Water is the only substance that naturally occurs in three forms, liquid, solid, and gas. All life as we know is dependent on water. H2O is the molecule of water that has two hydrogen atoms that are positive, and one oxygen atom that is negative. Because of polarity all water molecules are attracted to each other and stick creating hydrogen bonds, the positive pole around the hydrogen atom bond to the negative pole of negative atom of a different molecule.
A property results is high cohesion. Cohesion is the attraction of two like things, in this case water molecules. When a pebble is tossed into water, the water bounces in waves but doesn't separate into individual molecules. The hydrogen bonds continue to pull individual molecule, the pull is so strong that it stays together in small pools or droplets. This can be seen on leaves after in rains, helping the plant get nutrients.
Adhesion is is the attraction between two different substances, the water spreads out because the adhesion forces are stronger than the cohesion force. In pants the water sticks to the xylem which helps it go up the plant.
Water forms a dome shape on top of a penny because the hydrogen bonds continue to pull individual molecule, the pull is so strong that it stays together, because the water molecule is attracted to the similar substance.
Soap is not similar to the water molecule, so when the penny was first dipped in soap the droplets of water could only stay together for a limited amount of time.
Salt is a polar substance because it can easily dissolve in water which is also a polar substance, cooking oil on the other hand isn't because after you stir it still is not completely dissolved and most remains on the top of the surface.