Recently our lovely soft water, which came from a loch high in the Cairngorm mountains, has been replaced by slightly hard water which comes from an underground borehole. Our kettle and our hot water tanks now pop and crackle loudly when the water is heating, rather than offering just a gentle hiss as before. Can anybody explain the reason for this odd effect when we are heating water with a higher mineral content?
• When an electric kettle is switched on, the element heats the water near it by convection. After that, small bubbles of vapour form on the element at nucleation points – areas that are slightly rougher than the rest of the element and which facilitate the change of state from liquid to gas.
As the small bubbles rise through the colder water, they collapse – or condense implosively – before they reach the surface, and release latent ...
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