Why is water clear in a glass but appears blue in a white bath?
The reason in a glass it appears clear and in a larger scale such as the sea (or perhaps the bath, though Ive never seen it blue in the bath…perhaps your bath water is full of dissolved impurities like Cu2+, lol) is because water defragments light. What happens is as light travels through water, the water “bends” the light. In actuality, it slow it down so that the angle of the light hitting the water is altered by the time it departs from it. Colour is where light has different wavelengths, such as the colour red has a wavelength of 700nm (nanometre) and violet has a wavelength of 400nm. When light hits objects, they absorb all wavelengths of light except that of the colour we see. Therefore if we look at a brown table, the table reflects only brown light and absorbs all other colours (wavelengths) of light. In a similar way, water absorbs all frequencies of light except a certain frequency of blue. The frequency of blue is 450–495 nm, through ranging between 450–495 nm, we get diff
