You are Here: Home >< GCSEs

# Science investigation help!

Announcements Posted on
Would YOU be put off a uni with a high crime rate? First 50 to have their say get a £5 Amazon voucher! 27-10-2016
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

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: October 8, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### University open days

Is it worth going? Find out here

Poll
Useful resources

## Study tools

### Essay expert

Learn to write like a pro with our ultimate essay guide.

See where you can apply with our uni match tool

### Make study resources

Create all the resources you need to get the grades.

### Create your own Study Plan

Organise all your homework and exams so you never miss another deadline.

### Resources by subject

From flashcards to mind maps; there's everything you need for all of your GCSE subjects.

### Find past papers

100s of GCSE past papers for all your subjects at your fingertips.