How Does Light Affect the Rate of Photosynthesis?

1949 Words Oct 25th, 1999 8 Pages
Biology Investigation

Problem: How does light affect the rate of Photosynthesis?

The Plan

In my experiment I am going to see how light affects the rate of photosynthesis. To do this experiment I am going to set up the apparatus as shown in figure 1.

The apparatus I am going to use are the following: -

1 Tripod
1 300ml Beaker
1 Boiling Tube
1 Clamp Stand
1 Boss
1 Ring Binder
1 Lamp
1 1 Metre Ruler
1 Thermometer
1 Stop Clock

To do the experiment I will set up the apparatus first. I will firstly place the tripod on top of the base of the clamp stand and fill the 300ml beaker with 250ml of water to create the water bath. I will place the boss in the middle of the bar on the clamp stand and place the clamp in the boss. I
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Distance 3 4 Average
10cm 70 64 67
20cm 56 52 54
30cm 29 28 28.5
40cm 15 15 15
50cm 8 7 7.5

These are the second set of results done with fair testing. There are no anomalies in these results because all the safeguards were down properly.

I have tried to make my readings as clear and accurate as I could have possibly. I had made sure it was a fair test by adding Sodium Bicarbonate in the boiling tube to enrich the water with Carbon Dioxide so more Oxygen bubbles would be produced. I also made sure that the volumes of the water in the 300ml beaker and in the boiling tube the same so the temperature could stay the same, as that would affect the rate of photosynthesis. I put a ring binder around the clamp stand so that it would block ‘foreign’ light that would be collected by the pondweed and continue photosynthesis after I had switched of the lamp. I constantly checked the temperature of the boiling tube and the beaker so it wouldn’t affect the rate of photosynthesis. I used a thermometer to check the temperature and I used a water bath to regulate the temperature of the boiling tube. I continuously used the same pondweed in all of my experiments so that the amount of chlorophyll would stay the same and the amount of Oxygen produced would also stay the same.

I believe my method was not really suitable because there were a few problems with it. I chose to count the