Pat, Van Der Waals forces, IIRC, are also known as "induced dipole" forces. Here's the long explanation I'll give, since Wikipedia does not address this issue from a metalworker's perspective (but it's still worth reading):
An atom, to oversimplify, can be thought of as a negatively charged cloud of electrons surrounding a positively charged, massive core of protons and neutrons.
Now, ignore the nucleus (chemistry, the area which dipoles fall under, involves only electrons, with exceptions). The electrons do not "orbit" the nucleus of the atom, per se. Instead, they fly about however they damn please, and if you were to average this random path out (and yes, it is completely random, according to Heisenberg), you would get a roughly spherical area which the electrons confined themselves to. This is because the electrons want to get as close as possible to the strongest positive charge in the area, which is the nucleus (check out the "Pauli exclusion principle" if you want to know why they don't just bunch up right in the center).
So, obviously, the electrons closer to the nucleus will feel a stronger attraction to it. Thus, they will have marginally less freedom, and will create a more spherical cloud than electrons farther out. A larger atom, however, will have a larger electron cloud. The electrons farther out will feel less attraction to the nucleus, and thus will be more free to devate from a spherical electron cloud.
Now, what if these electrons should decide to spend slightly more time on one side of the atom than the other? You would have a roughly elliptical electron cloud, and the side that had more electrons would be slightly more negatively charged than the other side. This is called a "dipole". The charge of the one atom then influences the electrons of neighboring atoms to create another dipole. This can enduce a weak dipole effect in the every atom present.
That induced dipole is the Van Der Waal force. It is most commonly studied in noble gasses (such as Argon, Neon, Krypton, and Xenon), and is used to explain why the more massive noble gasses (such as krypton and radon) are easier to condense into liquids than the lighter ones (such as helium and neon). Induced dipole forces apply to jo blocks because the atoms in one jo block get dipoles in them. They are close enough to the other Jo blocks that they induce dipoles in those jo blocks. This creates a strong attraction. Imagine stacked magnets, and you've got the general idea. .
Note, I have only addressed induced dipole forces on the atomic level. I have entirely ignored dipoles on the molecular level because, due to the nature of metallic bonds, dipole forces occue in metals at an atomic, not molecular level. The above account has a pile of holes, which, if you want to fill, I reccomend reading the wikipedia entries on "dipoles", "electronegativity", "electron orbitals", and "metallic bonds".
Trig and calc are useful when you know them. I only appreciated trig's use when I learned it. i still don't know enough calc to claim I fully appreciate its use, but i ave no doubt that I will find uses for it when I do learn it.
Edit: Damn, this's a long post. Sorry. Me wonders if anyone will read it, cuz in retrospect, I wouldn't.