[paul.fr]

Ok, the other night i left a glass of water out(tap water). when i awoke the next day, it had bubbles in it!

So last night at work i got 3 glasses. the first i filled with water from the tap, the second i filled with hot water from a wall mounted water boiler and the third i filled with chilled water from a water cooler.

These were the results:

glass of tap water >100 bubbles
hot water 0 (zero) bubbles
chilled water <20 bubbles

why the difference?

addition: the glasses were left untouched for 8 hours, and the bubbles formed on the side of the glass.

[another_someone]

Water ordinarily has gasses from the air dissolved in it.

If you leave the water standing, these gasses will to some extent come out of solution, the bubble nucleating wither around flaws in the glass, or around dust suspended in the water, or around radiation trails from cosmic radiation.

Boiled water will tend to have much of the gas expelled from the water, so there will be very little gas left dissolved in the water to form bubbles.