Key Stage 4 Photosynthesis Investigation

The aim is to find out weather light intensity affects the rate of photosynthesis.

Prediction + Theory/Hypothesis:

I predict that light intsinty (brightness) does affect the rate of photosynthesis. As the intensity gets higher I expect that the rate of photosynthesis will increase, until it can’t increase any more dew to limiting factors such as Co2 levels + temperature

Plan/Method:

1. Set up all equipment (see diagram).

2. Set the voltage on the power pack and then turn on the power pack.

3. Time for 1 min, then, when 1 min is up, turn off the power pack.

4. Use the micro-burette and record the results.

5. Do step 2-3-4 until you reach the maximum voltage (that you want)

Equipment List:

* Glass block

* Power pack

* Light bulb

* Glass beaker

* Water (100ml)

* Pond weed

* Micro-burette

Diagram:

Results:

Voltage (volts)

Exp. 1 Oxygen

Collected (cm3)

Exp. 2 Oxygen collected (cm3)

Exp. 3 Oxygen collected (cm3)

4

6.25

25.15

15.70

6

25.14

30.15

20.55

8

62.70

100.48

40.67

10

75.45

125.70

55.85

12

100.20

75.60

85.75

Conclusion:

From my results I can conclude that my prediction was correct. My prediction about limiting factors such as Co2 level + temperature were also correct.

Evaluation:

I think that my method was suitable for this investigation as you can see from my results. I think that my investigation supports my results and my conclusion