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GCSE Biology Osmosis Coursework watch

1. For my coursework I have to investigate osmosis in potato cells. I need help with my prediction and factors that affect the osmosis. Can anyone give me any help please?
2. Oh wow i remember this investigation!!

It's awful!! Hehe in a really monotonous type way

R U doing it with different sugar solutions?? If u r then basically wot ur doing is putting bits of potato in different concentrations and if the solution is too strong then the water will flow out of the potato and it will shrink and if the solution has too low a water potential then water will flow into the potato and it will grow!

And it's about 10%... but that's assuming that you use the same solution so u really oughta do prelims!
3. (Original post by Bekaboo)
Oh wow i remember this investigation!!

It's awful!! Hehe in a really monotonous type way

R U doing it with different sugar solutions?? If u r then basically wot ur doing is putting bits of potato in different concentrations and if the solution is too strong then the water will flow out of the potato and it will shrink and if the solution has too low a water potential then water will flow into the potato and it will grow!

And it's about 10%... but that's assuming that you use the same solution so u really oughta do prelims!
I think that we will be using salt solution.
4. same thing really. Umm your predictions should be about them increasing in mass (or length) with the pure water then talk about some water potential stuff. And well the opposite for high concentrations of salt solutions.
As for errors talk about measuring errors (parralax, evaporation etc...) meaning your solution aren't exact. Blame the instruments is always a good one especially if you're doing length. And then i put various other things like the fact that potato chips were wet when i weighed them.
Hope that helps, its the worst coursework really
5. i rememba this!!!
the onli purpose of the premliminary work is that it allows you decide what is the best way to find osmotic changes.(i did weighin for the real one). Measuring it tells you to rethink the way your gona monitor osmotic change as measurin is tedious and inaccurate and hard to notice a change...
its reali important you mention how the preliminary work helps 2 shape your eventual main exp. thats y u use weighin scales as it is easier etc.. blah.blah,blah.. soz if its written randomly as im very tired...!
6. So would it be right for me to say in my prediction that the higher the concentration of salt solution the bigger the mass of the potato chip will be, and that the lower the concentration of salt solution, the smaller the mass the of the potato chip will be.
7. Okay, so now I really need help with writing up my preliminary investigation plan. Any takers?
8. How much time would you suggest for me to leave the potato chips for my preliminary investigation?
9. (Original post by Melanie47)
How much time would you suggest for me to leave the potato chips for my preliminary investigation?

try taking readings every 30 seconds for five minuties. This will be a bit too long for some of the faster experiements but doing it at this time period will mean you can get all of the slower experiemtents allowing you to produce some nice graphs but to be honest coz it's only perliminary it doesn't matter how many readings - long a time period you use - that's what you want to find. But 30seconds for 5 minuites is a good place to start.
10. (Original post by gaming_goddess)
try taking readings every 30 seconds for five minuties. This will be a bit too long for some of the faster experiements but doing it at this time period will mean you can get all of the slower experiemtents allowing you to produce some nice graphs but to be honest coz it's only perliminary it doesn't matter how many readings - long a time period you use - that's what you want to find. But 30seconds for 5 minuites is a good place to start.
Thanks for that! I had no idea where to start with the timescale, so that was a real help.
11. (Original post by Melanie47)
For my coursework I have to investigate osmosis in potato cells. I need help with my prediction and factors that affect the osmosis. Can anyone give me any help please?
i remember doing this!.....it was dreadful!!

factors that affect it would be size and weight of potato.....concentration of sugar/salt solution and time the potatoes are kept in the water
12. (Original post by Saf!)
i remember doing this!.....it was dreadful!!

factors that affect it would be size and weight of potato.....concentration of sugar/salt solution and time the potatoes are kept in the water
13. (Original post by Melanie47)
oh.....(i have to say i can't really remember but i'll give it a shot just for you!)

if the potatoes are differnt sizes then more water will enter the bigger potatoes and less into the smaller ones and hence the test will be unfair..... if you start with potatoes of the same weight it will be easier for you to compare results etc

Prediction:

in pure water the potato will swell up cos water will enter into the cells, by osmosis. this is because water goes from a high concentration to a low concentration. the potato is rich in sugars so the water will go into it

in a sugary/salty solution the potato will shrink as the water inside the cells will come out into the beaker

hpoe that helps! (and hope it makes sense too!)
14. (Original post by Saf!)
oh.....(i have to say i can't really remember but i'll give it a shot just for you!)

if the potatoes are differnt sizes then more water will enter the bigger potatoes and less into the smaller ones and hence the test will be unfair..... if you start with potatoes of the same weight it will be easier for you to compare results etc

Prediction:

in pure water the potato will swell up cos water will enter into the cells, by osmosis. this is because water goes from a high concentration to a low concentration. the potato is rich in sugars so the water will go into it

in a sugary/salty solution the potato will shrink as the water inside the cells will come out into the beaker

hpoe that helps! (and hope it makes sense too!)
Oh... when I said tell me about it, it was in reference to you saying the coursework was dreadful actually

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