1. 1 Light Tools Building and confirming tools for inquiry How?Why?

2. 2 Think with me Why do you see colors when some chemicals are flamed? Why do different chemicals => different colors? Assertion I: (proposed model): unlike planets, electrons are only allowed discrete energies* Assertion II: Energies that don’t take an electron to an allowed place are ignored by it *If the earth should stop revolving, Spinning slow enough to die... --IF, David Gates (Bread)

3. 3 Hydrogen Atom Simulator (Dan Damelin) http://chemsite.lsrhs.net/FlashMedia/html/flashEMR.htm Also in Further Explorations Predict: what happens to an arbitrary-energy photon? Predict: what happens to one that matches a difference between current & potential orbital? Predict: what happens to one that matches a difference between current & potential orbital? Set ‘pause mode’ to on

4. 4 Tool using

5. 5 How are these different? Using a thermometer to test temperature pointing stick at sky, say magic words, wait for rain using ‘pH paper’ to count ‘protons’ using the Ba(OH) 2 ‘test for’ carbon dioxide counting geigs with a Geiger counter believing in ‘global climate change’ Any sufficiently advanced technology is indistinguishable from magic. --Arthur C. Clarke

6. 6 Rankings Empirical--you saw it, touched it, etc. Reasoned argument from documented/identified assumptions & previous knowledge Repeatedly established by others Never : assertions by authority regardless of the nature (or volume) of that authority

7. 7 Suck it & see We’ll have tubes with chalk or filter paper; drop these in the specs Look at the beam (far red may be hard to see) slowly and carefully move the wavelength selector Look again Reset spec

8. 8 Driving Ms. Spec Set for infinite absorbance (blocked path) Set wavelength Set zero absorbance

9. Principles of spectrophotometry Absorption? Re-emitted? What will density do to readings?

10. 10 Calibrating your eye Graph paper pp. J-13 to 20 Predict: how will a blue liquid absorb? A green one?

11. 11 To your specs! On your desk is a bank of tubes Find the absorbance of each

12. 12 Data 350430500590630660 Blue Violet Red Green Yellow Leaf This should take 15’.

13. 13 Graphing Create a graph, table for HW See rubric!!!

14. 14 FYI: Dye Structures Crystal Violet Yellow Napthol Green FDC Blue1 FDC Red 3 FDC Yellow5

15. 15 The Joy of Dilution What fraction of molecules would you have to remove for there to be 1/2 as many collisions between beam & dye? OK, build a solution with 1/4 absorbance of stock; confirm Tubes will be covered

16. 16 Photosynthesis “Makin’ things with light*” *Lite-Brite ad jingle

17. 17 Photosynthesis: Intro

18. 18 What’s in a leaf Predict: what will we find when we grind up a leaf? Protocol: p. 11-3 Graph absorption of spinach extract ‘ultra’-violet light it (high or low energy)? Note!! These wavelengths re-do your DNA!!

19. 19 Flight of the electron

20. 20 Thinking it through Is the reddish light emitted being used for photosynthesis? What would happen if we applied a drug that BLOCKED electron transport?

21. 21 Fashioning an assay Using the oxygen that plants belch out

22. 22 Deflating, inflating a leaf How can you tell if photosynthesis is happening? What are the inputs? The products? How can you test for these?

23. 23 Next week! You’ll take the data you have from this week to create a red-passing, blue- passing or green-passing solution This will be used to test whether different portions of the visible spectrum are equally potent for photosynthesis Sadava, Life, Fig. 8-6

24. 24 Semester project!

25. 25 Homework Table & Graph of absorbance data Dilution worksheet (pp. 11-9 & 10) Table & Graph of absorbance data Dilution worksheet (pp. 11-9 & 10)

26. 26 Old stuff

27. 27 Ex. 3, cochineal crimelab, optional

28. 28 Science vs. Magic I shake my pointy stick at the third mountain during the rise of the new moon in the time of the exodus of the birds I add the sample and the stuff the police brought to the two tubes and put them into the ‘PCR machine’ I take the stuff and put it into the ‘HPLC machine’ and little spikes appear at some distances on the graph thing. The rains come! The ‘bands’ on the ‘gel’ look the same! Carboxymethylhypoxanthine I commune with the god of the rains. Please me or the droughts come. Col. Mustard with the lead pipe in the conservatory I ‘understand’ the enzyme mechanism! Any sufficiently advanced technology is indistinguishable from magic. --Arthur C. Clarke Action Conclude Result