Ice

Solid state of water

For other uses, see Ice (disambiguation).

Ice is the solid state of water, occurring when water freezes at or below 0°C (32°F) under standard atmospheric conditions. Ice is a crucial component of the Earth's climate system and plays a significant role in various natural processes and human activities.

Formation

Ice block in Canal Park, Duluth

Ice forms when water molecules slow down due to a decrease in temperature, allowing hydrogen bonds to stabilize and create a crystalline structure. The most common form of ice on Earth is known as ice Ih, which has a hexagonal crystal lattice.

Structure

Ice Ih crystal lattice

The structure of ice is characterized by a regular arrangement of water molecules, each bonded to four others in a tetrahedral configuration. This arrangement results in a lower density than liquid water, which is why ice floats.

Types of Ice

Ice can exist in multiple forms, known as polymorphs, depending on the conditions of pressure and temperature. The most common types include:

• Ice Ih: The most prevalent form, found in glaciers and icebergs.
• Ice Ic: A cubic crystalline form that occurs at low temperatures.
• Ice II: A denser form that occurs under high pressure.

3D representation of several phases of water

Phase Diagram

Phase diagram of water

The phase diagram of water illustrates the conditions under which ice, liquid water, and water vapor coexist. It shows the triple point and critical point, highlighting the unique properties of water.

Natural Occurrences

Ice is found in various natural settings, including:

• Glaciers: Large masses of ice that move slowly over land.
• Icebergs: Floating chunks of ice that break off from glaciers.
• Sea ice: Frozen ocean water that forms and melts with the seasons.

Frozen Wappinger Creek

Human Uses

Ice has numerous applications in human activities, such as:

• Refrigeration: Used to preserve food and medicines.
• Sports: Essential for activities like ice skating and ice hockey.

Figure skating on ice

Phenomena

Ice can form unique natural phenomena, such as:

• Ice circles: Rare circular formations that occur in slow-moving water.
• Grease ice: A thin, soupy layer of ice crystals forming on the sea surface.

Ice circle on Tsu Lake

Grease ice formation

Related Pages

• Water
• Snow
• Glacier
• Iceberg
• Sea ice