Money is sometimes also referred to as liquid, hence liquidation sale before a place go out for business - quick way to get some cash in, or how liquid your investment is, etc. Why money is also referred to as liquid, I'm not sure (too lazy to google this one), but ironically, money has other properties that's identical to those of true liquid.
I remember in my science class when they explained the difference between the three states: solid, liquid, and gas. Think of solid as a wooden cube, it will neither change shape nor compress; air, as we all know, is highly compressable, up to a certain point; liquid, however, is the strangest among the three, it's highly malleable, you can pour it into containers of any shape, but it actually won't compress at all, as opposed to contrary belief. Think of water inside a plunger, if the outlet it block, no matter how hard you press, it won't give.
So here's a very simple concept for all ye American folks who are in debt up to their eyeballs (the one's being laid off due to the poor economy notwithstanding), if you monthly income is $2,000, and your expenses -- rent, food, car insurance, cell phone bill, gas, etc -- adds up to exactly $2,000, no, you do NOT have extra anywhere for even a $4 item. You cannot just squeeze it out of thin air, unless you cut expenses else where.
That is a simple concept that mysterious escape lots. The fact that the concept escapes lots eludes me....