Factors Influencing The Rate of Evaporation
- Concentration of the substance evaporating in the air
- If the air already has a high concentration of the substance evaporating, then the given substance will evaporate more slowly.
- Concentration of other substances in the air
- If the air is already saturated with other substances, it can have a lower capacity for the substance evaporating.
- Flow rate of air
- This is in part related to the concentration points above. If fresh air is moving over the substance all the time, then the concentration of the substance in the air is less likely to go up with time, thus encouraging faster evaporation. This is the result of the boundary layer at the evaporation surface decreasing with flow velocity, decreasing the diffusion distance in the stagnant layer.
- Inter-molecular forces
- The stronger the forces keeping the molecules together in the liquid state, the more energy one must get to escape. This is characterized by the enthalpy of vaporization.
- Pressure
- Evaporation happens faster if there is less exertion on the surface keeping the molecules from launching themselves.
- Surface area
- A substance that has a larger surface area will evaporate faster, as there are more surface molecules that are able to escape.
- Temperature of the substance
- If the substance is hotter, then its molecules have a higher average kinetic energy, and evaporation will be faster.
- Density
- The higher the density the slower a liquid evaporates.
In the US, the National Weather Service measures the actual rate of evaporation from a standardized "pan" open water surface outdoors, at various locations nationwide. Others do likewise around the world. The US data is collected and compiled into an annual evaporation map. The measurements range from under 30 to over 120 inches (3,000 mm) per year.
Read more about this topic: Evaporation
Famous quotes containing the words factors, influencing and/or rate:
“I always knew I wanted to be somebody. I think that’s where it begins. People decide, “I want to be somebody. I want to make a contribution. I want to leave my mark here.” Then different factors contribute to how you will do that.”
—Faith Ringgold (b. 1934)
“Do you believe that the dead can influence the living?... Could you conceive of a superhuman mentality influencing someone from the other side of death?... There is such a one.... Someone, something that reaches out from beyond the grave and fills me with horrible impulses.”
—Garrett Fort (1900–1945)
“Writing a book I have found to be like building a house. A man forms a plan, and collects materials. He thinks he has enough to raise a large and stately edifice; but after he has arranged, compacted and polished, his work turns out to be a very small performance. The authour however like the builder, knows how much labour his work has cost him; and therefore estimates it at a higher rate than other people think it deserves,”
—James Boswell (1740–1795)