You will need
1 smaller glass jar
Large transparent polythene sheet
Large rubber bands
Stone
Salt
Wide plastic bowl
Water
We have all heard the phrase, “Water, water everywhere not a drop to drink.” But what if you can change the dirty water or salty water into clean water?
INSTRUCTIONS
- Since we do not want to fall sick, for the experiment take clean water and mix 1-2 tablespoonfuls of salt into the water.
- Pour this water into a wide plastic bowl.
- Next, place a smaller glass jar in the centre
of the plastic bowl filled with salty water.
But make sure that the water level is below
the height of the glass. - Cover the bowl with a large transparent polythene sheet and secure it around the edges with rubber bands. Make sure it is absolutely sealed.
- Take a small stone and place it in the centre of the plastic bowl over the area of the glass jar.
- Place this ‘solar still’ in the sun. Leave it like that for 3-4 hours in direct sunlight.
- While you wait, make observations about what is going on inside the ‘solar still’
RESULT
After 3-4 hours, there would be water collected inside the smaller jar placed in the centre, which will be clean and not at all salty. The water evaporates due to sunlight and leaves behind impurities including salt. However, in our make-shift ‘solar still’, the water which evaporates reaches the transparent polythene sheet, and travels towards the centre of the sheet dripping back into the jar, because of the stone weighing the polythene sheet down.
