Diagram
Test Tube Lamp
Gas bubbles
Beaker
Funnel
Pondweed
By changing the distance of the lamp between the beaker it will have the effect of showing different results of the rate of photosynthesis. If I use this it will show me how much light is captured by the chlorophyll. To see if more is collected if nearer or further and also for if less is collected if it is nearer or further away. Which will lead to how much oxygen is produced.
I think the nearer the Lamp is to the beaker will have a greater effect on the rate of photosynthesis as it will become more powerful. I think this because the closer the lamp the more light rays will go towards the beaker and create more oxygen bubbles through the process.
To choose the lamp as to find out what occurs when you try to control the rate of photosynthesis that I will have to be careful. To be safe I will have to make sure I don’t spill the liquid if I do there could be a dangerous situation with the lamp as in electric shock, which can have serious effects.
The equipment I will use is clearly shown in the diagram but will first have to set the apparatus up. Then I will start timing the amount of bubbles that comes out in a minute and then write it down the amount then put the lamp closer. And repeat from the lamp off to 100 cm to 50 cm to 30 cm to 10 cm. This will give me a fair amount of results for the investigation. But I will do the experiment four times to makes sure my results are correct and also to see if I have done something wrong.
Results
Number of gas bubbles / minute
Distance of lamp
From apparatus Group A Group B Group C Group D Average
Lamp off 0 0 0 0 0
100 cm 0 2 11 0 3
50 cm 19 39 26 10 24
30 cm 41 60 53 12 42
10 cm 59 over 100 79 60 over 75
I have also taken an average to be more scientific as it is not always good having one group of results that is always better so I can see if something has gone wrong.
100
80
60
40
20
0 10 20 30 40 50 60 70 80 90 100 Lamp off
Distance from the beaker (cm)
My conclusion is that the results I have all seem to be quite similar meaning that my experiments didn’t have a flaw. But also from what I predicted was also correct to see that the nearer the lamp got the more gas bubbles were produced. I see a clear factor that links the distance of the lamp to the beaker. This is that the nearer the lamp was the more energy the plant would be getting. This would effect the rate by giving the molecules more energy to move around freely. While doing this it would have the effect that the reaction would happen quicker because the molecules are moving around causing more particle collisions which causes this reaction to take place. Making the rate of photosynthesis increase to a higher rate when this occurs.
My evaluation is that the experiment of the investigation seems to go quite well. Except from a few odd calculations in Group d it all went well. This is what I would of hoped to achieve in the time and resources we had. If I were going to do it again I would think of an another way of calculating the amount of bubbles. As if I blinked or itched my eye while doing the experiment I could have missed very important information which could come in helpful to calculate the rate. Using different scientific equipment could change this or just more than one watches the bubbles so you have a second view on it. I feel pleased with the investigation and it seems to have gone reasonable well by using good, fair and safe results.
