Antifreeze is added to the cooling system of a car so that the water within it does not form ice crystals. Cars need to function in all sorts of temperatures, and although water is useful in holding heat, it doesn't work as well in the cold. Cars would be pretty useless if they couldn't be used in temperatures below 0C!
The freezing point of water is lowered when another substance is dissolved within it. To make antifreeze, a substance called ethylene glycol is mixed with water, and it is this we then pour into our cars' radiators. Ethylene glycol is used for a number of reasons.
- First, ethylene glycol is easily dissolved in water, and doesn't crystallize at lower temperatures.
- Second, it doesn't react chemically with anything else within the automobile cooling system.
- Third, it is cheap to process and lastly, it ethylene glycol doesn't create pressure within the cooling system as it also has a a high boiling point. It is also comparatively easy to add anti-corrosives to the ethylene glycol-water mixture, to give added benefit to your car.
This film shows you how to check and change the antifreeze in your car: