text: why anything becomes dark in colour when it absorb water and the things which don't seems to be remainunchange i can explain it as ,the sand on the bank of riverloooks green but if some water is pored on it ,it looks blakish or the same thing happens with our wet clothes as become dark in comparision with usual colour..the same things not happen wiht the materials that don't absorb water. things that look darker when soaked absorb water. the surface tension of water brings the small particles (fibre of a cloth or sand-dust) close 2 each other. as a result the density of the wet thing increases. this causes the object 2 reflect light of a different (greater?) wavelength & the colour darkens.