Cut a piece of black KG carboard so that it fits at the base of the shallow bowl. In a vessel, add 1 table spoon of Epsom salt to ¼ or ½ cup of warm water. Stir until the salt gets dissolved. Pour this solution into the shallow bowl containing the black KG card board at its base. Leave the bowl in a place where there is direct sunlight and ask the students to observe what happens.
Instruction to the teachers
At the end of the activity, initiate a discussion by asking the following type of questions.
i) What happened to the mixture ?
ii) Name the process involved.
iii) How long did it take for the mixture to dry up ?
l Draw their attention to the fact that this is how salt is extracted from sea - water.
l To make this activity even more interesting, ask the students to observe the shape of the crystals under a microscope.
l Then, ask the students to try the same experiment using sugar and salt.
Note : This activity can be made colourful using different salts.