I live in a hard water area and use a stainless steel mesh ball in my kettle to stop it 鈥渇urring up鈥�. The steel mesh traps the scale that would otherwise form inside my kettle. How does it work?
鈥� If you want to get rid of something, you can use a chemical, physical or biological agent 鈥� or you can provide a different environment that it prefers.
Some gardeners use sacrificial planting of nasturtiums to attract aphids and thus protect their prized plants, rather than using pesticides. Aphids can then be physically removed from the nasturtiums, or the most infected plant parts can be destroyed, leaving the rest to carry on the good work.
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In a similar manner, limescale is deposited preferentially on the stainless steel mesh ball because the mesh has far more nucleation sites than the kettle. These sites are discrete points, such as microscopic scratches, where the crystallisation of limescale (mostly calcium carbonate) starts. The mesh ball won鈥檛 capture all the deposited limescale, but it can be periodically soaked in vinegar to dissolve the build-up and then reused.
鈥淟imescale is deposited on the steel mesh because it has more nucleation sites than the kettle鈥�
Don鈥檛 be tempted to use cheap wire wool bought in hardware stores. This will corrode and the rust will make your tea and coffee browner than usual.
David Muir, Science Department, Portobello High School, Edinburgh, UK
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This article appeared in print under the headline 鈥淔ur-up ball鈥�