Why does water defy appear to defy gravity when evaporating?

  • Thread starter Thread starter azzkika
  • Start date Start date
  • Tags Tags
    Gravity Water
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
3 replies · 8K views
azzkika
Messages
60
Reaction score
0
why does water defy appear to defy gravity when evaporating??

Homework Statement


I am not the most astute at physics so please forgive my shortcomings, but i was wondering how it is that a saucepan of water cannot levitate, yet if left alone over time the water will levitate for a period before gravity pulls it down again.

As water is much heavier than air, i am puzzled as to the mechanics of evaporation and how at first glance, evaporation appears to defy Newtonian laws.




Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org


So does getting out of bed in the morning.
All gravity says is that there is a force downwards, it doesn't say that you can't produce a bigger force to overcome it.
When you boil water you add kinetic energy and the water molecules move around more - eventually they have enough energy to break away form their neighbours and escape as a gas.
 


mgb_phys said:
So does getting out of bed in the morning.
All gravity says is that there is a force downwards, it doesn't say that you can't produce a bigger force to overcome it.
When you boil water you add kinetic energy and the water molecules move around more - eventually they have enough energy to break away form their neighbours and escape as a gas.


Yes, but evaporation occurs way below boiling point, which should keep the water as a liquid. A glass of water will evaporate at room temperature, so why does the water not remain in the glass as a liquid??
 


azzkika said:
Yes, but evaporation occurs way below boiling point, which should keep the water as a liquid. A glass of water will evaporate at room temperature, so why does the water not remain in the glass as a liquid??

The measure of temperature is a measure of the average kinetic energy of the molecules involved. Individual molecules can have kinetic energies greater or less than this. Even at room temp, some molecules will have enough kinetic energy to escape as a gas and cause evaporation.