| a chemical mixture often used to keep internal combustion engines from overheating and destroying themseves. the main ingredient is usually propylene glycol or ethylene glycol, both of which are toxic, altho antifreeze is also available in low-tox formulations.
a 50% solution of water and antifreeze is reccomended to fill your coolant system. water is a better coolant than straight antifreeze, but has the nasty habit of freezing in cold weather. not only is it a piss poor antifreeze if it does freeze under "normal" operating conditions, but this will also destroy your liquid cooled internal combustion engine, as water expands when it freezes. antifreeze doesn't cool quite as well as water, but it has rust inhibiting chemicals in it. it also doesn't freeze (you know, since it's antifreeze) or boil as easily as water, so it can be used in more extreme temperature conditions. a 50% aqueous solution of antifreeze provides the best of both worlds for most driving conditions.
kids and pets are prone to drink antifreeze if it is left lying about - it's bright and pretty. rumor has it that it is sweet, but i can assure you that it most certainly is not. | 
