Hot answers tagged

5

As @Tweej suggests, it's because of water solubility. Because water molecules are quite polar, most things that are charged or polar are soluble in it (i.e.~"hydrophilic"). When a coffee stain dries up, the residue sticks to the surface. But when water is applied, it will readily mix with the water, and more easily be removed. Fats and oils are ...


2

If you put earthen pot in water before water inside pot reaches surface, then Yes, cooling will become faster. For instance, your hot utensil cools when plunged in water. But, final temperature of water inside pot is independent of above two ways of cooling.


2

You are just seeing differently illuminated clouds, as should be clear from this picture of an aircraft flying over a thunderstorm: Clouds are made of water droplets or ice crystal, which are transparent. When light is incident upon a cloud, it is scattered at the same wavelength (a process known as Mie scattering). This means that it remains of the same ...


2

For the hypothetical case of a thermally perfectly insulated system, I'm sure you can work out yourself from the specific heat and the enthalpy of fusion for water. Given that the enthalpy of fusion (330 kJ/kg) and the specific heat of ice (2 kJ/kg-K) have a ratio of 165 K, and you need the entire ice bucket to stay below the melting point, and your 20:1 ...


1

If the mouth of the bottle is small (e.g., a wine cork with drilled hole for a drinking straw), water indeed won't flow out. Would you also wonder why the water doesn't stay in an upside-down bucket (the limit case for a bottle with a very wide mouth)? What happens is that air enters through the mouth with a volume equal to the volume of water that leaves ...


1

Let's say that you have a vessel containing water and air and you start heating it. The temperature of the water and air inside will start to rise and so will the pressure, because the air would like to expand (but volume is fixed and water is almost incompressible). Since the boiling point of a substance depends on both pressure and temperature (for example ...


1

Based on the page linked in the comments, the answer seems to be the following: (1) The height of the puddle does not depend on the material of the surface so long as the surface is nonwetting. (2) If the amount of water is large then it makes no difference, but if the amount is small, such as a droplet, then the contact angle will become significant and ...


1

I guess your question is how to increase evaporation amount because the time is the droplet traveling time. To increase evaporation amount without changing air condition, followings can be considered. reduce droplet size: the evaporation rate is proportion to $\frac {1}{D^2}$, where D is droplet diameter. increase droplet speed: this can increase ...



Only top voted, non community-wiki answers of a minimum length are eligible