Presentation on theme: "Practice IB Lab- “Photo Finish”"— Presentation transcript:
1Practice IB Lab- “Photo Finish” (The lab where I help you for the last time.)
2How 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 oxygenThis 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)
3Why can you use how long it takes a leaf disc to float as an indirect measurement of photosynthesis?
6How 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.
9Why do the discs sink?DENSITY! The spaces have been filled with solution.
10IDV: 5 concentrations of bicarbonate solution IDV levels of NaHCO3:0M0.1M0.2M0.3M0.4MNaHCO3 is 84 g/molExample calculation to make 100 mL of 0.2 M NaHCO3:(0.2 mol/L)(0.1 L)(84 g/mol)
11In 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.