The solid form of water is called ice.

Explanation:
Water exists in three different forms: solid, liquid, and gas. The solid form of water is known as ice. When water reaches a temperature of 0 degrees Celsius or below, it freezes and turns into ice.

Here are some key points to understand about ice:

Definition:
Ice is the solid state of water, which occurs when water molecules slow down and come together to form a crystalline structure.

Formation:
Ice forms when the temperature of water drops below its freezing point, which is 0 degrees Celsius (32 degrees Fahrenheit). As the temperature decreases, the water molecules start moving slower and closer together, forming a regular pattern or lattice structure.

Properties:
- Solid and rigid: Ice is a solid substance with a fixed shape and volume. It maintains a rigid structure due to the arrangement of water molecules in a lattice.
- Less dense than liquid water: When water freezes, it expands and becomes less dense. This is why ice floats on water bodies like lakes, rivers, and oceans.
- Translucent: Ice is usually transparent or translucent, allowing light to pass through it to some extent.
- Brittle: Ice is relatively brittle and can easily break or crack under pressure.

Uses:
Ice has various uses in our daily lives, including:
- Cooling and preserving food: Ice is commonly used in refrigeration and freezing to keep food fresh.
- Beverages: Ice cubes are used to chill drinks, making them refreshing on hot days.
- Sports and recreation: Ice is used for ice skating, ice hockey, and other winter sports.
- Scientific research: Ice cores drilled from glaciers and ice sheets provide valuable information about past climates.

Conclusion:
The solid form of water is called ice. It forms when water freezes at or below 0 degrees Celsius and exhibits properties such as rigidity, reduced density, translucency, and brittleness. Ice has various practical applications in everyday life and scientific research.