91色情片

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?

鈥淢ust I absorb sunshine 鈥榙irectly鈥� to make vitamin D, or can it shine on me through glass windows?鈥�

V. M. Koritsas Otley, West Yorkshire, UK

We pay 拢25 for every answer published in New Scientist. To answer this question 鈥� or ask a new one 鈥� visit newscientist.com/lastword. Terms and conditions apply.

This article appeared in print under the headline 鈥淔ur-up ball鈥�