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1. For a test, I had to carry out an experiment in which I placed pondweed in boiling tubes and wrapped each boiling tube in a coloured filter to see if changing the wavelength of light changed the rate of photosynthesis. we then counted the number of oxygen bubbles produced for the rate.

what would be an area of uncertainty in this investigation and could you explain it please? also, how would you know if your results were reproducible?
many thanks.
2. (Original post by Bertybassett)
For a test, I had to carry out an experiment in which I placed pondweed in boiling tubes and wrapped each boiling tube in a coloured filter to see if changing the wavelength of light changed the rate of photosynthesis. we then counted the number of oxygen bubbles produced for the rate.

what would be an area of uncertainty in this investigation and could you explain it please? also, how would you know if your results were reproducible?
many thanks.
What were you trying to find out and is there a relevant equation?Uncertainties are complex and depend on the readings you got, the resolution of the measuring equipment you used etc.
Overall uncertainty of your result combines these % uncertainties depending on the equation relating all your variables together

Reproducible results can be replicated by another with same set-up/equipment - usually classmates and if the results are similar enough (can't remember what margin but something like <+or- 15% difference) then they are reproducible

Hope this helps and feel free to ask questions.
Cheese
3. (Original post by CheeseIsVeg)
What were you trying to find out and is there a relevant equation?Uncertainties are complex and depend on the readings you got, the resolution of the measuring equipment you used etc.
Overall uncertainty of your result combines these % uncertainties depending on the equation relating all your variables together

Reproducible results can be replicated by another with same set-up/equipment - usually classmates and if the results are similar enough (can't remember what margin but something like <+or- 15% difference) then they are reproducible

Hope this helps and feel free to ask questions.
Cheese
my hypothesis is 'a change in the wavelength of light will change the number of bubbles produced per minute', so i am trying to find out whether changing the wavelenght of light (or coloured filter around the light) changes the rate of photosynthesis. we then would turn on a light 25cm away. for gcse level i dont know if we have a given equation as my teacher hasnt said anything about it.
because there are other factors that affect the rate of photosynthesis (co2, light intensity, temperature) would any of these factors create uncertainties e.g. the investigation could be done by a window with the sun coming in/out so this could increase/decrease the temperature/light intensity (both limiting factors of photosynthesis) which would affect the rate of photosynthesis and so make the results less accurate?
any help would be much appreciated.
4. (Original post by CheeseIsVeg)
What were you trying to find out and is there a relevant equation?Uncertainties are complex and depend on the readings you got, the resolution of the measuring equipment you used etc.
Overall uncertainty of your result combines these % uncertainties depending on the equation relating all your variables together

Reproducible results can be replicated by another with same set-up/equipment - usually classmates and if the results are similar enough (can't remember what margin but something like <+or- 15% difference) then they are reproducible

Hope this helps and feel free to ask questions.
Cheese
also, would i need a control for this investigation e.g. using different coloured filters around each tube and then having one tube without a filter to act as a control. would i need to do this and if so what would be the point in doing this.
thanks
5. (Original post by Bertybassett)
my hypothesis is 'a change in the wavelength of light will change the number of bubbles produced per minute', so i am trying to find out whether changing the wavelenght of light (or coloured filter around the light) changes the rate of photosynthesis. we then would turn on a light 25cm away. for gcse level i dont know if we have a given equation as my teacher hasnt said anything about it.
because there are other factors that affect the rate of photosynthesis (co2, light intensity, temperature) would any of these factors create uncertainties e.g. the investigation could be done by a window with the sun coming in/out so this could increase/decrease the temperature/light intensity (both limiting factors of photosynthesis) which would affect the rate of photosynthesis and so make the results less accurate?
any help would be much appreciated.
Hmmm ask your teacher, here I do not know enough info to calculate an uncertainty, so that means you need info from your teacher I guess That sounds about right tho However biology isn't my forte (at all lol) Physics/Chemistry = life
So give it a check with another user/teacher/classmate/human?

(Original post by Bertybassett)
also, would i need a control for this investigation e.g. using different coloured filters around each tube and then having one tube without a filter to act as a control. would i need to do this and if so what would be the point in doing this.
thanks
ditto above, not sure
Usually it'd be safe to - in order to check there is a trend in results and its not just a fluke (random error) each time
but yeah, definitely give it a check with another individual as well

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