Density

Anomalies surrounding the famous density anomaly of water -- why ice floats and why water reaches its maximum density at 4 degrees Celsius.

Advanced Locked #15

The density of ice increases upon warming up to 70 K

At low temperatures, ice expands upon cooling instead of contracting.

Accessible Locked #16

Water shrinks on melting

Unlike most substances, liquid water is denser than solid ice.

Accessible Locked #18

Cold liquid water has a high density that increases upon warming

Water reaches its maximum density at 3.984 degrees Celsius, not at the freezing point.

Advanced Locked #19

The surface of water is denser than the bulk

The surface layer of water has a higher density than the interior.

Advanced Locked #21

The density of supercooled water has a minimum

Supercooled water shows a density minimum before crystallizing.

Advanced Locked #22

Water has a low expansion coefficient

The thermal expansion coefficient of water is unusually low.

Advanced Locked #23

Thermal expansion of water decreases increasingly at low temperatures

Upon cooling below 4 degrees Celsius, thermal expansion becomes negative -- water expands upon cooling.

Advanced Locked #25

The number of nearest neighbors increases on melting

Upon melting, the coordination number increases even though volume decreases.

Advanced Locked #26

The number of nearest neighbors increases with temperature

With increasing temperature, the number of nearest neighbors in liquid water increases.