A Shallow plastic box measuring 25cm x 30cm with a plastic separator down the centre was used to contain the soil samples. The same sample of soil was used but additional tap water was added to make the wet sample.
The separator was level with the soil so that there was not an obstacle in the pathway of the worms when they were moving around the container.
Six worms of varying lengths and thickness were then placed in the centre of the box. They were all collected from a 1m of the garden and placed in a jar.
The start time was recorded and after 15 minute intervals the numbers of worms in each half of the container were counted.
Newspaper was placed under the container in case any of the worms escaped.
My hands were also thoroughly washed after handling the worms. Both containers that the worms came in contact with were disposed of after the experiment.
Results Table
Time in Mins No. of worms on dry soil No. of worms on flat soil
15 3 3
30 2 4
60 1 3
75 4 2
90 2 4
TOTAL 12 16
Observations
The worms moved relatively slowly hence the 15 minute intervals between each result. The head end of the worm became raised and moved around quite rapidly and at times probed the soil as if it was foraging for something.
When one of the worms found the wet soil it remained there for the whole of the experiment and did not move.
Results and Discussion
More worms were observed in the wet section of the soil than the dry in the ratio 12:16.
The hypothesis that the worms would prefer the wet soil was supported, although at times it was difficult to be 100% accurate as the worms were quite long and had a larger length of their body in the wet than the dry soil.
Conclusion
The hypothesis was supported, I based my decision on evidence that I observed in the past i.e. on rainy days worms come to the surface of the soil.
This may be because the worms can move better in wet damp soil or there may be more things about to eat in wet conditions or it maybe that the worms do not like to have their burrow flooded out.
Further Work
More experiments could be carried out possibly with a larger amount of worms over a bigger soil sample or continue the experiment over a longer period of time.
The equipment used could also be more sophisticated.
