The video explains the anomalous expansion of water, where water contracts until 4°C and then expands. This property is crucial for aquatic life in cold climates, as it allows ice to form on the surface of bodies of water, insulating the water below and maintaining a habitable environment for aquatic organisms.

What is the unique behavior of water when it is heated from 0°C to 4°C?

• It expands in volume.

• It contracts in volume.

• It remains the same in volume.

• It evaporates.

At what temperature does water have its maximum density?

• 0°C

• 2°C

• 4°C

• 6°C

What does the graph between temperature and volume of water illustrate?

• Water's chemical composition.

• Anomalous expansion of water.

• Water's freezing point.

• Water's boiling point.

How does the anomalous expansion of water benefit aquatic life in cold climates?

• It decreases the water density.

• It raises the water temperature.

• It prevents water from freezing completely.

• It increases the oxygen level in water.

What happens to the topmost layer of water when the temperature falls below 4°C?

• It becomes denser.

• It sinks to the bottom.

• It expands and floats.

• It evaporates.

Why does ice float on the surface of water?

• Ice has a higher temperature than water.

• Ice is heavier than water.

• Ice is less dense than water.

• Ice is denser than water.

What role does the ice layer play in maintaining the temperature of water bodies?

• It allows heat to escape.

• It decreases the water temperature.

• It prevents heat from escaping.

• It increases the water temperature.

How does the formation of ice affect the aquatic life in ponds and lakes?

• It provides a habitat for fish.

• It increases the water's salinity.

• It restricts the movement of fish.

• It helps maintain a livable temperature.

What is the term used to describe the unique behavior of water when it expands upon freezing?

• Physical expansion

• Thermal expansion

• Anomalous expansion

• Chemical expansion