Two Activities: 1. 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 Carl Pennypacker HOU Conference, June, 2009

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/R 2 Law for brightness vs. Distance (Quick Cams!!) Expansion and Age of Universe Students learn: Real size and scale of solar system planets and distances Use of ratios in making scale models Distance = speed x time 1/R 2 Law for brightness vs. Distance (Quick Cams!!) Expansion and Age of Universe

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

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) 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)

Make a Paper Tape Solar System(cont)! Assume 5 meters is distance from Jupiter to Sun (= 5 “AU’s” 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! Assume 5 meters is distance from Jupiter to Sun (= 5 “AU’s” 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!

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 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

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 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

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. 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.

Now: Shift Gears to Hubble Activity:A word about the Expansion of the Universe With M&M Cookie: Velocities are reasonably easy to measure With Doppler shift in spectra: A Challenge: How to measure Distance!

Calibrated Standard Candles Use a known light source, measure how bright it is -- what variable is left?

Quick Cam Activity: Discover dependence of Brightness on distance for a Standard Candle: 1) Students make a model first -- draw a graph of measured counts of standard candle versus distance -- discuss 2) Take a standard light source, standard exposure with quick cam (or use reference “star”) 3) Measure images with Salsa J 4) Make a graph 5) Make a new model/law

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 M 0 (the Chandrasekhar limit) from Mass Transfer  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 M 0 (the Chandrasekhar limit) from Mass Transfer

` `  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.  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.

Supernova Discovery and Measurement Sequence.

The Sky in Chile By Chris Smith at Cerro Tololo

\ \ The Hubble SpaceTelescope

Supernova Light Curve and Spectrum

SNe Light Curves from the HST and Images

Hubble Curves

Concordance between SNe, CMB and Clusters MM

Dark Energy: ~70% Dark Matter: ~25% Punchline: Energy budget of Universe ~25% ~70%

Expansion Activity #1 Materials: (demo) 1)One sheet (black)“Grid” of Universe at T=1 2)Transparency of expanded Universe at T=2 (red) 3)Transparency marking pen 4)Paper for making a table 5)Graph paper

Expansion Activity #1 cont.) 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 T=1 connecting them to the same galaxy at T=2

Expansion Activity (cont) 4) What do you notice? 5) Untape and re-center on some random galaxy 6) Put arrows on that galaxy Math note: Speed = Distance/time 7) Record the distance to the galaxy and also the speed, which is the length of the arrow (need to understand this)

Expansion Activity (cont) 8)Make a table of distance from the origin and the velocity of each galaxy 9) Make a graph 10) Figure out an age (Hubble constant -1 ) of the Universe, etc.

Expansion Activity (cont) Sloan Supernova Strip Data Expansion Activity (cont) Sloan Supernova Strip Data 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.

` ` The Supernovae! Data from Josh Frieman of the SDSS, University of Chicago Coordinates, redshifts ( z = v/c, where c = speed of light). SNIDRedshiftAKA RA DEC ff22:30: :46: ey2:17: :16: hy0:14: :19: fi0:7: :38: hs3:29: :5: ic21:51: :50:34.6 The Supernovae! Data from Josh Frieman of the SDSS, University of Chicago Coordinates, redshifts ( z = v/c, where c = speed of light). SNIDRedshiftAKA RA DEC ff22:30: :46: ey2:17: :16: hy0:14: :19: fi0:7: :38: hs3:29: :5: ic21:51: :50:34.6

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

Decoding the SDSS (continued)

New Feature: Photometry Tool!  Photometry Tool: Measure How Bright an Object is!!

 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)  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)

Expansion Activity #2 1) Measure Sne 2) Fill in the table 3) Calculate Distance (jiffy formula to convert counts to million light years) 4) Make a Hubble Diagram 5) Get age of Universe

Future of this Unit: 1) “HPL-ize” these activities 2) More pilots (with you all??) 3) Put on web, etc.