Why is a water drop round when it is in the air and what force causes
it to form this sphere.  Also if you put a drop on wax paper and on
plastic and on paper it forms different drop shapes.  Why is this and
what force causes this.  Why is a bubble round.

Sphere = minimum surface area for a particular volume
Shape of drop depends on interaction between water and surface. More
hydrophilic surfaces will produce 'flatter' drops due to polar (esp.
hydrogen bond) interactions

You're right, chemical bonds between molecules give rise to surface
tension. Water molecules readily form hydrogen bonds with one another,
lowering their energy relative to an isolated water molecule in air. A
water molecule at the air-water interface on the edge of a droplet has
fewer hydrogen bonds and is thus slightly higher in energy than those
in the interior. Thus there is an energy cost per unit area of
interface, and this is the surface tension. The shape that best
minimizes surface area also minimizes the total energy, and that
optimal shape is a sphere.

The surface of a bubble is a thin soap film that responds elastically
when stretched or bent. (Stretch it too far and it pops, of course.)
For a fixed enclosed volume of air, a free bubble will always form a
sphere, again to minimize its total surface area.

Unlike a liquid, a crystal has an underlying structural motif that
repeats again and again. Slicing a perfect crystal along different
planes exposes surfaces with a variety of different structures, and
the local surface tension (e.g. in air, or in water or another
solvent) can vary significantly from one surface to another. Thus a
crystal can develop flat facets and sharp corners, stable structures
that are not seen in water or free soap bubbles.

The shape of water droplets on wax paper, and paticularly the angle of
contact, is determined by the relative surface tension between
water/paper, water/air, and air/paper. I'll leave discussion of that
topic for the guy/gal who wants to earn $3.50.

The intermolecular forces in a liquid are far greater than that of a
gas, which is the reason why they are in two different states. To
eloborate on that, the attractive force between water molecules is
much greater than the attractive force between air molecules. In water
the most dominat force is the hydogen bond of the order of 5 kcal per
avagadro number of molecules. But in other liquids with out such
strong bonds the Vandervalls forces are the most dominant. In air the
vandervals forces are insignificant, which is the reason why the
molecules fly about randomly, as if they dont see each other untill
they collide. Given this senario, a water molecule on the surface of a
drop experiences a strong force from the bulk of water and almost none
form the air molecules. Result, there is a net force on the surface
molecules directed to the center of the water molecule, to be accurate
towards the rest of the molecules. Ofcourse the forces will be
balanced eventually by the repulsive forces between the water molecues
when they try to get too close.

So far I have established the existence of a force on the surface that
is directed into the bulk of the water drop. To see why it is a
sphere, Imagine any other configuration, and u will see that the
internal forces will be balanced only if the inward force from
different parts of the surface are equal.

Notice the implicit use of Newtons second law, when equilibrium
condition was used.

If u didn't buy my argument in the second paragraph,you were really
thinking, the sphere is only one stable configuration in which water
can exist, A buble is an unstable configuration in which forces can be
balanced. since the air is trapped there is no way for the air
molecules to force ther way out, the water molecules experience a net
inward force, this time into the rim, and going by the internal forces
argument, again it has to be a sphere.

Through out this argument, I have not included gravity to keep it
simple. But it should not pose a problem, given the fact that the
water is falling freely, which means it has been included in the force
balance.

Coming to the other question abut shapes on different papers ,

May I ask how they are different ?
I haven't seen them before.