Top up of water - CAR - cooling system - anti freeze?

I have a low coolant level in my 2004 ford card.
i was told i need a top up of antifreeze or just a pure water should do good for the time being. As they say, antifreez is nothing but a mix of water.
what is the difference between topping up with pure water and a actual antifree here.

You are changing the dilution of the solution. The properties of the solution weaken.

Antifreeze/Coolant has corrosion protection and lubricants for things like the water pump. It also significantly lowers the freezing point of the water so your block doesn't crack in cold weather. The water is what actually cools the engine, but it also rusts out parts and does a poor job lubricating anything. Because of this, you mix antifreeze with the water.

You CAN just add plain water for a temporary fix. However, if you ran just water in your coolant system, it would rust and clog relatively quickly. It would also damage the engine if the tempeature fell below 32 degrees (0 C).

Coolant should be a 50/50 mix of water and antifreeze. If you add just water or just antifreeze you will change the mix. Too much water and the engine will corrode.
As an absolute emergency get you home measure you can add just water but you need to get the solution back to a 50/50 mix as soon as possible.

1) Pure water corrode engine guts, antifreeze won't.
2) Water freeze at and boil at while antifreeze won't start freezing up to and boil at
3) A water leak on a hot engine won't leave any visible trait. An antifreeze leak would leave a color stain.
4) Unless you use distilled water, dissolved minerals would build up and block everything.
5) Doesn't have to be an expensive antifreeze. I have +5 years using a really cheap one (US$3/gl) in a 1987 Honda Accord and haven't have any problem (by contrast, a work colleague use water and is always complaining about water pump, hoses, radiators and a myriad of problems in a Corolla 2010)

Ponderer keeps it short and sweet FTW.