758. Why does water dissolve various substances?
Because the atoms of water are very minute; they therefore permeate the pores, or spaces, between the atoms of those bodies, and overcoming their attraction for each other, cause them to separate.
759. Why does hot water dissolve substances more readily than cold?
Because the heat assists to repel the particles of the substance undergoing solution, and gives the water a freer passage between the atoms.
760. Why is pump water sometimes hard?
Because, in passing through the earth, it has become impregnated with mineral matters, usually the sulphate and carbonate of lime.
Because it is derived from vapours which, in ascending to the clouds, could not bear up the mineral waters with them. It therefore became purified or distilled.
762. Why do kettles become encrusted with stony deposits?
Because that portion of the water which is driven off in steam leaves the mineral matters behind; they therefore form a crust around the sides of the kettle.