What is ice turning into water called?

By YourDictionary Staff

Table of Contents Show

Water is a molecule
Changing states of matter and energy
Water can change state over and over again

When ice turns directly into water vapor without first transitioning into a liquid, it is referred to as "sublimation." In fact, any solid that turns into a vapor without going through the liquid phase can be said to sublime or "sublimate."

There are many examples of ice to water vapor. Here are some examples as well as some examples of similar phase changes:

Below the melting point temperature, at which point water will turn into water, ice can sublime - that is, transition from a frozen state directly into a vapor state. Sublimation of ice can be demonstrated in hanging a wet sweater on a line in freezing temperatures. Although it may take a few days, the wet clothing article will eventually dry out.
Snow, which is a particular type of ice crystal, can also transition directly into water vapor. On cold, gray days even when it's too cold for snow to melt, it will eventually sublime into the air as water vapor.
Freeze-drying uses the process of sublimation to preserve certain materials, particularly food items. "Astronaut ice cream," for example, uses sublimation. The material to be freeze-dried is frozen and then placed into a vacuum or under low pressure and the moisture is allowed to sublime.
Glaciers are giant chunks of ice that covered the entire globe during the Ice Age, and still exist. Glaciers experience a particular form of sublimation called ablation. Ablation is the process wherein the snow and ice of the glacier slowly begins to turn into vapor.

A few materials other than ice experience sublimation as well. Here are some examples of other types of sublimation.

Carbon dioxide gas can be frozen into a block commonly known as "dry ice." Although it's not the same as the ice in your drink, dry ice experiences sublimation in a very similar way (although it's not nearly as slow). It sublimes directly into carbon dioxide gas without changing into a liquid form.
Iodine, an element used in nutrition and manufacturing, can also sublime under certain, special circumstances. Sublimated iodine fumes can reveal fingerprints in forensic research.
At very high temperatures, the dangerous element arsenic can sublime. How high must the temperature be? Sublimation of arsenic only occurs at temperatures above 1100 degrees Fahrenheit.
Naphthalene is an organic compound that is primarily known to the average person as the main ingredient in mothballs. This compound sublimes very well - as a matter of fact, engineering students often study naphthalene vapor as a means to better understand large scale sublimation.
Ferrocene, an orange colored organometallic compound, is able to sublime - particularly when placed into a vacuum and heated to a high temperature.
The hydrocarbon anthracene, a coal tar component that can be used to make red dye, is a compound that can sublime.
Pyrene is apolycylic aromatic hydrocarbon that can sublime at certain pressure conditions and temperatures.

Now you have lots of examples of ice to water vapor, as well as some examples that illustrate how the process of ice to water vapor works.

Water can exist as a solid (ice), liquid (water) or gas (vapour or gas). Adding heat can cause ice (a solid) to melt to form water (a liquid). Removing heat causes water (a liquid) to freeze to form ice (a solid). When water changes to a solid or a gas, we say it changes to a different state of matter. Even though the water’s physical form changes, its molecules stay the same.

Water is a molecule

A molecule is a group of two or more atoms that bond or ‘stick’ together. Water is a molecule. It is made up of two hydrogen (H) atoms and one oxygen (O) atom that are chemically bonded together. The H and O are symbols for the atoms that make up water. This is why people often refer to water as H2O. Water can change from a liquid to a solid or a gas and back to a liquid, but its molecules always stay the same. A water molecule is always H2O whether it is liquid water, ice or water vapour.

Numerous everyday words, like energy, have a different meaning in science. We talk about running out of energy during a race or children having too much energy. Scientists define energy as the potential to do work – such as heating or cooling water to make it change state.

Changing states of matter and energy

Water, like all other types of matter, requires the addition or removal of energy to change states. A block of ice is solid water. When heat (a form of energy) is added, the ice melts into liquid water. It has reached its melting point – 0°C. Continue to apply heat, and the water will turn into water vapour, which is water in its gaseous state. The water has reached its boiling point – 100°C.

If heat is removed from water vapour, the gas cools down and it condenses back into liquid water. Continue to cool the water (by removing heat), and it becomes solid ice. This is its freezing point.

Water can change state over and over again

You may have heard that the water you drink today is the same water that dinosaurs drank thousands of years ago. Nature recycles water. It can be melted, frozen and evaporated again and again. There is no loss of water during or after it changes form. Frozen water (ice) takes up more space than liquid water because it is less dense, but when the ice melts, it is the same amount of water as before although some of it may be in the form of water vapour.