The science of ice.

Why is ice slippery?

Water is formed by two positive hydrogen molecules bonding together with one negative oxygen molecule. The opposite charges attract other water molecules forming hydrogen bonds. The water molecules move about closely and the hydrogen bonds are easily broken and made. As the thermal energy is lost water molecules slow down. They form into rigid hexagonal groups that connect together to form cyrstal lattices. As ice thickens they form in all directions making ice hard. Surface molecules can't form bonds and are in a loose liquid state called pre-melt. Pre-melt allows frictionless movement and this is why ice is slippery.
Vanilla Ice - Ice Ice Baby (Official Music Video)

Thermodynamics of ice

Processes that affect the growth and melt of sea ice are referred to as thermodynamics. In the simplest sense, when the temperature of the ocean reaches the freezing point for salt water, ice begins to grow. When the temperature rises above the freezing point, ice begins to melt. The amount and rates of growth and melt depend on the way heat is exchanged within the sea ice, as well as between the top and bottom of the ice. Below there is seasonal cycle of arctic sea ice growth and melt over one year. The left y-axis represents thickness of sea ice and snow, referenced to the top of the ice.