good ones from them to
use.

• Expansion Activity (cont)
• Sloan Supernova Strip Data

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• The Supernovae!
• Data from Josh Frieman of the SDSS, University of
  Chicago
• Coordinates, redshifts ( z v/c, where c
  speed of light).
• SNID Redshift AKA RA DEC
• 1241 0.087 2005ff 223041.41
  -04635.7
• 2308 0.148 2005ey 2175.49 01649.1
• 5550 0.156 2005hy 01423.59 01959.0
• 2422 0.265 2005fi 0758.69 03817.5
• 5391 0.301 2005hs 32922.08 -1540.9
• 5844 0.311 2005ic 21518.69 -05034.6

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• Decoding the SDSS
• (in this activity, the SDSS is used to find the
  supernovae)

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• Decoding the SDSS (continued)

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• Decoding the SDSS (continued)

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New FeaturePhotometry Tool!

• Photometry Tool Measure How Bright an Object is!!

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• Photometry Tool Measure How Bright an Object
  is!! (find Sne first)
• 1) Click on photometry tool
• 2) Click on star you want to read
• 3) Read off intensity (in counts) (photometry
  measures all of the counts within a circular
  ring, and subtracts off background)

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1) Measure Sne2) Fill in the table 3)
Calculate Distance (jiffy formula to convert
counts to million light years)4) Make a Hubble
Diagram5) Get age of Universe

• Expansion Activity 2

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1) HPL-ize these activities2) More pilots
(with you all??) 3) Put on web, etc.

• Future of this Unit