Water

We did a lab in class. So what we did was to put water onto a coin drop by drop until the surface of the coin could not hold more water. When the water was about to "collapse," it was in the shape of an arch, like this:

The reason why water can stay on the coin is because the water molecules are sticked together by hydrogen bonds(cohesion). It has the shape of an arch because each water molecule has the shape of an arch, and when they stick together, they make archs, too. If you poke the arch made by water with a toothpick, you will find out that instead of bending in, the water arch "climbs" up the toothpick. This is caused by the adhesion of water. Because of the difference of charges, water molecules are attracted to the toothpick, therefore, "climbs" up. This is also how plants absorb water. When water evaporates from leaves, more water will be pulled up by adhesion.

Water has a higher heat capacity, which means that a certain amount of water can absorb or release more heat in a certain amount of time than most other matters. This is why the climate is milder at seaside.
The evaporation of water absorbs heat, so human and animals sweat when they feel hot.
Water evaporates faster when there's lower pressure, higher temperature and bigger area exposed to air.

I think that's all...