IB Bio Chapter 1: Water

Adhesion

Attraction between molecules of different substances (e.g., water sticking to glass).

Anion

A negatively charged ion (gains electrons).

Asteroid

A small rocky body orbiting the Sun, mostly found in the asteroid belt between Mars and Jupiter.

Atom

The smallest unit of matter that retains the properties of an element; made of protons, neutrons, and electrons.

Buoyancy

The upward force exerted by a fluid on an object placed in it (explains why things float)

Capillary Action

Movement of liquid within narrow spaces without external forces, caused by cohesion and adhesion (e.g., water climbing up plant roots).

Cation

A positively charged ion (loses electrons).

Cohesion

Attraction between molecules of the same substance (e.g., water molecules sticking to each other)

Condensation

Change of matter from gas to liquid (e.g., water droplets forming on a cold glass)

Covalent Bond

A chemical bond where two atoms share electrons

Electron

A negatively charged subatomic particle found outside the nucleus of an atom

Enzyme

A protein that speeds up (catalyzes) chemical reactions in living organisms.

Extraplanetary

Located or taking place beyond Earth but still within our solar system (e.g., on Mars or an asteroid).

Extraterrestrial

Anything originating outside Earth (life, matter, or objects from space).

Goldilocks Zone

The habitable zone around a star where conditions are 'just right' for liquid water and possibly life.

Hydrogren Bond

A weak bond between slightly positive hydrogen atoms and slightly negative atoms (such as oxygen in water).

Hydrophilic

'Water-loving'; substances that dissolve easily in water.

Hydrophobic

'Water-fearing'; substances that do not mix well with water (e.g., oils).

Insoluble

A substance that cannot dissolve in a particular solvent (e.g., sand in water).

Ion

An atom or molecule that has gained or lost electrons, giving it a charge.

Ionic Bond

A chemical bond formed by the attraction between oppositely charged ions.

Netron

A neutral (no charge) subatomic particle found in the nucleus of an atom.

Non-polar Covalent Bond

A covalent bond where electrons are shared equally between atoms.

Polar Covalent Bond

A covalent bond where electrons are shared unequally, creating partial positive and negative charges.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Physical Property

A characteristic of matter that can be observed without changing its identity (e.g., density, color, melting point).

Solute

A substance that can dissolve in a particular solvent (e.g., sugar in water).

Solvent

A substance that does dissolving (e.g., water dissolves polar molecules).

Solvation

The process of surrounding solute particles with solvent molecules during dissolving.

Specific Heat Capacity

The amount of energy required to raise the temperature of 1 gram of a substance by 1°C. Water has high heat capacity.

Surface Tension

The 'skin-like' effect on the surface of a liquid caused by cohesion of molecules.

Thermal Conductivity

The ability of a substance to transfer heat.

Viscosity

A measure of a fluid’s resistance to flow (honey has high viscosity, water has low viscosity).

Water

A polar molecule (H₂O) essential for life, with unique properties such as cohesion, adhesion, high specific heat, and solvent abilities.