Pond skaters and surface tension at Campfield Marsh

Mrs B spotted this little bug on a pond at Campfield Marsh. One important reason for their ability to walk on water is surface tension. Water molecules have a kind of charge separation that makes one end positive and the other end negative.This means that the molecules attract each other. A molecule in the middle of the liquid is pulled equally in all directions. At the surface, there is nothing above to pull the molecules upwards so there is a stronger net force downwards. This pulling inwards creates surface tension. Provided the surface tension is greater than forces due to the insect, it won't penetrate the surface. Hairs on the legs increases its surface area thus reducing the force per unit area so that at any given point, the surface tension will not be beaten.