A1.1 Water

Covalent bond

a bond between atoms in which pairs of electrons are shared

Polar molecule

a molecule where there is an unequal distribution of electrical charge one end is slightly positive and the other end is slightly negative

Hydrogen bond

a weak attractive intermolecular force; a hydrogen atom in a molecule is attracted to an electronegative atom, such as oxygen, in a different molecule

Cohesion

force by which individual molecules of the same type attract and associate

Surface tension

property of the surface of a liquid that allows it to resist an external force, due to the cohesion between water molecules.

Viscosity

a measure of a fluid’s resistance to flow

Adhesion

the force by which individual molecules stick to surrounding materials and surfaces

Hydrophilic

attracted to water

Capillary tubes

channels with a very small internal diameter

Capillary action

the tendency of a liquid to move up against gravity when confined within a narrow tube, also known as capillarity

Solute

dissolved molecule or ion in a solution

Solvent

a liquid in which another substance can be dissolved

Hydrophobic

repelled by water

Buoyancy

the ability of any fluid to provide a vertical upwards force on an object placed in or on it

Thermal conductivity (k)

the measure of how easily heat flows through a specific type of material

Specific heat capacity

the amount of energy required to raise the temperature of 1 kg of a substance by 1 celsius

Goldilocks zone

also known as the ‘habitable zone’; the area around a star where it is not too hot or too cold for liquid water to exist on the surface of surrounding planets