功課一問...２０分

Distillation:

In distillion, water is boiled to become steam. The steam then condenses upon cooling. Distillation can remove the solid inpurities, soluble minerals and micro-organisms in water. Therefore, distillation is safe to drink.

Filtration:

The method of purifying water by passing it through a filter to remove solid impurities is called filtration. The liquid which passes through the filter is called filtrate. The solid material remaining on the filter is called residue.

2007-03-11 23:21:58 補充：
Sedimentation...Sedimentation is the simplest method for putifying water. It can remove large insoluble impurities in water. During sedimentation, layer of sediment. The water thus becomes clearer. Sedimentation is the first step of water purification in a water treatment plant.

2007-03-11 23:22:09 補充：
There are three methods to check the distilled water...1. Distillation 2. Filtration 3.Sedimentation

我諗到幾個方法，不過分別可能很少。
導電率﹝蒸餾水應該絶緣﹞
比重﹝蒸餾水是1.0﹞
酸鹼值﹝中性7.0﹞
同你一定要的蒸餾法，不過都唔肯定怎樣做，用沸點？用殘留物？