Ground-up limestone, rich in calcium carbonate, that is spread on pasture and added to soils to increase the pH of the soil. It also provides a source of calcium and improves the uptake by plants of major plant nutrients.

Greek for ‘out of the Earth’. Earthworms occupying the anecic niche live as far as 3 metres below the soil surface.

1. The layer of gas around the Earth. 2. (atm) A non-SI unit of pressure equivalent to 101.325 kPa.

Finding the actual dates of geological or archaeological objects. Normally expressed as calendar years ago.

The lowest possible temperature, equivalent to -273.15 °C. Used as the zero point of the Kelvin temperature scale.

When the incident light energy striking a material object is completely taken in by the atoms/molecules that make up the structure of the object.

The rate at which an object speeds up, slows down or changes direction.

A device to measure acceleration (the rate at which an object’s velocity changes).

The process by which the eye changes the shape of the crystalline lens to maintain a clear image of an object as its distance from the eye changes.

In science, accuracy indicates the closeness of the measurements to the true or accepted value.