IB lab Design photosyntesis

Lab Design
Research question: How does temperature affect on the rate of photosynthesis?
Variables:
Independent variables: temperature of water where the elodea(plant) is going to be placed
Dependent variable: the amount of oxygen produced by photosynthesis reaction
Control variables:
Light concentration entering the beaker
Length of the plant
Volume of the water to be precise
And of the NaHCO3
What is the variable to be controlled.
Why does it need to be controlled.

How will you control it
Light concentration
Light may affect the oxygen produce as it may speed up the reaction of the light is greater in one of the beakers
Having both of the beaker on the same light environment
Length of the plant
Length of the plant need to be the same as it is more easy to produce photosyntesis where plants is bigger, so bigger the reaction
Having same length of a branch of the plant
Volume of NaHCO3 and Water
Having more concentration of CO2 will change the rate of reaction
Adding the same volume of both substances

Method:
1. Place all the equipment as instructed on diagram #1, leaving the plants aside
2. Measure length of the plant so its exact value as the other one also has only one branch.
3. Also have the same concentration on both CO2 in both adding the same solution(NaHCO3)
4. Placed the branch in the cold/hot water for 5 min to see reaction and close it with oxygen sensors on top
5. After 5 min take recording of the total oxygen produce to compare the temperature effect on the reaction
6. Then remove the branches and clean equipment.