How does a water boatman swim?
If you want to try an experiment to test how strong the “skin” of water really is, try making yourself a cup of your favourite drink (tea for example). With the cup full, take a teaspoon and try to balance it on the rim of the cup so that the spoon end is floating in the liquid and the handle is horizontal (ish). It might take a bit of practice to get the spoons centre of gravity in exactly the right spot, but when you do you will notice that you can slowly push the spoon so that more of its weight is resting on top of the liquid. Eventually of course, the spoon will sink. This happens when it displaces a mass that is greater than its own. The same applies to water-boatmen, and all other creatures that can walk on water.
