In my experiment I am testing whether the woodlice prefer the environment to be wet or dry. I predict that they will prefer it wet rather than dry. I think this because when you find them in the wild, they are in dark damp places like under big rocks or a log.
Method
First of all in my experiment I will set up a ‘choice chamber’ with wet cotton wool under one side and keeping it dry on the other. I will putt a bit of netting over the top so the woodlice can walk over it. We chose to use 15 woodlice because the more you use it makes it less likely for the results to be due to chance. There is a problem with the woodlice clumping up with each other (this is one of the things they naturally do when the get close to something or each other). It may affect the distribution but there isn’t really anything I can do to solve the problem.
Diagram
I will take down the results every minute for twenty minutes to put in a graph. I am doing it for twenty minutes because it will enable me to do a chi2 (χ 2) at the end of the experiment. The chi2 test is a test that checks to see if your results are reliable and not just due to chance. For example you, you could flip five heads in a row on a coin but if you did it fifty times it would balance out. The chi2 test helps find occasions like this.
Results
The results show that the wood lice preferred the wet environment to the dry, This may be easier to see in a graph.
Graph
The results do say that that the woodlice prefer it in a wet environment
but this could be due to chance. To make sure its not due to chance I shall do the chi² test.
According to the X² distribution for 20 woodlice for a one in twenty chance of the results being due to chance X² should be above 31.41; my total is well above that. For a one in hundred chance of the results being due to chance its 37.57. Mine is just under sixty so my results are almost definatly not due to chance at all. Woodlice prefer their environment to be wet. They prefer to live in a wet environment because they are permeable to water vapor they need to be in wet places to get their water supply. That is why they are found under big rocks and under logs in the wild; they are both damp places.
Evaluation
Overall; I think the experiment went very well. There weren’t really any problems at all. I think the way we obtained our results worked very well. The results we got were very good as well there were no really strange results compared with the rest of them. I don’t think I would change the way we got our results because there isn’t really another way to do it. I think our results were very reliable as the chi² test proved that they were not due to chance, they are definatly sufficient to support the conclusion I have made. The only problem we did have with the test was getting the woodlice in the choice chamber. In the end we just decided to open the lid throw them in and hope that none of them would escape; and they didn’t.