Additional Science Glossary

gloassry words and definition

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Acceleration
Change of velocity per second (in m/s2)
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Acid
The chemical opposite of an alkali. when dissolved in water, its solution has a pH number less than 7. acids are proton H+ donors.
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Activation Energy
The minimum energy needed to start off a reaction.
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Active Site
The site on an enzyme where the reactants bind.
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Algal cells
The cells of algae, single-celled or simple multicellular organisms, which can photosynthesis but are not plants.
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Alkali
Its solution has a pH number more than 7, produce OH- hydroxide ions.
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Allele
A version of a particular gene.
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Alpha radiation
Alpha particles, each composed of two protons and two neutrons, emitted by unstable nuclei.
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Alternating Current
Electric current in a circuit that repeatedly reverses its direction.
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Amino Acid
The building block of protein.
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Amylase
The enzyme made in the salivary glands and the pancreas that speeds up the breakdown of starch into simple sugars.
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Anhydrous
Describes a substance that does not contain water.
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Aqueous solution
The mixture made by adding a soluble substance to water.
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Atomic number
The number of protons (which equals the number of electrons) in an atom.
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Attract
To cause to move nearer.
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Bacterial colony
A population of billions of bacteria grown in culture.
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Base
The oxide, hydroxide or carbonate of a metal that will react with an acid, forming salt as on of the products. (If a base dissolves in water it is called an alkali). Bases are proton (H+ ion) acceptors.
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Beta radiation
Beta particles that are high-energy electrons created in and emitted from unstable nuclei
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Bile
Yellowy-green liquid made in the liver and stored in the gall bladder. It is released into the small intestine and emulsifies fats.
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Biological detergent
Washing detergent that contains enzymes.
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Biomass
Biological material from living or recently living organisms.
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Black Dwarf
A star that has faded out and gone cold.
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Black hole
An object in space that has so much mass that nothing, not even light, can escape from its gravitational filed.
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Braking Distance
The distance traveled by vehicle during the time its brakes act.
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Cable
Two or three insulated wires surrounded by an outer layer of rubber or flexible plastic.
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Carbohydrase
Enzyme that speeds up the breakdown of carbohydrates.
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Carrier
Individual who is heterozygous for a faulty allele that causes a genetic disease in the homozygous form.
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Catalyst
A substance that speeds up a chemical reaction. At the end of the reaction the catalyst remains chemically unchanged.
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Cell membrane
The membrane around the contents of a cell that controls what moves in and out of a cell.
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Cell wall
A rigid structure that surrounds the cells of living organisms apart from animals.
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Cellulose
A big carbohydrate molecule that makes up plant and algal cell walls.
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Chain Reaction
Reactions in which one reaction causes further reactions, which in turn cause further reactions etc. A nuclear chain reaction occurs when fission neutrons cause further fission, so more fission neutrons are released, producing further fission.
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Chlorophyll
The green pigment contained in the chloroplasts.
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Chloroplast
The organelle in which photosynthesis takes place.
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Chromatography
The process whereby small amounts of dissolved substances are separated by running a solvent along a material such as absorbent paper.
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Circuit breaker
An electromagnetic switch that opens and cuts the current off if too much current passes through it.
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Collision Theory
An explanation of chemical reactions in terms of reacting particles colliding with sufficient energy for a reaction to take place.
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Concentration gradient
The gradient between an area where a substance is at a high concentration and an area where it is at a low concentration.
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Conservation of momentum
In a closed system, the total momentum before an event is equal to the total momentum after the event. Momentum is conserved in any collision or explosion provided no external forces act on the objects that collide or explode.
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Covalent Bonding
The attraction between two atoms that share one or more pairs of electrons.
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Crumple zone
Region of a vehicle designed to crumple in a collision to reduce the force on the occupants.
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Cystic Fibrosis
A genetic disease that affects the lungs, digestive and reproductive systems. It is inherited through a recessive allele
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Cytoplasm
The water-based gel in which the organelles of all living cells are suspended.
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Deceleration
Change of velocity per second when an object slows down.
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Delocalised electron
Bonding electron that is no longer associated with any one particular atom.
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Denatured
Change the shape of any enzyme so it can no longer speed up a reaction.
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Differentiate
Specialise for a particular function.
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Diffusion
The net movement of particles of a gas or a solute from an area of high concentration to an area of low concentration (along a concentration gradient).
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Digestion
Breaking down into small molecules by the digestive enzymes.
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Digestive juice
The mixture of enzymes and other chemicals produced by the digestive system.
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Digestive system
The organ system running from the mouth to the anus where food is digested.
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Diode
Electrical device that allows current flow in one direction only.
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Direct Current
Electric current in a circuit that is in one direction only.
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Directly Proportional
A graph will show this if the line of best fit is a straight line through the origin.
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DNA fingerprint
Pattern produced by analysing the DNA which can be used to identify an individual.
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Dominant
The characteristic that will show up in the offspring even if only one of the alleles is inherited.
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Dot and cross diagram
A drawing to show the arrangement of the outer shell electrons only of the atoms or ions in a substance.
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Drag force
A force opposing the motion of an object due to fluid (e.g. air) flowing past the object as it moves.
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Elastic
A material is elastic if it is able to regain its shape after it has been squashed or stretched.
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Elastic potential energy
Energy stored in an elastic object when work is done to change its shape.
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Electrolyte
A liquid, containing free-moving ions, that is broken down by electricity in the process of electrolysis.
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Electron
A tiny particle with a negative charge. Electrons orbit the nucleus in atoms or ions.
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Empirical formula
The simplest ratio of elements in a compound.
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Endothermic
A reaction that takes in energy from the surroundings.
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Enzyme
A protein molecule that acts as a biological catalyst.
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Epidermal tissue
The tissue of the epidermis- the outer layer of an organism.
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Epithelia tissue
Tissue made up of relatively unspecialised cells that line the tubes and organs of the body.
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Exothermic
A reaction that gives out energy to the surroundings.
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Extinction
Extinction is the permanent loss of all the members of a species.
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Fatty acid
Building block of lipids.
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Fermentation
The reaction in which the enzymes in yeast turn glucose into ethanol and carbon dioxide.
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Force
A force can change the motion of an object (in newtons,N).
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Frequency(of an alternating current)
The number of complete cycles an alternating current passes through each second. The unit of frequency is the hertz (Hz).
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Fructose syrup
A sugar syrup
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Fullerene
Form of the element carbon that can form a large cage-like structure, based on hexagonal rings of carbon atoms.
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Fuse
A fuse contains a thin wire that melts and cuts the current off if too much current passes through it.
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Gamma radiation
Electromagnetic radiation emitted from unstable nuclei in radioactive substances.
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Gas chromatography
The process of separating the components in a mixture by passing the vapours through a column and detecting them as they leave the column at different times.
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Genetic disorder
Disease which is inherited
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Genetic material
The DNA which carries the instructions for making a new cell or a new individual.
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Geographical isolation
This is when two populations become physically isolated by a geographical feature.
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Giant covalent structure
A huge 3-D network of covalently bonded atoms (e.g. the giant lattice of carbon atoms in diamond or graphite).
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Giant lattice
A huge 3-D network of atoms or irons (e.g. the giant ionic lattice in sodium chloride).
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Giant structure
See giant lattice.
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Glandular tissue
The tissue which makes up the glands and secretes chemicals, e.g. enzymes, hormones.
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Glucose
A simple sugar
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Glycerol
Building block of lipids
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Glycogen
Carbohydrate store in animals, including the muscles, liver and brain of the human body.
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Gradient (of a straight line graph)
Change of the quantity plotted on the y-axis divided by the change of the quantity plotted on the x-axis.
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Gravitational field strength,g
The force of gravity on an object of mass 1kg (in newtons per kilogram, N/kg).
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Gravitational potential energy
Energy of an object due to its position in a gravitational field. Near the Earth's surface, change of GPE (in joules, J = weight (in newtons, N) x vertical distance moved (in metres, m).
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Half equation
An equation that describes reduction (gain of electrons) or oxidation (loss of electrons), such as the reactions that take place at the electrodes during electrolysis. For example: Na+ + e- ->Na.
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Half-life (of a radioactive isotape)
Average time taken for the number of nuclei of the isotope (or mass of the isotope)in a sample to halve.
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High mass star
A star that has a much greater mass than the Sun.
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Hooke's law
The extension of a spring is directly proportional to the forse applied, provided its limit of proportionality is not exceeded.
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Hydrated
Describes a substance that contains water in its crystals, e.g. hydrated copper sulfate.
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Hydroponics
Growing plants in water enriched by mineral ions rather than soil.
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Hypothesis
A proposal intended to explain certain facts or observations.
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Inert
Unreactive
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Insoluble molecules
Molecules which will not dissolve in a particular solvent such as water.
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Intermolecular force
The attraction between the individual molecules in a covalently bonded substance.
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Ion
A charged particle produced by the loss or gain of electrons.
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Ionic bonding
The electrostatic force of attraction between positively and negatively charged ions.
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Ionisation
Any process in which atoms become charged.
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Isomerase
An enzyme which converts one form of a molecule into another.
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Isotape
Atom that has the same number of protons but different number of neutrons, i.e. it has the same atomic number but different mass number.
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Kidney tubule
The structure in the kidney where substances are reabsorbed back into the blood.
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Kinetic energy
Energy of a moving object due to its motion; kinetic energy (in joules, J) = mass (in kilograms, kg) x (speed)2 (in m2/s2).
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Lactic acid
One product of anaerobic respiration. It builds up in muscles with exercise. Important in yogurt and cheese making processes.
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Light energy
Energy in the form of light.
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Light microscope
An instrument used to magnify specimens using lenses and light.
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Limiting factor
Factor which limits the rate of a reaction e.g. temperature, pH, light levels, (photosynthesis).
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Limit of proportionality
The limit for Hooke's law applied to the extension of a stretching spring.
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Lipase
Enzyme which breaks down fats and oils into fatty acids and glycerol.
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Lipid
Oil or fat.
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Live wire
The wire of a main ciruit that has a potential that alternates from positive to negative and back each cycle.
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Low mass star
A star that has a much smaller mass than the Sun.
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Macromolecule
Giant covalent structure.
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Main sequence star
The main stage is the life of a star during which it radiates energy because of fusion of hydrogen nuclei in its core.
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Mass
The quantity of matter in an object; a measure of the difficulty of changing the motion of an object (in kilograms,kg).
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Mass number
The number of protons plus neutrons in the nucleus of an atom.
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Mass spectrometer
A machine that can be used to analyse small amounts of a substance to identify it and to find its relative molecular mass.
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Mean
The arithmetical average of a series of numbers.
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Median
The middle value in a list of data.
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Meiosis
The two-stage process of cell division which reduces the chromosome number of the daughter cells. It is involved in making the gametes for sexual reproduction.
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Mesophyll tissue
The tissue in a green plant where photosynthesis takes place.
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Mineral iron
Chemical needed in small amounts as part of a balanced diet to keep the body healthy.
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Mitochondria
The site of aerobic cellular respitation in a cell.
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Mitosis
Asexual cell division where two identical cells are formed.
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Mode
The number which occurs most often in a set of data.
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Moderator
A solid or liquid used in a nuclear reactor to slow fission neutrons down so they can cause further fission.
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Mole
The amount of substance in the relative atomic or formula mass of a substance in grams.
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Molecular formula
The chemical formula that shows the actual numbers of atoms in a particular molecule (e.g. C2H4).
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Molecular ion peak
The peak on the mass spectrum of a substance which tells us the relative molecular mass of the substance. The peak is produced by the heaviest positive ion shown on the mass spectrum.
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Momentum
This equals mass (in kg) x velocity (in m/s). The unit of momentum is the kilogram metre per second (kg m/s)
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Multicellular organism
An organism which is made up of many different cells which work together. Some of the cells are specialised for different functions in the organism.
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Muscular tissue
The tissue which makes up the muscles. It can contract and relax.
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Nanoscience
The study of very tiny particles or structures between 1 and 100 nanometres in size - where 1 nanometre = 10.9 metres
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Net movement
The overall movement of....
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Neutral
A solution with a pH value of 7 which is neither acidic nor an alkaline. Alternatively, something that carries no overall electrical charge - neither positively or negatively charged.
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Neutralisation
The chemical reaction of an acid with a base in which they cancel each other out, forming a salt and water. If the base is a carbonate or hydrogen carbonate, carbon dioxide is also produced in the reaction.
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Neutral wire
The wire of a mains circuit that is earthed at the loval substation so its potential is close to zero.
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Neutron
A dense particle found in the nucleus of an atom. It is electrically neutral, carrying no charge
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Neutron star
The highly compressed core of a massive star that remains after a supernova explosion.
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Nitrate ion
Ion which is needed by plants to make proteins.
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Nuclear fission
The process in which certain nuclei (uranium-235 and plutonium - 239)split into two fragments, releasing energy and two or three neutrons as a result.
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Nuclear fission reactor
A reactor that releases energy as a result of nuclear fission inside it.
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Nuclear fusion
The process in which small nuclei are forced together so they fuse with each other to form a larger nucleus.
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Nucleus (of a cell)
An organelle found in many living cells containing the genetic information.
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Nucleus (of an atom)
The very samll and dense central part of an atom which contains protons and neutrons.
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Ohm's Law
The current through a resistor at constant temperaure is directly proprotional to the potential difference across the resistor.
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Ohmic conductor
A conductor that has a constant resistance and therefore obeys Ohm's law.
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Optic nerve
The nerve carrying impulses from the retina of the eye to the brain.
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Organ
A group of of different tissues working together to carry out a particular function.
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Organ system
A group of organs working together to carry out a particular function.
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Oscilloscope
A device used to display the shape of an electrical wave.
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Ova
The female sex cells, eggs.
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Oxidation
The reaction when oxygen is added to a substance (or when electrons are lost).
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Oxygen debt
The extra oxygen that must be taken into the body after exercise has stopped to complete the aerobic respiration of lactic acid.
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Parallel
Components connected in a circuit so that the potential difference is the same across each one.
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Percentage yield
The actual mass of product collected in a reaction divided by the maximum mass that could of been formed in theory, multiplied by 100.
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Permanent vacuole
A space in the cytoplasm filled with cell sap which is there all the time.
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pH scale
A number which shows how strongly acidic or alkaline a solution is. Acids have a pH of less than 7 (pH 1 is strongly acidic). Alkalis have a pH value above 7 (pH 14 is stronlgy alkaline). A neutral liquid has a pH value of 7.
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Phloem tissue
The living transport tissue in plants which carries sugars around the plant.
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Planet
A large object that moves in an orbit round a star. A planet reflects light from the star and does not produce its own light.
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Plasmid
Extra circle of DNA found in bacterial cytoplasm.
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Plug
A plug has an insulated case and is used to connect the cable from an appliance to a socket.
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Polydactyly
A genetic condition inherited through a dominant allele which results in extra fingers and toes.
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Polymer
A substance made from very large molecules made up of many repeating units e.g. poly(ethene).
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Polytunnel
Large greenhouse made of plastic.
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Potential difference
A measure of the work done or energy transferred to the lamp by each coulomb of charge that passes through it. The unit of potential difference is the volt (V).
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Power
The energy transformed or transferred per second. The unit of power is the watt (W)
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Precipitate
An insoluble solid formed by a reaction taking place in a solution.
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Precision
A precise set of repeat readings will be closely grouped together.
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Predator
Animal which preys on other animals for food
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Protease
An enzyme which breaks down proteins.
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Protein synthesis
The process by which proteins are made on the ribosomes based on information from the genes in the nucleus.
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Proton
A tiny positive particle found inside the nucleus of an atom.
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Prostar
The concentration of dust clouds and gas in space that forms a star.
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Quadrat
A piece of apparatus for sampling organisms in the field.
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Quantitative sampling
Sampling which records the number of organisms rather than just the type.
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Radiation dose
Amount of ionising radiation a person recieves.
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Random
Cannot be predicted and has no recognisable cause.
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Range
The maximum and minimum values of the independent or dependent variables; important in ensuring that any pattern is detected.
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Recessive
The characteristic that will show up in the offspring only if both of the alleles are inherited.
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Red Giant
A star that has expanded and cooled, resulting in it becoming red and much larger and cooler than it was before it expanded.
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Reduction
A reaction in which oxygen is removed (or electrons are gained).
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Relative atomic mass, Ar
The average mass of an element compared with carbon-12 (which is given a mass of exactly 12). The average must take into account the proportions of the naturally occurring isotopes of the element.
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Relative formula mass, Mr
The total of the relative atomic masses, added up in the ratio shown in the chemical formula, of a substance.
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Repeatability (of data)
We can improve the accuracy of data by repeating measurements and calculating the mean (having re-tested or discarded any anomalous results).
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Reproducibility (of data)
The consistency of data that is collected when different people carry out the same investigation.
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Residual Current Circuit Breaker (RCCB)
An RCCB cuts off the current in the live wire when it is different from the current in the neutral wire.
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Resistance Ω
Resistance (in ohms) = potential difference (in volts, V) ÷ current (in amperes, A).
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Resolution
This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.
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Respiration
The process by which food molecules are broken down to release energy for the cells.
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Resultant force
The combined effect of the forces acting on an object.
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Retention time
The time it takes a component in a mixture to pass through the column during gas chromoatography.
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Reversible reaction
A reaction in which the products can re-form the reactants.
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Ribosome
The site of protein synthesis in a cell.
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Salivary gland
Gland in the mouth which produces saliva containing the enzyme amylase.
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Salt
A salt is a compound formed when some or all of the hydrogen in an acid is replaced by a metal (or by an ammonium ion). For example, potassium nitrate, KNO3 (from nitric acid)
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Sample size
The size of a sample in an investigation
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Series
Components connected in a circuit so that the same current that passes through them, are in series with eachother.
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Sex chromosome
The chromosome which carries the information about the sex of an individual.
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Shape memory alloy
Mixture of metals which respond to changes in temperature.
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Small intestine
The region of the digestive system where most of the digestion of the food takes place.
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Socket
A mains socket is used to connect the mains plug of a mains appliance to the mains circuit.
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Specialised
Adapted for a particular function.
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Speciation
The formation of a new species.
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Speed
Distance moved ÷ time taken.
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State symbol
The abbreviations used in balanced symbol equations to show if reactants and products are solid (s), liquid (l), gas (g) or dissolved in water, aqueous (aq).
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Static electricity
Charge 'held' by an insulator or an insulated conductor.
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Stem cell
Undifferentiated cell with the potential to form a wide variety of different cell types.
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Stopping distance
Thinking distance + braking distance.
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Substrate
The material or chemical on which an enzyme acts.
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Supergiant
A massive star that becomes much larger than a giant star when fusion of helium nuclei commences.
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Supernova
The explosion of a massive star after fusion in its core ceases and the matter surrounding its core collapses on to the core and rebounds.
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Terminal velocity
The velocity reached by an object when the drag force on it is equal and opposite to the force making it move.
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Therapeutic cloning
Cloning by transferring the nucleus of an adult cell to an empty egg to produce tissues or organs which could be used in medicine.
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Thermal decomposition
The breakdown of a compound by heat.
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Thermosetting polymer
Polymer that can form extensive cross-linking between chains, resulting in rigid materials which are heat-resistant.
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Thermosoftening polymer
Polymer that forms plastics which can be softened by heat, then remoulded into different shapes as they cool and set.
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Thinking distance
The distance travelled by the vehicle in the time it takes the driver to react.
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Three-pin plug
A three-pin plug has a live pin, a neutral pin and an earth pin. The earth pin is used to earth the metal case of an appliance so the case cannot become live.
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Time base control
An oscilloscope control used to space the waveform out horizontally.
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Tissue
A group of specialised cells all carrying out the same function.
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Transect
A measured line or area along which ecological measurements (e.g. quadrants) are made.
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Tuber
Modified part of a plant which is used to store food in the form of starch.
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Universal indicator
A mixture of indicators which can change through a range of colours depending on the pH of a solution. Its colour is matched to a pH number using a pH scale. It shows how strongly acidic or alkaline liquids and solutions are.
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Valid
Suitability of the investigation procedure to answer the question being asked.
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Variable
Physical, chemical or biological quantity or characteristic.
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Variable - categoric
Categoric variables have values that are labels. For example, names of plants or types of material.
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Variable - continuous
Can have values (called a quantity) that can be given by measurement (e.g. light intensity, flow rate, etc.).
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Variable - dependent
The variable for which the value is measured for each and every change in the independent variable.
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Variable - independent
The variable for which values are changed or selected by the investigator.
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Variegated
Having different colours, e.g. a green and white leaf.
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Velocity
Speed in a given direction (in metres/second, m/s).
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Volt (V)
The unit of potential difference, equal to energy transfer per unit charge in joules per coulomb.
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Weight
The force of gravity of an object (in Newtons, N).
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White dwarf
A star that has collapsed from the red giant stage to become much hotter and denser than it was.
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Work
Energy transferred by a force, given by: Work done (in Joules, J) = force (in newtons, N) x distance moved in the direction of the force (in metres, m).
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Xylem tissue
The non-living transport tissue in plants which transports water around the plant.
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Y-gain control
An oscilloscope control used to adjust the height of the waveform.
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Yield
The actual mass of a product collected in a reaction.
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Accuracy
This tells us how near the true value a measurement is.
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Activity
Number of atoms of a radioactive substance that decay each second.
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Aerobic respiration
Breaking down food using oxygen to release energy for the cells.
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Anaerobic respiration
Breaking down food without oxygen to release energy for the cells.
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Anomaly
Result that does not match the pattern seen in the other data collected or is well outside the range of other repeat readings. It should be retested and if necessary discarded.
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Asexual budding
A form of sexual reproduction where a complete new individual forms as a bud on the parent organism e.g. yeast, hydra
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Brine
A solution of sodium chloride in water.
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Charging by friction
The process of charging certain insulating materials by rubbing with a dry cloth, causing electrons to transfer between the material and the cloth.
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Compound
A substance made when two or more elements are chemically bonded together. For example, water (H20) is a compound made from hydrogen and oxygen.
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Control rod
Metal rod (made from boron or cadmium) used to absorb excess fission neutrons in a nuclear reactor so that only one fission on average goes on to produce a further fission.
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Coolant
Fluid in a circuit pumped through the core of a nuclear reactor to remove energy to a heat exchanger.
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Earthed
Connected to the ground by means of a conducting lead or wire.
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Electric current
Flow of electric charge. The size of an electric current (in amperes, A) is the rate of flow of charge.
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Electrolysis
The breakdown of a substance containing ions by electricity.
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Electronic structure
A set of numbers to show the arrangement of electrons in their shells (or energy levels) e.g. the electronic structure of a potassium atom is 2,8,8,1.
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Electron microscope
An instrument used to magnify specimens using a beam of electrons.
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Electroplating
The process of depositing a thin layer of metal on an object during electrolysis.
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Element
A substance made up of only one type of atom. An element cannot be broken down chemically into any simpler substance.
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Emulsifies
Breaks down into tiny droplets which will form an emulsion.
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Endemic
When a species evolves in isolation and is found in only one place in the world; it is said to be endemic (particular) to that area.
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Environmental isolation
This is when the climate changes in one area where an organism lives but not the others.
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Error - systematic
An error which is not determined by chance but is introduced by an inaccuracy in the system. Systematic errors are predictable and expected.
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Ethanol
Chemical found in alcoholic drinks and biofuels such as gasohol, its chemical formula is C2H5OH.
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Fair test
A fair test is one which only the independent variable has been allowed to affect the dependent variable.
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Other cards in this set

Card 2

Front

The chemical opposite of an alkali. when dissolved in water, its solution has a pH number less than 7. acids are proton H+ donors.

Back

Acid

Card 3

Front

The minimum energy needed to start off a reaction.

Back

Preview of the back of card 3

Card 4

Front

The site on an enzyme where the reactants bind.

Back

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Card 5

Front

The cells of algae, single-celled or simple multicellular organisms, which can photosynthesis but are not plants.

Back

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