Presentation on theme: "Practice IB Lab- Photo Finish (The lab where I help you for the last time.)"— Presentation transcript:
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?
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? *Dont forget to always make observations!! Lets 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 NaHCO 3 : 1.0M 2.0.1M 3.0.2M 4.0.3M 5.0.4M NaHCO 3 is 84 g/mol Example calculation to make 100 mL of 0.2 M NaHCO 3 : (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.