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A glossary of science-related words.

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A dead body, especially one used for dissection.


A transition metal in Group 12 of the periodic table – symbol Cd, atomic number 48.


A pouch connecting the last part of the small intestine, called the ileum, with the first part of the colon, known as the ascending colon.


Partly composed (<50%) of calcium carbonate.


Heating a substance to a high temperature (below its melting point) to allow a chemical reaction to occur. In the case of limestone, the high temperature causes decomposition into carbon dioxide and calcium oxide (lime).


The most common and most stable mineral form of calcium carbonate (CaCO3). It is the main component of chalk, limestone and marble.


When a volcano erupts, a large volume of magma (lava) can spew onto the Earth’s surface. When this large volume of material is removed from beneath the volcano, it can cause it to collapse into the emptied cavern to form a depression. This depression or basin is called a caldera. Some calderas are several kilometres deep and over 25 kilometres wide.


A mass of cells that forms at a wounded surface of a plant. Callus tissue is important when propagating plants because of its ability to generate new plantlets.


A non-SI unit of energy defined as being the amount of energy needed to raise the temperature of 1 gram of water by 1 °C.


A geologic period that lasted from 540–505 million years ago, when there were warm seas and desert land areas. Gondwana emerged and animal life diversified rapidly in a time known as the Cambrian Explosion. Many fossils, notably trilobites, are found from this period. The Cambrian forms the first period of the Palaeozoic Era.


The term for a group of more than 100 diseases in which abnormal cells divide and multiply uncontrollably.


The SI base unit of luminous intensity.


The process of shining a bright light onto the shell of an egg to see the development of the embryo inside.


In ecology, the canopy is one of the uppermost levels of a forest.


A measure of how heavy a diamond or other gemstone is. It is now defined as 200 mg. Carat also has a purity meaning when dealing with the precious metal gold. Pure gold is 24 carats, and 18 carat gold is 18 parts gold and 6 parts other metals, making it 75% pure.


Any of a large group of energy-producing compounds, including sugars and starches, that contain carbon, hydrogen and oxygen.


A non-metal element (C). It is a key component of living things.

carbon cycle

The process by which carbon passes through the natural world. Atmospheric carbon, in the form of carbon dioxide, is taken up by plants and algae during photosynthesis and adsorbed by the oceans. Carbon is also locked underground when decomposing plant and animal waste eventually form fossil fuels such as peat, coal, oil and gas. Carbon is released back into the atmosphere by respiration of living things (in both land and sea) and by combustion of fossil fuels.

carbon dioxide

CO2 is a colourless, odourless, incombustible gas. It is a product of respiration and combustion and is an essential component in photosynthesis.

carbon emission

The amount of carbon released into the atmosphere.

carbon fibre

A material consisting of thin strong crystalline filaments of carbon often used as a strengthening material in composites.

carbon footprint

The total amount of greenhouse gas emissions caused by a defined population such as an organisation, product, activity or system.

carbon monoxide (CO)

A colourless, odourless, very poisonous gas. It is a product of incomplete combustion of carbon-based fuels.

carbon sinks

Natural storage sites for carbon that has been removed from the atmosphere, e.g. oceans absorb carbon dioxide from the air so are therefore called carbon sinks; trees and plant material temporarily store carbon dioxide.


An isotope of carbon that is radioactive and used in carbon dating.

Carboniferous period

The Carboniferous period occurred from about 354 to 290 million years ago. It gets its name from carbon, the basic element in coal and other fossil fuels and refers to rich coal deposits that were found in England.


A substance that can cause cancer.


Any malignant cancer that begins in the cells that cover or line an organ (including skin). Carcinomas invade surrounding tissues and organs and may metastasise (spread) to lymph nodes and other sites.

carcinoma in situ

A malignant tumour that is confined to its original site. Can become malignant if left untreated.

cardiac muscle

The muscle tissue that makes up the heart. One of the three different kinds of muscle in the human body, it has striations like skeletal muscles, but it cannot be controlled voluntarily.

cardiovascular disease

A class of diseases that involve the heart or blood vessels.


Animals that eat other animals.


A category of phytochemicals that give colour to plant parts. For example, carotene is the plant pigment responsible for the orange colour of carrots.


One female reproductive organ of a flower, made up of stigma (receives pollen), style (stalk) and ovary (contains ovules). The collective name for all the carpels in a flower is pistil.


A process in which the rate of a chemical reaction is either increased or decreased by means of a chemical substance known as a catalyst.


A substance that increases the rate of a chemical reaction but is not permanently changed by that reaction.

catalytic converter

A device fitted to the exhaust of a motor vehicle to reduce harmful gases.


An increased thickening and clouding of the lens of the eye that can lead to blurring of the vision or complete loss of vision.


An area that collects all the water that drains to a particular lake, river or reservoir.


An ion with more protons than electrons, giving it a positive charge. For example, positively charged metal ions like Na+ and Ca2+ are cations.

celestial equator

A great circle on the imaginary celestial sphere in the same plane as the Earth’s equator. It is a projection of the terrestrial equator out into space.

celestial sphere

An imaginary hollow globe that encloses the Earth. The concept of the celestial sphere provides a simple way of thinking about the appearance of the stars from Earth without the complication of a more realistic model of the universe.


1. Building block of the body. A human is made of millions of cells, which are adapted for different functions and can reproduce themselves exactly. 2. A simple electrolytic device that enables chemical energy to be transformed into electrical energy.

cell wall

A tough, usually flexible but sometimes fairly rigid layer, that surrounds some types of cells.


A stringy and fibrous carbohydrate (a type of polymer made up of glucose molecules) that is the main constituent of the cell walls of plants, especially important in wood, cotton and hemp etc. Used in the manufacture of paper, cotton and other textiles, kapok, cellophane, rayon, explosives and some pharmaceuticals.


A temperature scale defined by the freezing point (0 °C) and boiling point (100 °C) of pure water. Named after the Swedish astronomer Anders Celsius (1701–1744).


A geologic process in which dissolved minerals precipitate out of solution, gluing particles of sediment together.


Specialised material produced by the root of a tooth. Its main function is to anchor the tooth.


An inorganic non-metal material that can be shaped and hardened by firing at high temperature to form a hard, strong and endurable body.


Latin for little brain. It is a region of the brain that plays an important role in co-ordinating voluntary movement.

cerebrovascular disease

A group of brain dysfunctions related to disease of the blood vessels supplying the brain.


The surface of a material is partially burnt to leave behind unburnt carbon.

chemical energy

The energy store in a substance that can be converted to other forms by chemical reaction.

chemical engineer

Someone who studies the processes and equipment needed for the commercial manufacture of chemicals.

chemical fire retardant

A chemical used as a coating for or a component of a combustible material to reduce its tendency to burn. Also known as fireproofing compound.

chemical marker

In ecology, something in the chemical composition of an organism that can tell us something about the environmental conditions, i.e. food availability or water chemistry during the life of an organism.

chemical reaction

A process in which one or more substances are changed into different substances.


Everything is made up of chemicals. All matter (anything made of atoms) can be called chemicals. They can be in any form – liquid, solid or gas. Chemicals can be a pure substance or a mixture.


A scientist trained in the science of chemistry. Chemists study the composition of matter and its properties.


An organism that is able to make its own food using chemical processes rather than photosynthesis.


The production of carbon-based compounds using the energy released from chemical reactions instead of the energy from sunlight.


The treatment of cancer using chemicals (drugs) that selectively destroy cancerous cells. Most chemotherapy drugs interfere with the ability of cells to grow or multiply.


A naturally occurring long-chain polymer found as the main component in the exoskeletons of invertebrate animals such as crabs, crayfish and shrimps.


A polysaccharide produced from chitin.


The green pigment found in most plants that allows some of the energy from sunlight to be captured and transformed into chemical potential energy.


The organelles present in green plant cells where photosynthesis takes place.

choice chamber

Any biological experiment where a subject can choose one of two chambers based on a test condition.


A hormone produced in the duodenum that reduces appetite, slows down the emptying of the stomach and stimulates the release of bile from the gall bladder.


One of two identical DNA strands (sister chromatids) that exist within a chromosome before cell division.


A structure within the cell nucleus made of a single coiled piece of DNA.


A creamy paste formed after food in the stomach has been mixed and churned with gastric juice over a period of time.

chytrid fungus

A fungus that causes chytridiomycosis, an infectious disease that has now affected almost every frog population in the world.

ciliary muscle

A ring of smooth muscle fibres that is responsible for changing the shape of the crystalline lens in the eye.

circalittoral zone

The area below the infralittoral zone where light is still able to penetrate through the water. An area of coast dominated by oysters and so on.

circuit components

The parts that make up an electrical circuit such as batteries, resistors and diodes.


Located around a polar region (e.g. a water current travelling around the South Pole is called a circumpolar current).


A division used in the Linnean system of classification or taxonomy.


The process of ordering living things into a system that allows scientists to identify them. Modern science uses the Linnaean system of classification where organisms are grouped based on what species they are most closely related to.


A naturally occurring fine-grained material formed from the chemical weathering of feldspar minerals found in rocks.


A mineral is said to have cleavage if part of the crystal breaks when forcibly hit and the broken piece retains the crystal shape. A mineral that never produces any crystallised fragments when broken off by hitting has no cleavage.


In earthworms, the glandular ring or saddle found on mature earthworms. After mating, the clitellum secretes a cocoon of eggs.


In biology, the process of producing similar populations that are genetically identical.


When a substance groups small particles together to form larger particles or clots.


Individual plates of calcite arranged around a single-celled marine alga to give protection. Chalk deposits are made up of fossilised coccoliths.


Structure within the inner ear that detects sound.

coefficient of performance (COP)

A measure of the performance of a heat pump. Conventional heat pumps have COPs of 2–5, which means they transfer 2–5 times as much energy as they consume.

coelomic fluid

Fluid transporting gases, wastes and nutrients through the body of an earthworm. It also surrounds and cushions the digestive system.


In earthworms, the hollow space between the muscles and the digestive system. This is filled with coelomic fluid.

cohesin proteins

Proteins that regulate chromosome structure during cell division and play a role in regulating gene expression.

cohesive force

The attractive force that holds together individual liquid molecules.

cold adapted

Being adjusted to a cold living environment.

cold seep

A place on the seafloor where cold methane-rich water escapes. Cold seeps occur most often at tectonic plate boundaries. Carbonate deposits and specialised communities of organisms are often found at these sites.


The action of working with someone to produce something. Collaboration has mutual benefits for both parties. Collaboration can occur between individuals working in a team. It can also describe the way in which individuals or organisations work together on a project. In this case, the collaboration may only be a small part of the individuals’ or organisations’ overall goals and responsibilities.


Any of various tough, fibrous proteins found in bone, cartilage, skin, and other connective tissue. Collagens have great strength and their job is to form strong insoluble fibres that connect cells. Collagen is converted into gelatin when it is boiled.


When two or more particles briefly come into contact with each other.


A mixture of very small particles, 1–1000 nm, suspended in another material. Milk is a colloid of fat in watery liquid.


That part of the large intestine between the caecum and rectum. It consists of four sections: the ascending colon, the transverse colon, the descending colon and the sigmoid colon.

combustible energy sources

Capable of igniting and burning (for example, wood, oil and gas).


A chemical reaction that involves the process of burning.


A close association of two different species where one benefits and the other is neither harmed nor helped.


A geologic process in which sediments are progressively buried by more sediment, causing them to press together under their own weight, reducing their thickness.


A pure substance made up of two or more different elements chemically combined.

compression stress

A stress state where a body of material is compacted or squashed. resulting in a decrease in volume. Also called compressive stress.

computational modelling

Using a computer to make scientific models for testing. This is particularly useful if it is difficult to test the science in reality (for example, in testing fire behaviour).

concave mirror

A mirror in which the reflective surface curves inwards away from the light source. Incident light is reflected inwards to one focal point. A concave mirror can be used to focus light.


A change of molecular state where gas becomes liquid due to cooling.

conducting polymer

A plastic that can conduct electricity.


1. Heat flow or transfer through a substance from a higher to a lower temperature. 2. Flow of electric charges through a material in response to an electric field.


A material or element that allows free movement of electrons and therefore allows easy flow of electricity.

cone cell

A type of photoreceptor cell found in the retina of the eye. Three types of cone cells have been identified, and these provide the eye’s colour sensitivity.

cone volcano

A type of volcano that includes stratovolcanoes. Formed by the accumulation of many different lava flows and pyroclastic deposits. Associated with andesite rocks.


The protection, preservation and careful management of a species, habitat, artifact or taonga

constant speed

When the speed of an object such as a cyclist stays the same. If forces are balanced, the cyclist will travel at a constant speed.


An area of the night sky that contains a group of stars that seems to form a certain shape or picture.


An organism that eats producers or other consumers.


An unwanted substance found in an environment, for example, a polluting chemical in a river.

continental drift

A theory of land movement proposed by Alfred Wegener. All land is on massive continental plates that move due to the currents in the magma under the Earth’s crust.


A muscle getting shorter and pulling.


Part of a scientific experiment in which no treatment has been applied in order to see whether there are any detectable differences to the experiment that did receive a treatment.


A method of moving heat energy. Found only in gases and liquids. Convection currents move heat from one location to another.

convection current

A current that occurs when fluid is unevenly heated so that part of the fluid rises, then cools and then sinks, producing the circular movement. This effect is caused by changes in the density of a substance when heated or cooled.

convergent boundaries

Tectonic plate boundaries, where crust is destroyed as one plate dives under another.

convergent evolution

Occurs when unrelated organisms develop similar adaptations for similar environmental niches.

converging muscles

Where muscles come together at one point.

converging plate boundaries

The area where two plate boundaries meet and collide. These boundaries can occur between two continental plates, two oceanic plates or between continental and oceanic plates. This is how mountain ranges such as the Southern Alps are created.

convex mirror

A mirror in which the reflective surface curves outwards towards the light source. Incident light is reflected outwards. Convex mirrors provide a wider field of view and are often used as security mirrors.


A transition metal in Group 11 of the periodic table – symbol Cu, atomic number 29.


Fossilised excrement (also called fossilised dung, faeces or poo). Analysis of coprolites for plant and animal fragments gives scientists information about the diet and environment of ancient animals.


The transparent front part of the eye that contributes substantially to the eye’s ability to focus light onto the retina.


The outer layer of the Sun’s atmosphere. It is visible to the naked eye as a white halo during a solar eclipse when the photosphere and chromosphere have been completely occluded.

coronal mass ejection (CME)

An explosive release from the Sun’s outer atmosphere of a massive cloud of billions of tonnes of plasma material.


Finding out the relationship between things. In geology, correlation involves trying to match rocks or fossils of the same age between different locations.


The cerebral cortex, or just cortex, is often referred to as grey matter because the nerves it is made up of lack the insulation that makes other parts of the brain appear white. It covers the outer portion of the cerebrum and cerebellum. In humans, it is 2–4 mm thick and plays a central role in many complex brain functions including memory, attention, perceptual awareness, 'thinking', language and consciousness. The cerebral cortex consists of folded bulges that create deep furrows. The folds in the brain add to its surface area and therefore increase the amount of grey matter and the quantity of information that can be processed.

cosmic dust

Clouds of fine solid particles of matter in interstellar space.


A scientist who studies the origins and structure of the universe.


Unit of electric charge derived from the ampere. It is defined as the charge transported by a steady current of 1 ampere in 1 second.

cow yard

An area that holds cows prior to milking.

creatine phosphate

A high energy phosphate molecule that is stored in cells and can be used to re-synthesise ATP as soon as the ATP has been used.


The third and last geological time period in the Mesozoic era, from 140 million to 65 million years ago. This time period is marked by the main development and subsequent extinction of The third and last geological period of the Mesozoic era. It lasted from 145 to 65 million years ago.

critical consumer

Someone who uses their understanding of scientific concepts and processes to actively analyse and evaluate texts and media to make informed personal decisions.

critical temperature

The temperature below which a material has zero electrical resistance. The critical temperature for mercury is -269 °C.

critically endangered

Extremely high risk of extinction in the wild (International Union for Conservation of Nature ranking).


A compartment of muscle tissue that birds use to store and soften their food before it moves on to be processed by the gizzard.


The part of a myosin filament in muscle that is involved in the sliding filament model of muscle contraction.


The transfer of pollen from one flower to another flower on a different plant. Genetic material becomes mixed, resulting in variation in the population and a better chance of survival.


The process whereby people invest in a company that is not listed on a stock market in exchange for shares in that company.


The outermost layer of the Earth. Estimated to be between 5–50 km thick. Made of solid rock of all types (metamorphic, igneous and sedimentary).


A large group of arthropods, which includes animals such as crabs, lobsters, crayfish, shrimp, krill and barnacles.


From the Greek cryos (cold) and genesis (birth), a geologic period that lasted from 850–635 million years ago. The Cryogenian forms the second geologic period of the Neoproterozoic Era. The greatest ice ages, between 2 and 4 events that may have covered the entire planet, occurred during this period, the greatest being the Marinoan glaciation.


The cryosphere covers all the frozen water and soil on Earth. This includes snow, ice, sea ice, ice shelves, glaciers and permafrost. The predominant mass of the cryosphere is located in the poles, but it also exists in places far away from the cold poles, for example, the snow on Mount Kilimanjaro in Africa or glaciers like Franz Josef Glacier here in New Zealand. The cryosphere is dynamic, expanding and contracting with seasonal variations.

crystal mush

A term describing the consistency of magma as it interacts with the crust under a volcano.

crystalline lens

The internal part of the eye that helps to focus incoming light rays onto the back of the eye. Its shape can be altered by a set of muscles and ligaments allowing the eye to accommodate for near or far vision.


The length of the forearm from the elbow to the tip of the middle finger.


A plant variety that has been specially selected and/or improved using horticultural techniques for cultivation.


Gradually building up.


The flow of electric charge through a conductor.


A major grouping within bacteria; produce carbohydrates and oxygen through photosynthesis. Found in freshwater and marine environments and may be solitary or colonial. Used to be referred to as the blue green algae.


The scientific study of the structure and function of cells.


All of the contents of a cell outside of the nucleus.