Ever noticed that a glass of water tastes a little, ermm, different after it's been left out overnight? Fortunately there's a scientific explanation for this flavour phenomenon, so you can rest easy with out suspecting spiders, gremlins  or other such terrors of the night tampering with your bedside quality water glass.

• Overnight water absorbs CO2, altering taste.
• Bottled water's "expiration" due to plastic leeching.
• Water essential for health and well-being.

Discovery News have come forward with an explanation. Apparently, as water interacts with the air around it, it absorbs little amounts of carbon dioxide and forms teeny-tiny portions of carbonic acid. Lowering the liquid's