Vipul Jain

​​​​Why does water gets cooled in Earthen Pot? Water inside earthen pot rises to surface of pot by capillary action through tiny pores on the pot. Now this water at surface comes in contact with the hot surrounding air and evaporates (as Dry Bulb Temperature of Air is high, in simple terms air is hot and dry). Now whenever a Substance evaporates, it needs energy (Latent Heat of Vaporization), Here this energy comes in the form of heat (Sensible heat) from remaining water inside pot. In a simplified way, The Surrounding air is Hot and dry hence it absorbs water at the surface of earthen pot in the form of vapor. For conversion of water in vapor energy is required, which is absorbed from water inside the pot, resulting in decreasing its temperature. Or in short, when anything evaporates on the surface, the surface gets colder. This answers another question, Why does our hands feel colder after applying hand Sanitizers.

Why Water has no colour? Lab measurements show that water does have a colour, pale blue. Given the blue colour of the sea, that may come as little surprise. But according to Dr Martin Chaplin, an expert on the properties of water, its colour has a specific cause. Its origins lie in the way the water molecule interacts with incoming light. The molecule’s two hydrogen atoms sit at the ends of two spring-like ‘legs’ joined midway by the oxygen atom. The resulting V-shaped combination can vibrate in various ways, mopping up different wavelengths of light. But it’s particularly effective at absorbing longer, redder wavelengths, while leaving shorter, bluer wavelengths fairly untouched. The result is a pale blue colour. Water scatters shorter wavelengths more effectively, leading to more of the blue component of sunlight reaching our eyes.

Why Is Water Wet? 'Wet' is ultimately just a word that applies to water. What we feel as wetness is actually coldness as the water evaporates. Below is an experiment from the Institute of Physics to test the feeling of 'wetness' between two different liquids: The feeling of wetness is actually coldness. You can test this by comparing water with another liquid - cooking oil - which doesn't evaporate so freely Liquids make surfaces wet (i.e. they stick to many solid surfaces) due to the electrostatic (opposite charges) forces between molecules. Water is polar—it has an uneven spread of electrical charge—which makes one end of the molecule positive and the other end negative. This causes water to be attracted to many surfaces and also explains many other properties of water.