The photo shows some secondary grade teachers (teaching science for 6th,7th and 8th classes) trying out Earthlearningidea 'Salt of the Earth' during the In-Service training programme for secondary grade science teachers of Theni district. This was organised by Jayaraj Annapackiam College for Women, Periyakulam, India, sponsored by Tamil Nadu State Council for Science and Technology, Chennai, India during January 2009. The demonstrator is Jothi. The teachers will ask their students to carry out this experiment in their homes with available vessels and wait for three months. They will then be asked to display their sodium chloride crystals. The student who has grown the largest crystal will be rewarded with a good book and will be asked to explain to the others the procedure he/she has followed in growing the biggest crystal.
Have you tried this Earthlearningidea? Who can make the biggest crystal with the most perfect shape? The activity provides a practical example of chemistry in action. Salt, sodium chloride, is a vital commodity; ask your pupils to investigate the main sources of supply of salt for their country.