Solid, liquid, and gas - the three states of water. We see water freeze and turn to ice and we see water evaporate and turn to gas but... have you ever seen ice evaporate directly to gas? This process is called sublimation and you can read all about it below.
Note: This section of the Water Science School discusses the Earth's "natural" water cycle without human interference.
• Water Science School HOME • The Water Cycle •
Water cycle components » Atmosphere · Condensation · Evaporation · Evapotranspiration · Freshwater lakes and rivers · Groundwater flow · Groundwater storage · Ice and snow · Infiltration · Oceans · Precipitation · Snowmelt · Springs · Streamflow · Sublimation · Surface runoff
Sublimation and the Water Cycle

Credit: Wikimedia Commons, Creative Commons License
Sublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water. The opposite of sublimation is "deposition", where water vapor changes directly into ice—such a snowflakes and frost.
It is not easy to actually see sublimation occurring, at least not with ice. One way to see the results of sublimation is to hang a wet shirt outside on a below-freezing day. Eventually the ice in the shirt will disappear. Actually, the best way to visualize sublimation is to not use water at all, but to use carbon dioxide instead. If you don't know what I mean, then look at this picture of dry ice. "Dry ice" is actually solid, frozen carbon dioxide, which happens to sublimate, or turn to gas, at a chilly -78.5 °C (-109.3°F). The fog you see is actually a mixture of cold carbon dioxide gas and cold, humid air, created as the dry ice "melts" ... oops, I mean sublimates. Find out more about dry ice.
From Mt. Everest to the Chinook winds
Sublimation occurs more readily when certain weather conditions are present, such as low relative humidity and dry winds. Sublimation also occurs more at higher altitudes, where the air pressure is less than at lower altitudes. Energy, such as strong sunlight, is also needed. If I was to pick one place on Earth where sublimation happens a lot, I might choose the south face of Mt. Everest. Low temperatures, strong winds, intense sunlight, very low air pressure — just the recipe for sublimation to occur.
Dave Thurlow of the Mount Washington Observatory offers a good explanation of sublimation in The Weather Notebook:
"There's more than one way for Mother Nature to get rid of a fresh blanket of snow. The most common way, of course, is by melting-which gives everyone the pleasure of trudging through slush, mud, and water. But in the western U.S., there's a wind called the Chinook, or "snow eater," that vaporizes snow before it even has a chance to melt."
"Chinook winds are westerlies from the Pacific whose moisture gets wrung out as it passes over the Rocky Mountains. Once these winds come down from the mountains onto the high plains, they can be quite mild and extremely dry-as warm as 60 or 70 degrees Fahrenheit — over 15 Celsius — with a relative humidity of 10% or less. The air is so dry that when it hits a snowpack, the frozen water evaporates, going directly from the ice to vapor and bypassing the liquid phase entirely. This is called sublimation, and it's a common way for snow to disappear in the arid West."
Can't sublimate without the heat
Without the addition of energy (heat) to the process, ice would not sublimate into vapor. That is where sunlight plays a large role in the natural world. Water has a physical property called the "heat of vaporization," which is the amount of heat required to vaporize water. If you want an exact amount of heat, the heat of vaporization of water is 540 calories/gram, or 2,260 kilojoules/kilogram. That is a lot more energy than is needed to convert water to ice (the latent heat of fusion), which is 80 calories/gram. And, it is also about five times the energy needed for heating water from the freezing point to the boiling point. In summary, energy is needed for the sublimation of ice to vapor to occur, and most of the energy is needed in the vaporization phase. A cubic centimeter (1 gram) of water in ice form requires 80 calories to melt, 100 calories to rise to boiling point, and another 540 calories to vaporize, a total of 720 calories. Sublimation requires the same energy input, but bypasses the liquid phase.
Sources and more information
- Sublimation, Wikipedia
- Dry ice, Wikipedia
More topics and other components of the water cycle:
The Fundamentals of the Water Cycle
The Water Cycle for Adults and Advanced Students
Precipitation and the Water Cycle
A Comprehensive Study of the Natural Water Cycle
Streamflow and the Water Cycle
Snowmelt Runoff and the Water Cycle
Evaporation and the Water Cycle
Surface Runoff and the Water Cycle
Infiltration and the Water Cycle
The Atmosphere and the Water Cycle
Springs and the Water Cycle
Condensation and the Water Cycle
Ice, Snow, and Glaciers and the Water Cycle
- Overview
Solid, liquid, and gas - the three states of water. We see water freeze and turn to ice and we see water evaporate and turn to gas but... have you ever seen ice evaporate directly to gas? This process is called sublimation and you can read all about it below.
Note: This section of the Water Science School discusses the Earth's "natural" water cycle without human interference.
• Water Science School HOME • The Water Cycle •
Water cycle components » Atmosphere · Condensation · Evaporation · Evapotranspiration · Freshwater lakes and rivers · Groundwater flow · Groundwater storage · Ice and snow · Infiltration · Oceans · Precipitation · Snowmelt · Springs · Streamflow · Sublimation · Surface runoff
Sublimation and the Water Cycle
Sources/Usage: Some content may have restrictions. Visit Media to see details.A container holding dry ice (frozen carbon dioxide) sublimating into the air.
Credit: Wikimedia Commons, Creative Commons LicenseSublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water. The opposite of sublimation is "deposition", where water vapor changes directly into ice—such a snowflakes and frost.
It is not easy to actually see sublimation occurring, at least not with ice. One way to see the results of sublimation is to hang a wet shirt outside on a below-freezing day. Eventually the ice in the shirt will disappear. Actually, the best way to visualize sublimation is to not use water at all, but to use carbon dioxide instead. If you don't know what I mean, then look at this picture of dry ice. "Dry ice" is actually solid, frozen carbon dioxide, which happens to sublimate, or turn to gas, at a chilly -78.5 °C (-109.3°F). The fog you see is actually a mixture of cold carbon dioxide gas and cold, humid air, created as the dry ice "melts" ... oops, I mean sublimates. Find out more about dry ice.
From Mt. Everest to the Chinook winds
Snowy mountains in western Canada. Sublimation occurs more readily when certain weather conditions are present, such as low relative humidity and dry winds. Sublimation also occurs more at higher altitudes, where the air pressure is less than at lower altitudes. Energy, such as strong sunlight, is also needed. If I was to pick one place on Earth where sublimation happens a lot, I might choose the south face of Mt. Everest. Low temperatures, strong winds, intense sunlight, very low air pressure — just the recipe for sublimation to occur.
Dave Thurlow of the Mount Washington Observatory offers a good explanation of sublimation in The Weather Notebook:
"There's more than one way for Mother Nature to get rid of a fresh blanket of snow. The most common way, of course, is by melting-which gives everyone the pleasure of trudging through slush, mud, and water. But in the western U.S., there's a wind called the Chinook, or "snow eater," that vaporizes snow before it even has a chance to melt."
"Chinook winds are westerlies from the Pacific whose moisture gets wrung out as it passes over the Rocky Mountains. Once these winds come down from the mountains onto the high plains, they can be quite mild and extremely dry-as warm as 60 or 70 degrees Fahrenheit — over 15 Celsius — with a relative humidity of 10% or less. The air is so dry that when it hits a snowpack, the frozen water evaporates, going directly from the ice to vapor and bypassing the liquid phase entirely. This is called sublimation, and it's a common way for snow to disappear in the arid West."
Can't sublimate without the heat
Without the addition of energy (heat) to the process, ice would not sublimate into vapor. That is where sunlight plays a large role in the natural world. Water has a physical property called the "heat of vaporization," which is the amount of heat required to vaporize water. If you want an exact amount of heat, the heat of vaporization of water is 540 calories/gram, or 2,260 kilojoules/kilogram. That is a lot more energy than is needed to convert water to ice (the latent heat of fusion), which is 80 calories/gram. And, it is also about five times the energy needed for heating water from the freezing point to the boiling point. In summary, energy is needed for the sublimation of ice to vapor to occur, and most of the energy is needed in the vaporization phase. A cubic centimeter (1 gram) of water in ice form requires 80 calories to melt, 100 calories to rise to boiling point, and another 540 calories to vaporize, a total of 720 calories. Sublimation requires the same energy input, but bypasses the liquid phase.
Sources and more information
- Sublimation, Wikipedia
- Dry ice, Wikipedia
- Science
More topics and other components of the water cycle:
The Fundamentals of the Water Cycle
Earth's water is always in movement, and the natural water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Water is always changing states between liquid, vapor, and ice, with these processes happening in the blink of an eye and over millions of years.Filter Total Items: 16The Water Cycle for Adults and Advanced Students
Earth's water is always in movement, and the natural water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Water is always changing states between liquid, vapor, and ice, with these processes happening in the blink of an eye and over millions of years. Note: This section of the Water Science School discusses the...Precipitation and the Water Cycle
The air is full of water, even if you can't see it. Higher in the sky where it is colder than at the land surface, invisible water vapor condenses into tiny liquid water droplets—clouds. When the cloud droplets combine to form heavier cloud drops which can no longer "float" in the surrounding air, it can start to rain, snow, and hail... all forms of precipitation, the superhighway moving water...A Comprehensive Study of the Natural Water Cycle
Earth's water is always in movement, and the natural water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Water is always changing states between liquid, vapor, and ice, with these processes happening in the blink of an eye and over millions of years. Note: This section of the Water Science School discusses the...Streamflow and the Water Cycle
What is streamflow? How do streams get their water? To learn about streamflow and its role in the water cycle, continue reading. Note: This section of the Water Science School discusses the Earth's "natural" water cycle without human interference.Snowmelt Runoff and the Water Cycle
Perhaps you've never seen snow. Or, perhaps you built a snowman this very afternoon and perhaps you saw your snowman begin to melt. Regardless of your experience with snow and associated snowmelt, runoff from snowmelt is a major component of the global movement of water, possibly even if you live where it never snows. Note: This section of the Water Science School discusses the Earth's "natural"...Evaporation and the Water Cycle
For the water cycle to work, water has to get from the Earth's surface back up into the skies so it can rain back down and ruin your parade or water your crops or yard. It is the invisible process of evaporation that changes liquid and frozen water into water-vapor gas, which then floats up into the skies to become clouds. Note: This section of the Water Science School discusses the Earth's...Surface Runoff and the Water Cycle
Runoff is nothing more than water "running off" the land surface. Just as the water you wash your car with runs off down the driveway as you work, the rain that Mother Nature covers the landscape with runs off downhill, too (due to gravity). Runoff is an important component of the natural water cycle. Note: This section of the Water Science School discusses the Earth's "natural" water cycle...Infiltration and the Water Cycle
You can't see it, but a large portion of the world's freshwater lies underground. It may all start as precipitation, but through infiltration and seepage, water soaks into the ground in vast amounts. Water in the ground keeps all plant life alive and serves peoples' needs, too. Note: This section of the Water Science School discusses the Earth's "natural" water cycle without human interference.The Atmosphere and the Water Cycle
The atmosphere is the superhighway in the sky that moves water everywhere over the Earth. Water at the Earth's surface evaporates into water vapor which rises up into the sky to become part of a cloud which will float off with the winds, eventually releasing water back to Earth as precipitation. Note: This section of the Water Science School discusses the Earth's "natural" water cycle without...Springs and the Water Cycle
A spring is a place where water moving underground finds an opening to the land surface and emerges, sometimes as just a trickle, maybe only after a rain, and sometimes in a continuous flow. Spring water can also emerge from heated rock underground, giving rise to hot springs, which people have found to make a delightful way of soaking away their problems. Note: This section of the Water Science...Condensation and the Water Cycle
The air is full of water, as water vapor, even if you can't see it. Condensation is the process of water vapor turning back into liquid water, with the best example being those big, fluffy clouds floating over your head. And when the water droplets in clouds combine, they become heavy enough to form raindrops to rain down onto your head. Note: This section of the Water Science School discusses the...Ice, Snow, and Glaciers and the Water Cycle
Ice and glaciers are part of the water cycle, even though the water in them moves very slowly. Ice caps influence the weather, too. The color white reflects sunlight (heat) more than darker colors, and as ice is so white, sunlight is reflected back out to the sky, which helps to create weather patterns. Read on to learn how glaciers and ice caps are part of the water cycle. Note: This section of... - Multimedia