A higher concentration leading to dark pink water can be used as an antiseptic . A very concentrated dark purple solution can be used as an anti-fungal agent to treat things like athletes foot. Rocks Not the most exciting part of GCSE chemistry, but rocks have their uses. In times of water shortage soldiers put a pebble into their mouth to help reduce water loss from their mouth from respiration. Oh, yes i nearly forgot.
Pebbles are smooth because they are constantly being moved by tides and waves.
They bash into each other and eventually become rounded and smooth. Chip off the old block so to speak. No this is not a cunning way to get in a rude expression. In fact you can get the water back from urine to produce drinking water if it is distilled . Bet they don't let you try this one at school.