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Practice IB Lab- “Photo Finish”. (The lab where I help you for the last time.). How do Different Concentrations of Bicarbonate Solution Affect the Rate of Photosynthesis in Ivy?. Practice Writing Lab using Elodea: used Dissolved Oxygen Probe to measure the amount of oxygen
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Practice IB Lab- “Photo Finish” (The lab where I help you for the last time.)
How do Different Concentrations of Bicarbonate Solution Affect the Rate of Photosynthesis in Ivy? • Practice Writing Lab using Elodea: used Dissolved Oxygen Probe to measure the amount of oxygen • This lab: will use how long it takes an ivy leaf disc that has been compressed to float to the surface of a column of water (indirect measurement)
Why can you use how long it takes a leaf disc to float as an indirect measurement of photosynthesis?
Remembering photosynthesis… LIGHT DEPENDENT REACTIONS LIGHT INDEPENDENT REACTIONS “SYNTHESIS” • “PHOTO”
How do Different Concentrations of Bicarbonate Solution Affect the Rate of Photosynthesis in Ivy? • What is a rate? • Is a rate measured directly? • What would your raw data be? *Don’t forget to always make observations!! Let’s look at the procedure.
Why do the discs sink? DENSITY! The spaces have been filled with solution.
IDV: 5 concentrations of bicarbonate solution • IDV levels of NaHCO3: • 0M • 0.1M • 0.2M • 0.3M • 0.4M • NaHCO3 is 84 g/mol • Example calculation to make 100 mL of 0.2 M NaHCO3: • (0.2 mol/L)(0.1 L)(84 g/mol)
In order for you to answer the question, you need to calculate a rate. • What 2 pieces of data have been directly collected? • What is this called in your lab write up? • You need to collect sufficient data. How many trials minimum? • What do you do next with these trials of time & distance data? • Step 1: • Step 2: • Which type of processing would be considered too basic to be given Data Processing credit? • What could you do that would take this data further (beyond rate)? • -Ex: % difference between IDV “A” (control ) and IDV “B”, IDV “C”, etc.