Farhan.Hanif93 (Offline)  

Salaams farhan can you give me some tips on how to revise maths

Thank you, that's very amiable of you

Very encourage puns as well, 10/10, or should I say, S,S.

Hehe.

Yes, I've achieved 76-79% and 84% on two of the past papers.

Did you positively rep me? If you did, thank you. I think someone negged me for surrendering to Cambridge mathematicians?

Many thanks Farhan - I have never felt this happy! I hope all is well with you - hopefully we'll meet next year! (oh and congrats on being a mod - it looks cool)

Congrats on turning purple. No great surprise, and well deserved.

You've joined the dark side Welcome and congrats

Hello, can I get some help with some Biology please


The whole point of our experiment was to answer the following question: "How does the wavelength of light affect the rate of photosynthesis?". We used five different coloured filters- purple,blue, orange, green and red. DCPIP ( coloured dye) was used in this experiment and it was acting like the NADP. It is blue- green when oxidised, but when it is reduced it becomes green.

This is an outline of what the experiment consisted of:
1) Take some leaf extract into a capillary tube and use this as your "standard".
2) Then add DCPIP dye into the leaf extract suspension and mix together. Immediately cover this beaker containing the two solutions with a piece of foil.
3) Take some of this mixture into a capillary tube and then place next to the 'Standard' onto a white tile. Immediately place the purple filter over both of these capillary tubes so both of them are covered.
4) Switch on the lamp and start the timer immediately. Record the time taken for the colour of solution in the other capillary tube to go the same colour (that it from blue green to green) as in the 'standard tube'. Lift the filter briefly to find out if the colour change has occurred.
5) Repeat this with the other filters too.




Now my questions to you are?

a) Please can you help me identify some limitations with this expt?
b) I got my results of the expt as this: purple filter took least time to turn green, then red filter, then orange, then blue and finally green. Does my results look OK to you?
c) Please can you provide a reason for these results? What conclusion can we draw from these results?
d) How could we ensure validity with this experiment?
e) In this how can the effect of uncontrollable factors be minimised?
f) How can we make the results reliable?
g) What was the purpose of the standard?
h)What things should you have kept constant in this expt?

Thank you if you could give me some ideas for these please.

Killjoy... It's actually the perfection medal, stealing my glory telling people it's "unfrigginbelievable!". Halo nub