1. Why do earthworms come out of the soil when it rains? By Callum Timpany

2. The scientific reason Why do Earthworms come out in the RainEarthworms need moist environment for their survival. They mainly live underground to avoid sunlight, as sunlight removes the moisture from their skin. They would die quickly if remained exposed to sunlight for a long time. Earthworms need a moist environment for diffusion of gases through their skin. They are often seen above the ground after a heavy rain. There are many theories about this behaviour of earthworms. One opinion is that the amount of oxygen dissolved in water is less than that in the air. So, earthworms come above ground when their burrows get filled with rainwater. However, if sufficient amount of oxygen is dissolved in the water, they can live underwater for many days.Another supposition is that the humidity after rain is high, and therefore the earthworms come out as the high humidity protects their skin from dehydration. Besides, they can also move faster on the moist surface, and therefore reach new places for populating. Another reason for coming above ground may be the fact that due to respiratory activities of organisms living underground, the level of carbon dioxide increases. This carbon dioxide forms carbonic acid with rain water. So, to avoid such a harmful acidic environment, they come out to the surface.To sum up, shortage of oxygen in the burrows due to heavy rain, formation of carbonic acid and mating are some of the possible reasons for which earthworms come out from the burrows after rain. Whatever may be the exact reason, they loosen the soil structure by their activities of coming up and down the burrows, which facilitates aeration of soil. Besides, they are also loved, especially by farmers, for increasing soil fertility by decomposing organic matter and converting them into essential nutrients required by plants.

3. Simplified Earthworms need a moist environment to survive. One theory of why the surface during rain is that the burrows that they live in flood with the rainwater, this forces them to head to the surface to avoid drowning.

4. Continued... Another theory that scientists believe is that because humidity is high after it has been raining the worms surface as this protects their skin. The last theory is the fact that there is a high amount of carbon dioxide in the earth and when this is mixed with rainwater it makes carbonic acid .

5. Continued... The worms help farmers when they surface, they do this by increase soil fertility by decomposing organic matter and turning them into nutrients for plants.