"To wash clothing water must be forced through the tiny spaces between the fibres. This requires increasing the surface area of water". I didn't quite understand why surface area has to increase???
1 Answer
It is a curious way of phrasing it, but correct.
Explanation:
Imagine the water being in a single mass at the bottom of the tub. The water we’ll say takes up a cyclindrical shape and it’s surface area and volume can be calculated quite easily using the normal formulae: (
When the water is split into many smaller droplets (by being forced between the fibres) the value of r decreases immensely. This increases the area much faster than the volume. For simplicity assume they are still little cyclinders and you can prove this to yourself mathematically.
To keep it even simpler, assume the water exists as cubes and take two scenarios: a length of 20cm for each side (water in a mass at the bottom) and a length of 2mm for each side (water moving between fibres). Note the total volume of water will not alter in any case, assuming your machine does not leak and that absorption by the fibres has already happened.
