The method described here is used in laboratories to prepare pure distilled water. But the basic method remains the same if you want to prepare it at home. You will need utensils of appropriate size and design for this purpose. Look at the diagram given below to have an idea.
Two jars or beakers with lids, Glass tube (having openings at both ends), Capillary tube, Utensil (large enough to hold jar and ice), Burner.
Fill one jar with ordinary tap water. Cover it with the lid. This lid must have an opening to insert the glass tube in it. Place second jar inside the utensil. This second jar should be covered with the lid having two holes in it. Now, insert a glass tube through lids of both jars to connect them with each other. Insert a small capillary tube into empty hole of lid of second jar to make it act like a chimney for steam. Second jar must be covered with ice from outside. Ice will act as a condenser for incoming steam. The tube connecting both jars must be going deep inside the second jar.
Now, boil the water of first jar. The steam will rise and enter into the second jar through the glass tube. It will get condensed into pure distilled water. Extra steam will escape through the capillary tube. The process of distillation is very slow and takes time. Therefore, one should be patient during the process.
– Steam can cause serious burns. Be careful.
– Use jars or beakers made from glass which can tolerate high temperature of flame and steam.
Please note, the image shown above is for reference purpose only, to give a general idea about how water is distilled. Actual setup will be different. Distilled water has certain medical and industrial uses. Flooded lead acid batteries should be topped up with distilled or deionised water.