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Meanings of the Terms/Words which are used in General Science Grade VI, VII and VIII
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Term/Word
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Meaning
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Glossary
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A list of terms in a special subject, field, or area of usage.
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Acid
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A compound containing hydrogen which dissolves in water to produce hydrogen ions (H+) in the solution.
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Acid rain
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Rain water which is more acidic than usual. Rain water normally has a pH between 5 & 6 but acid rains have pH below 5
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Acidic salts
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Salt obtained as a result of reaction between strong acid & weak base (Na2 CO3)
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Aerosol
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A pressurized container used to spray liquids, like paint, in a fine mist
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Alkali
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A base which dissolves in water is an alkali
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Alveolus
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An air sac found in the ling which is adapted for gaseous exchange
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Ammeter
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An instrument for measuring electric current
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Antibiotics
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Chemicals used to treat many infectious diseases caused by microorganisms such as bacteria
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Apparent brightness
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How bright a star looks to observes on earth
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A sexual reproduction
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Reproduction that doesn’t involve the fusion of two gametes
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Asteroids
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Large lumps of rock and metal that orbit the sun in a region called the asteroid belt between mars and Jupiter
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Astronomer
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A scientist who studies the stars, planets, and other objects in space
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Astronomy
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The scientific study of the objects in space such as stars, asteroids and planets
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Astrophysics
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The science of the physical and chemical aspects of heavenly bodies
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Atmosphere
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The blanket of gases that surrounds the earth
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Atmospheric pressure
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The pressure caused by the weight of the air pressing down on the earth’s surface
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Atom
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This is a basic of matter which can’t be further divided
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Basic salts
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Salt obtained as a result of reaction between strong base and weak acid (NaHCO3)
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Big bang
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A tremendous explosion on the beginning of the universe
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Big bang theory
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The idea that all the matter in the universe came into being with a massive explosion known as the big bang
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Biotechnology
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The use of biological process from microorganisms to make substances (e.g. penicillin) or to provide services for human beings
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Black hole
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What is left when a very massive star collapses at the end of its life. A black hole’s gravity is so strong that nothing can escape, not even light
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Breathing
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The process that brings about an exchange of gases between the organisms and the environment
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Bronchiole
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One of the many tiny tubes which carries air to end from the alveoli in the lungs
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Bronchitis
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A lung disease in which the cells lining the bronchi and bronchioles are inflamed
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Cancer
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A disease in which body’s cell start to divide and multiply in an uncontrolled and disorderly fashion
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Chemical Reaction
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A change in which one or more chemical elements or compounds(reactants) form new compounds(the products)
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Chemistry
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The scientific study of all substances and how they react and combine
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Chlorophyll
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A green pigment found in most plants. It absorbs light energy during photosynthesis
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Chromosome
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A thread-like structure present in the nucleus of a cell. It contains hereditary materials called genes
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Colloid
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A mixture of extremely small particles of a substance dispersed in another in which it doesn’t dissolve. The particles are smaller than in a suspension
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Comet
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An icy jump of material that moves around the sun in a highly elliptical orbit, its ‘tail’ is a thin stream of gas and dust that reflects sunlight
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Compound
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It consists of two or more elements chemically combined together
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Constellation
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Stars that appear to form a group with a definite pattern or arrangement, when viewed from the earth
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Current electricity
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The type of electricity that can flow through wires
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Decanting
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Process of separating a liquid from a solid that has settled by pouring the liquid carefully out of the container
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Deforestation
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Destruction of forests due to human activities
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Detergents
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Substances which when added to water, enable it to remove dirt
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Diaphragm
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A muscular from the abdomen,’ sheet that separates the chest
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Distillation
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The process of separating a mixture of liquids, or a liquid from an impurity, by heating. The vapor of the liquid with the lowest boiling point comes off first and is condensed back to a liquid in the condenser
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DNA
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(Deoxyribonucleic acid) Hereditary material of the cell
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Dwarf star
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A very small star that may be no larger than earth
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Dynamo
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A type of generator that produces direct current
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Eclipse
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The total or partial disappearance of a heavenly body when another one moves between it and the viewer
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Effector
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A muscle that respond to a message and reacts accordingly
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Electric charge
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Something that has an electric charge carries electricity. There are two types of electric charge, called positive and negative
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Electric circuit
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The path along which an electric current flows
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Electric current
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The flow of positive or negative electric charges
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Electric field
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The area in which an electric force has an effect
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Electric motor
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A device that changes electrical energy into movement
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Electric shock
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The effects on the human body caused by electric current from batteries
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Electricity
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The effect caused by the presence or movement of electrically charged particles
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Electrolysis
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Chemical reactions produced by passing electric current
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Electrolytes
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Electrolytes are chemical compounds, that help electric current to pass through them on ionization (e.g., Na CI, H2SO4)
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Element
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It is a pure substance which contains same type of elements
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Endothermic reaction
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A chemical reaction that takes heat from its surroundings
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Evaporation
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A change of state from liquid to gaseous (vapor), due to the escape of molecules from the surface. A liquid which readily evaporates is described as volatile
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Evening star
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Another name for the planet Venus, as it appears just after sunset
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Exothermic reaction
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A chemical reaction that releases heat into its surroundings
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Filtering
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The process of separating a liquid and a solid by pouring the mixture through a fine mesh (filter paper). The filter paper only lets liquid through PTO
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Galaxy
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A large group of stars, gas and dust
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Galvanometer
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An instrument for detecting or measuring very small electric currents
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Gamete
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A reproductive cell containing the haploid number of chromosomes
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Genes
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Units controlling inheritance and expression of characters
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Genetic engineering
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A technique used to transfer genes from one organism to another
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Genotype
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The genetic combination in an individual
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Generator
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A machine that turns the energy of movement, or kinetic energy into electrical energy
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Guard cells
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A pair of special cells present around opening (stomata) in the epidermis of a leaf that regulate the opening and closing of stomata
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Hereditary characters
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Characteristics which are inherited
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Heredity
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Transfer of characters from parents to their offspring
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Indicators
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A chemical compound that changes its color when an acid or an alkali is added into it
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Insulation
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A material that reduces heat transfer
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Irregular galaxy
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A galaxy with no definite shape or arrangement
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Kilogram (kg)
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Units of mass
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Lens
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A piece of transparent substance with curved surfaces, that makes light bend in a certain way
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Light-year
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The distance light travels in one year, or 9.5 trillion kilometers
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Luminous
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The term that describes any object that gives off light
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Mass
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The amount of matter that is in an object
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Mesophyll
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Cells found between upper and lower epidermis in a leaf. These cells contain chloroplasts
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Meter (or shooting star)
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A meteoroid that starts to burn up as it enters the atmosphere
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Meteorite
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Fragments of rocks striking the surface of the earth. The remains of a meteor that has survived the atmosphere and landed on earth
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Meteoroid
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A small piece of space debris
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Meteoroids
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Rocks or fragments of rocks and iron travelling in space
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Meter (m)
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Unit of length. 1000 meters equals 1 kilometer (km)
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Milky way
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A spiral galaxy to which out sun and the planets belong. The galaxy in which our solar system lies
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Milky way galaxy
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Such a galaxy containing solar system
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Mineral acid
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An acid which is produced chemically from a mineral e.g. hydrochloric acid is produced from sodium chloride and sulphuric acid is produced from sulpher
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Mixture
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It is formed by the combination of two substances in such a way that no new substance is formed
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Model
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A representation of something that can’t be seen easily or directly
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molecule
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It is formed by the combination of same or different atoms
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Motor neurons
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A nerve cell that transmits impulses to an effector
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Nebula
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Gigantic clouds of dust and gases in space
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Nerve
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A collection of nerve fibers
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Nerve fiber
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A long cytoplasmic extension of a cell body of a neuron. It serves to transmit impulses
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Neuron
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A nerve cell
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Neutron star
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A star whose core contains neutrons only
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Non-luminous
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Describes an object that doesn’t give out light of its own
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Optical microscope
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An instrument that uses lenses to make small objects look bigger
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Optical telescope
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An instrument that uses lenses and mirrors to make distant objects look closer
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Orbit
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The path in which one heavenly body moves around another
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Organic acid
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An organic compound that is acidic in nature. The most common ones are carboxylic acid (e.g., oxalic acid, formic acid, acetic acid)
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Palisade tissues
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Cylindrical cells arranged closely and vertically in the upper layer of mesophyll. These cells contain numerous chloroplasts which facilitate the absorption of sunlight
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pH
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Stands for power of hydrogen, a measure of hydrogen ion concentration in a solution
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Pneumatic
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Powered by the pressure of a gas, usually air
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Pressure
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A measure of the amount of force applied to a given area
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Receptor
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Sense organ, cell or nerve endings that detect stimulus
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Recycling
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Rendering used articles into useful ones
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Reflex action
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An immediate response to a specific stimulus without conscious control
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Respiration
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The process by which energy is released from food substances in living cells
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Revolution
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The movement of one object around another
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Rotation
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The spinning motion of an object
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Salt
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A compound formed by the neutralization reaction between acid & base
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Satellite
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Bodies that rotate in orbits around other bodies of greater mass under the influence of a gravitational field. For example, the moon is a natural satellite of the earth. Satellites which are used for relying radio, television and telephone signals around the earth are artificial earth satellites. They are called communication satellites.
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Second (s)
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Unit of time. A second is a duration in which the cesium -133 atom completes 9,192,631,770 vibrations under specified conditions
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Selective breeding
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Technology using breeding of selected organisms
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Sexual reproduction
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Reproduction that involves the fusion of two reproductive cells called gametes
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SI units
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An internationally agreed system of standard units used for scientific measurements
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Soap
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It is the sodium or potassium salt of a long-chain carboxylic acid. It is made by reacting animal fats or vegetable oils with Na OH or KOH. The process of making soap is called saponification
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Solar system
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The sun together with all of the planets and other objects orbiting it
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Solar wind
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A constant stream of invisible particles blow out into space from the sun
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Space probe
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Unmanned spacecraft sent to explore the solar system and beyond
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Space shuttle
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A reusable manned spacecraft that is launched like a rocket, but lands on reentry like plane
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Space station
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A large satellite orbiting the earth where astronauts can live and perform scientific research over fairly long period
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Stars
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Shinning objects of gases in nebula
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Sun
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This is a star
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Supergiant
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An extremely large star
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Suspension
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Fine particles of a solid suspended in a liquid in which the solid doesn’t dissolve
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True brightness
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The actual amount of energy in the form of light that is released by a star
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Universe (for cosmos)
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The collection of all matter, energy and space that exists
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Universe theory
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The idea that the universe expands and shrinks, in a repeating cycle of big bangs and big crunches
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Vacuum
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An empty space where there are no particles of air or other matter
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Variable resister (or rheostat)
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An electronic component that can be adjusted to give different amounts of resistance
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Variable star
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A star that changes gradually in brilliance
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Variation
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The differences that can be observed within a species
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Voluntary action
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An action that is controlled by the will
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Volume
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The amount of space something takes up. It is measured in cubic meters (m3). A smaller unit of volume is the cubic centimeter (cm3), o0 milliliter (ml). 1 cm3= 1 ml=1/1000000m3
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Weather forecast
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A prediction of what the weather will be for some time in the future
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Weight
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The measure of the force of gravity acting on an object
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X-Rays
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Wavelength, high-frequency electromagnetic waves that can pass through most soft substances but no hard, dense ones
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zygote
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A cell formed as a result of the fusion of the sperm and the ovum. It divides repeatedly and becomes the embryo
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