Light Intensity Effect On The Rate Of Photosyntheis Experiment

Question 1

What is step 1 of the experiment and why is it done? (2 points)

Answer 1

1- set up a test tube rack containing a boiling tube 10cm away from the light source

• 10 cm is the first distance in the range of the independent variable

Question 2

What is the second step of this experiment of testing the effect of light intensity on the rate of photosynthesis?

Answer 2

2- fill the boiling tube with sodium hydrogen carbonate solution

• the solution provides carbon dioxide that the plant needs for photosynthesis

Question 3

What is the third step in the experiment for testing the effect light intensity has on he rate of photosynthesis?

Answer 3

3- put the piece of pondweed into the boiling tube with the cut end at top+ gentle push the pondweed down with glass rod

• the cut ends need to be underwater so that the bubbles can be seen coming off it

Question 4

What is the fourth step of the experiment and why is it done? (2 points)

Answer 4

4) leave boiling tube for 5 minutes

• plant needs to be photosynthesising at a steady rate before measurements start

Question 5

What is the fifth step of this experiment and why is it done? (2 points)

Answer 5

5) start stop watch and count number of bubbles produced in one minute

• this is the dependent variable

Question 6

What is the final step in this experiment and why? (3 points)

Answer 6

• repeat steps above with test tube rack+ boiling tube at different distances from the light
  (20 cm, 30cm, 40, 50cm)
• to test the hypothesis
• wait to allow the rate to stabilise at the new light intensity each time