Glossary

Alchemist

A person who studied an ancient form of science from which chemistry developed. Alchemists sought the philosopher’s stone that turns metals such as lead or iron into gold.

Asteroid

A small rocky body orbiting the Sun. Most asteroids are in the Asteroid Belt, between Mars and Jupiter.

Atmosphere

The layer of gases that surrounds a planet.

Atom

The smallest part of an element that can exist. It consists of a nucleus of protons and neutrons, which is orbited by electrons.

Atomic bomb

A powerful bomb that causes an explosion by releasing the energy in atoms.

Atomic mass

The total number of protons and neutrons that an atom contains.

Cathode ray tube

A tube with a vacuum inside, in which cathode rays produce an image on a screen – used mainly in televisions and computer screens.

CFCs (chlorofluorocarbons)

Chemical compounds formed from chlorine, fluorine, and carbon. CFCs are believed to damage the ozone layer so their use is now restricted.

Chromosome

A thread-like structure in a cell’s nucleus. Chromosomes are made of DNA and contain genes.

Compound

A substance that is formed from the atoms of two or more elements. Water is a compound of hydrogen and oxygen.

Diffraction

The deflection of waves as they pass small obstacles or go through narrow openings.

DNA (deoxyribonucleic acid)

The chemical inside chromosomes that lets parents pass genetic information on to their offspring.

Electron

A tiny particle with a negative electric charge that is found in the empty outer space around an atom’s nucleus.

Element

A basic building block of matter made from identical atoms.

Fossil fuel

A fuel that has formed over millions of years from the remains of living things. Coal, oil, and gas are fossil fuels.

Gene

One of the instructions stored inside cells and required to build and operate an animal’s body or a plant. Genes are passed on from parents to their offspring.

Gravity

A force of attraction between objects found throughout the Universe. The greater the object’s mass, the greater its gravitational pull.

Microchip

A miniature circuit made from thousands or millions of separate electronic components.

Neutron

A particle with no electric charge in the nucleus of an atom.

Nuclear energy

A type of energy released in one of two ways – by joining atoms together to make a larger atom (fusion), or by splitting an atom (fission).

Nucleus

The central part of an atom made from protons and neutrons.

Organism

A living thing consisting of one or more cells.

Palaeontologist

A scientist who studies life forms that existed in former geological periods.

Patent

A government licence that gives the person or company the right of ownership for an invention.

Pesticide

A chemical used to destroy pests that cause damage to crops and plants.

Proton

A particle with a positive electric charge in the nucleus of an atom.

Radioactivity

The disintegration of the nuclei in an atom, causing radiation to be given off.

Seismologist

A scientist who studies earthquakes.

Spacetime

Physicists think that time and space are really closely related. They imagine a combination of space and time called spacetime.

Ultraviolet

A type of electromagnetic radiation with a wavelength shorter than visible light.

X-ray

A type of electromagnetic radiation with a wavelength shorter than ultraviolet radiation.

Zoology

A branch of biology that specializes in the study of animals.