The surface tension of water is its ability to let items float on its surface. Tension on the surface forms because of the cohesive bond between the hydrogen atoms in a water molecule. This is what allows small insects like water gliders to not sink as they hop across the water.
In our experiment, we could careully float paperclips on the surface of the water. We couldn't get them to float on soapy water.
pretend this is a paperclip
Surface tension is caused because of the different strength of the hydrogen bonds at the surface.
Water molecules like to stick together. However, because of the air molecules close the surface, there are less water molecules at the top of water than in the middle. This makes a layer of stronger bonds between themolecules that actually do come in contact on the surface.
This could be seen in the experiment with the paper clips, because as soon as a paper clip broke the bonds of the surface molecules, the bonds could no longer help it float and it sunk through the weaker bonds of the lower molecules.