Transcript Slide 1
Updates • Last week’s quiz average: 74% Let’s review it… • Fermentation with a bullet lab report grades will be posted tonight, graded lab reports will be in D2L Dropbox comments • I still need Peer Evaluations for the genetic disease projects • Pay attention today and take notes throughout the lab. You have a report due next week Goals • To test a common claim from textbooks • To build and understand tools you’re working with – recall: otherwise, it’s simply not science. It’s magical mumbo-jumbo • To generate meaningful data that allows drawing of conclusions. And to draw them • Consider implications of plants being ‘green’ • Use O2 creation as a measurement of photosynthesis (Have we done this before?) Here’s an assertion… Photosynthesis in (green plants) is more effective at the ends of the spectrum than in the middle Can we test this? HOW can we test it • What did we do with leaves last week? – Leaf assay – Graph of absorption spectrum • How did that happen? • How can you make your data meaningful? Getting Started • • • • • Groups 1 & 4: liquid permitting red light Groups 2 & 5: liquid permitting green light Groups 3 & 6: liquid permitting blue light ALL: Make enough to share (yours + 2 others) 20ml for each group No less than 0.2 at ‘your’ wavelengths; no greater than 2 at others Getting Started • • • • Groups 1 & 4: liquid permitting red Absorbance at ‘your’ light wavelengths be Groups 2 & 5: liquidshould permitting green LESS light THAN 0.2 Groups 3 & 6: liquid permitting blue And no greater than ~2.0 light at Make other wavelengths ALL: enough to share (yours + 2 others) Buffers • Ca++ and PO4-- precipitate • So, TWO different 10X buffer components • Add ONE of the them last or get a solid What will it look like? • • • • • Need to place disks in at same time? What do you time? Does volume/beaker matter? Does concentration matter? How can you make comparisons valid? Consider… • What is the mechanism by which we are ‘removing’ some wavelengths of light? • Implications for volumes of beakers? • Consequences if red sits waiting while you work with blue and green It’s a “Helper” Red = 630 and 660 Your data are • ‘Start Table’ Blue = 350 and 430 based on a “1X” • Enter your data Green = 500 and 590 Solution. Dyes in back are 10X • Use sliders Dilute your dyes with distilled water Absorbance no more than 0.2 at your wavelength!!!! • Use ‘Plotulence’ to develop your dye cocktail • Sliders indicate how much more concentrated than last week • All ‘mixers’ are 10X (NOT 1X!) – if you make 100 mL, how many mLs are the two ‘buffers’? Water? (To make 1X final solution) • Check with other group of same color • We’re not making artificial hearts or sending a probe to Mars Mix It • • • • Remember there are TWO ‘buffers’ Compare your plan to other group’s Mix your color Trade ‘colors’ with your friends; collect all three!!!! • Get your disks • Float ‘em What if one ‘color’ is darker? • • • • • • • Test your color using specs Graph your data using smoothed curves Cut out the graph ABOVE line Weigh it; record it; compare it What does that number represent? Y-axis:4th major line from bottom as 2.0 abs X-axis: each major line is 100nm; plot 300700 nm • Give your graph weight to ‘sharing’ groups! What Now? • Did you find what you expected? • Stones left unturned? • Differences in graph weights? – Red, graph 3g, floated in 5 min – Blue, graph 2g, floated in 7 min • Adjusted speed? This is a critical part of your experiment. Failure to explain and deliver this calculation = loss of points on write up