Question: How can I get 100% pure water that can form supercool liquid water?

Paula Salgado answered on 13 Jun 2010:

Hi

To get 100% pure water is possible but highly inefficient. As soon as you contain the water you are producing, you contaminate it with small particles (impurities) at the surface of your container.

What you might want to know is how to get distilled or purified water – like the one we use in our labs. We basically use very speciallised filters that retain most small particles. Heat is also used to sterilise water, that is to eliminate any possible microbiological contaminants. Finally, the most common process to purify water is to distill it.

Distilling water means you heat it until it starts boiling (it vapourises) and then collect the steam in a cold surface – the water becomes liquid again on contact with the cold surface and the droplets are collected. Since the impurities are not volatile at the same temperature as water, they are not present in the vapour, so will not be there in the collected liquid – single distilled water. This is not a process 100% efficient and is often repeated so you have double or triple distilled water.

There is a simple way to distill water at home. Get two bottles,at least one transparent that you fill with water. Then join the two bottles together by the neck. You then have to find a place to put them so that the bottle with water is in the sun (so it heats up) and the other kept cool in the shade or covered and angled so that water will collect in the bottom. The heat causes evaporation of water in the filled bottle which then condenses in the cooler bottle and collects as distilled water at the bottom.

You can then do your supercooling experiment by placing your bottle of collected distilled water in the freezer. Allow the bottle of water to chill, undisturbed, for about 2-1/2 hours. The exact time it will take for water to supercool depends on your freezer, so place a bottle of mineral or tap water at the same time. When the tap water freezes, the pure water is supercooled. If the purified water also freezes, you either waited too long, somehow disturbed the container, or else the water was insufficiently pure.

Hope that works! And do let me know the results you got if you try it! 😉