Even if you don't think you do, you already know plenty about commodities. Want us to prove it? No problem.

What makes oil produced in Saudi Arabia different from oil exported from Nigeria? It's the same thing that makes the corn you ate at last summer¿s barbecue different from the corn used to produce ethanol. Stumped? Well, don't feel bad, it's a trick question. The answer? Absolutely nothing. Corn is corn no matter where it comes from -- just as wheat is wheat and natural gas is -- right! -- natural gas. (Though the quality may differ, the make-up is uniform.)

So, in less elaborate terms, corn and oil (and all other commodities) are homogenous goods that can be processed, resold and more often than not, used as an input to the production of other goods or services. These goods are traded on a commodity exchange, thus setting the price-per-barrel (or other metric unit) used to value them.

Now pay attention, here's a question that indeed does have an answer: What is the difference between a commodity and a stock? While a stock can tank and become worthless, a commodity cannot have its value be wiped to zero. One other difference: Most commodities are traded in futures, meaning traders buy and sell where they think the price of a product will be at a certain point in the future. Stocks trade based on the value of the underlying company at that point in time.