Primary General Science Glossary

This is a general primary science glossary. For class specific glossaries please go to the specific subjects


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Picture of Joseph Wainaina

Joseph Wainaina

Acid

Any water-soluble compound having a sour taste and capable of turning litmus red and reacting with a base to form a salt. Acid has a pH-level of less than 7.0 (A pH of 7 is neutral).

Acid rain

Rain which is unusually acidic (pH of less than the natural range of 5 to 6), caused mainly by atmospheric pollution with sulphur dioxide and nitrogen compounds.

Adaptation

Adaptation is the process by which living creatures (animals and plants) adapt or evolve to survive in their environment and to live amongst a specific group of other living things. 

Air

A mixture of gases (especially oxygen) required for breathing; the stuff that the atmosphere consists of.

Air pressure (Atmospheric pressure)

Air pressure is the weight of the atmosphere pressing down on the earth. It is measured by a barometer in units called millibars.

Air resistance

Air resistance is the force on an object moving through air. Air resistance affects how fast or slowly objects move through the air. 

Albert Einstein

Albert Einstein (14 March 1879 – 18 April 1955) was born in Germany and was a Jewish philosopher and author, who is widely regarded as one of the most influential and best known scientists and intellectuals of all time. In 1933, he joined the Institute for Advanced Study in Princeton, New Jersey and lived and worked there until his death. Einstein is probably familiar to most people for his mathematical equation about the nature of energy, E = MC2.

Alkaline

Relating to or containing an alkali, hence having a pH greater than 7. Alkaline batteries have potassium hydroxide as its electrolyte and a zinc / manganese dioxide cell.

Altitude

The height above sea level or above the earth’s surface.

Ambergris

A sperm whale secretion. Sperm whales produce it to protect their stomachs from the beaks of the cuttlefish they swallow, and formerly valued greatly in the manufacturing process of perfumes.

Ambient Temperature

The temperature of the surrounding air.

Amplifier

An electronic device that changes, usually increases, the strength or amplitude of a signal passing through it.

Amplifies

To make larger or more powerful; increase.

Amplify

To increase the volume of or ‘amplify’ sound.

Anemometer

An anemometer is a meteorological instrument that measures wind speed, either be gauging velocity or pressure.

Astrolabe

An ancient circular instrument used to observe and calculate the position of celestial bodies.

Atmosphere

The gases surrounding the Earth or any astronomical body of sufficient mass, held together by the gravity of the body.

Atoms

The smallest component of an element or ‘matter’ having the chemical properties of the element.

Bacteria

Very small living organisms made of only one cell which are present everywhere (the air, the soil, on the skin). Many types of bacteria can cause diseases, but others can be very helpful to humans.

Balance

A state of equilibrium

Balance point

The point along the length of the shaft at which it will balance itself when placed on a fulcrum.

Barometer

An instrument for measuring atmospheric pressure, used especially in weather forecasting, but is also used to measure altitude.

Barycentre

The point at the centre of a system; an average point, weighted according to mass or other attribute.

Base

The opposite of an acid. A Base has a pH-level of more than 7.0 up to 14.0 (A pH of 7 is neutral)

Battery

In an electrical circuit, the battery is the cell that makes electricity.

Benjamin Franklin

Benjamin Franklin, (January 17, 1706 – April 17, 1790) was one of the Founding Fathers of the United States of America. Franklin was a leading author and printer, satirist, political theorist, politician, scientist, inventor, civic activist, statesman, and diplomat. As a scientist, he was a major figure in the Enlightenment and the history of physics for his discoveries and theories regarding electricity.

Berlese funnel

A device in which soil is placed; heat and light are applied from above, forcing bugs into a container below it. Named after Antonio Berlese an Italian entomologist.

Bernoulli’s principle

The principle of conservation of energy applied to fluid flow: as the speed of a moving fluid increases, the air pressure within the fluid decreases. Named after Daniel Bernoulli, a Swiss mathematician and scientist, Bernoulli is famous for his work in the field of fluid dynamics. In 1738 he wrote a book called Hydrodynamica. In this book he explained his theories about how gases and fluids move, and how the speed at which they move affects the pressure they exert on objects they flow around.

Biceps

The biceps of a human is a muscle located on the upper arm. The biceps has several functions, the most important being to rotate the forearm and to flex the elbow.

Big dipper

A group of seven bright stars in the northern sky, near the pole – also called the constellation Ursa Major or the Great Bear.

Binary code

Electronic data used in computers. The circuit is either on or off and is represented with either a 1 or 0. The system uses the digits 0 and 1 to represent a letter, numeral or other character in a computer.

Binaural hearing

The perception of sound by stimulation of two ears affecting a listener’s ability to identify the location or origin of a detected sound in direction and distance.

Biosphere

A ‘biosphere’, also called an ‘ecospheres’, is a mostly closed ecosystem of a specific size that contains a mix of plants and animals that is completely self-sufficient.

Block and tackle

A block and tackle is a compound pulley where several pulleys are mounted on each axle, further increasing the mechanical advantage.

Buoyancy

The ability of water to support weight allowing an object to float.

Buzzer

An electrical mechanism that produces an intermittent current and an audible buzzing sound, or series of sounds, when electrical current flows through it.

Café Wall Illusion

This optical illusion was first observed and described by Doctor Richard Gregory when he noticed the curious effect in the tiles of the wall of a café in Bristol. This optical illusion makes the parallel straight horizontal lines appear to be bent. This illusion consists of alternating light and dark ‘bricks’ that are laid in staggered rows.

Calcium

A mineral salt that strengthens the bones.

Calcium carbonate

Calcium carbonate (CaCO3) is a common substance found in rock in all parts of the world, and is the main component of shells of marine organisms like snails, pearls, seashells and corals. Saltwater reef tank keepers have to dose or supplement this compound in order for corals to grow. Corals need calcium carbonate to grow.

Calligraphy

It is often called the ‘art of fancy lettering’ by means of an ink pen. This style of writing is described as a script and is often used for wedding invitations etc.

Camera obscura

A darkened enclosure in which images of outside objects are projected through a small aperture or lens onto a facing surface. A camera obscura uses the same principles as a regular camera.

Canines

Canines are teeth used for tearing and ripping food. Children learn about them as part of their study of teeth and how to take care of them.

Capacitor

A capacitor is an electrical component used to control the flow of charge in a circuit. The name derives from their capacity to store an electric charge. Capacitors consist of two conducting surfaces separated by an insulator; a wire lead is connected to each surface. A capacitor can store electric energy and discharge it at a determined rate.

Capillary action

The flow of liquids through porous media, such as the flow of water through blotting paper.

Caramel

Made by cooking sugar slowly, used in candy making and sweetening of foods

Carbon dioxide

Carbon dioxide is a colourless, odourless incombustible gas present in the atmosphere. It is formed during the breathing of living organisms, the decomposition and combustion of organic compounds, and in the reaction of acids with carbonates: used in fizzy drinks, fire extinguishers, and as dry ice for refrigeration.

Carcinogenic

A carcinogenic substance is any substance that produces cancer or stimulates the production of cancerous cells.

Carnivores

Carnivores are animals who eat mainly meat and hunt their prey. 

Cartesian diver

The Cartesian diver was first explained by René Descartes, a sixteenth-century French mathematician

Catalyst

A substance that initiates or accelerates a chemical reaction without itself being affected

Celestial bodies

Objects that are naturally occurring physical entities or structures, that current science has demonstrated to exist in outer space.

Cells

The basic structural and functional unit of all living organisms. Cells can exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants, animals or human beings.

Centre of mass

The point at which the entire mass of a body can be considered to be concentrated. Centre of mass / gravity The point at which the entire mass of a body can be considered to be concentrated.

Centrifugal force

Centrifugal force is the effect that tends to move an object away from the centre of a circle it is rotating about (a consequence of inertia).

Cereal

A breakfast food prepared from grain

Chemical element

Any of the more than 100 known substances that cannot be separated into simpler substances and that individually or in combination constitute all matter.

Chemical indicator

Any substance used to classify another, often by changing colour.

Chemical reaction

The formation of new substances from one or more reactants, by breaking existing electrical bonds and creating others.

Chlorophyll

A green-coloured compound or ‘pigment’ in plants that converts radiant energy to chemical energy through the process of photosynthesis.

Chromatography

An analytical chemistry technique for separating and identifying mixtures that are or can be coloured, especially pigments.

Circuit

A circuit is a closed loop for electricity to travel around. In primary school children learn about simple series circuits in which a single wire runs from a battery to a bulb and back again.

Circulatory system

The circulatory system is is the network of organs (including the heart) and vessels that allows the flow of blood, nutrients and oxygen around the body.

Climacteric fruit

The climacteric is a stage of fruit ripening associated with ethylene production and cell respiration rise. Apples, bananas, melons, apricots, tomatoes (among others) are climacteric fruit. Citrus, grapes, strawberries are non-climacteric (they ripen without ethylene and respiration bursts).

Cobalt chloride

A chemical substance often used to predict the presence of water molecules within the air or other substance.

Cocoon

The silky protective case spun by the larvae of some insects and moths in which they metamorphose.

Cohesion

Cohesion is a physical property of a substance, caused by the intermolecular attraction between like-molecules within a body or substance that acts to unite them.

Colour spectrum

The distribution of colours produced when light is dispersed by a prism. The order is displayed in the following order: Red, Orange, Yellow, Green, Blue and Violet.

Condensate

The opposite of ‘evaporate’. The transition from a gaseous state into a liquid state.

Condensation

Condensation is to turn from a gas into a liquid. In the water cycle, the evaporated water in the air cools and turns back into a liquid.

Conduction

The movement of heat through a material as kinetic energy is transferred from molecule to molecule. The handle of an iron pan on the stove gets hot due to heat conduction.

Conductor

A conductor is an object that allows electricity to flow through it easily. Objects made of metal are good conductors. 

Consumer

Within a food chain, a consumer consumes a producer (usually a plant) or another consumer by eating it. Consumers can be primary, secondary, tertiary, etc consumers depending on their position in the food chain. Consumers are also called predators of the animals they eat; animals eaten by other animals are prey.

Convection

The transfer of heat through a fluid (liquid or gas) caused by molecular motion. In the atmosphere, convection usually refers to the vertical movement of air masses. An example of convection is the rising of warm surface air and the sinking of cold air from upper levels of the atmosphere.

Convex / Concave

Curving or bulging outward or inward.

Creep

Creep is the tendency of a solid material such as soil, to slowly move or deform permanently under the influence of certain forces.

Current

Current is the amount of electricity flowing through a circuit. It is measured in amps.

Deciduous trees

Deciduous trees are those that shed their leaves in winter; their leaves are usually wide and flat.

Dehydration

Dryness resulting from the removal of water.

Density

The amount of matter contained by a given volume. The symbol of density is ρ (the Greek letter rho)

Desiccant

A substance that promotes drying.

Detergent

A detergent is a material intended to assist cleaning. The term is sometimes used to differentiate between soap and other surface-active chemical cleaning agents widely used in industry and laundering.

Dew point

The temperature at which the water vapour in the air becomes saturated and condensation begins. Dewpoint is expressed as a temperature in degrees Fahrenheit or Celsius.

Dextrin

Dextrin is obtained by hydrolysis of starch. It is a tasteless, odourless gummy substance that is often used as a thickening agent, in adhesives and in dietary supplements.

Diffusion

The process by which a substance moves from an area of high concentration, through a barrier or membrane, to an area of lower concentration.

Digestive system

The digestive system is made up of all the organs that help the body break down and process the food we eat.

Diopter

A unit of measurement of the refractive power of a lens, which is equal to the reciprocal of the focal length measured in meters.

Displacement

Displacement occurs when an object is immersed in a fluid, pushing it out of the way and taking its place.

Dissolving

Dissolving is a way of mixing a solid and a liquid. When a solid dissolves in a liquid it creates a solution.

DNA

Deoxyribonucleic acid is a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix. DNA is associated with the transmission of genetic information or all living organisms and some viruses.

Dominant eye

Also known as Ocular dominance is the tendency to prefer visual input from one eye to the other. It is somewhat similar to being right or left handed. The side of the dominant eye and the dominant hand do not always match.

Downforce

The downward pressure created by the aerodynamic characteristics of a car that allows it to travel faster through a corner by increasing the pressure between the contact area of the tire and the road surface, thus creating more grip.

Dye

A usually soluble substance for staining or colouring e.g. fabrics or hair.

Echo

The repetition of a sound resulting from reflection of the sound waves.

Echo-location

Determining the location of something by measuring the time it takes for an echo to return from it.

Echo-sounding

Determining the location of something by measuring the time it takes for an echo to return from it.

Eclipse

An eclipse is an astronomical event that occurs when one celestial object moves into the shadow of another.

Eddy-current

Circulating movement of electrical current within an electrical conductor caused by the intersection of the conductor with a moving magnetic field.

Elastic energy

Potential energy that is stored when a body is deformed as in a coiled spring or elastic band

Elastomer

Any polymer having the elastic properties of rubber.

Electric generator

A device that converts mechanical or kinetic energy to electrical energy. The reverse conversion of electrical energy into mechanical energy is done by a motor; motors and generators have many similarities.

Electric meter

A device that measures the amount of electrical energy consumed by a residence, business, or an electrically powered device.

Electrical current

Electrical current is the flow of charged electrons through a circuit. Electrical current, which is electrons flowing in a wire, can be explained as cars driving along a road, where the road is the wire and the cars are the electrons. The current would be the number of cars passing a given point.

Electricity

Electricity is a form of energy caused by electrons moving about.

Electrolysis

The process by which we generate hydrogen and oxygen from water is called electrolysis.

Electrolyte

An electrolyte is any liquid that is able to conduct electricity. Salt water makes an excellent conductor.

Electromagnet

An electromagnet is a type of magnet whose magnetic field is produced by the flow of electric current. The magnetic field disappears when the current ceases.

Electrons

Tiny particles with a negative charge that are capable of creating an electrical current.

Electroplating

The deposition of a metal coating onto an object by putting a negative charge on it and putting it into a solution which contains a metal salt. The metal salt contains positively charged metal ions which are attracted to the negatively charged object and are “reduced” to metallic form upon it.

Electroscope

A simple device that detects the presence of an electric charge by the mutual repulsion of metal foils.

Elodea

Elodea is a type of aquatic plant often called the waterweeds. Elodea is native to North America and is also widely used as aquarium vegetation.

Embryo

A minute rudimentary plant contained within a seed.

Emulsifier

A chemical that can bind two incompatible items, such as oil and water.

Endothermic reaction

A chemical reaction accompanied by the absorption of heat.

Entropy

The amount of order or disorder present in a thermodynamic system. Entropy measures how ordered the molecules of a substance are arranged and hence determines whether a material expands or contracts when heated.

Enzyme

Complex proteins produced by cells that facilitates or speeds up certain bio-chemical reactions in the body.

Equilateral triangle

In an equilateral triangle all sides have the same length and the same angles each measuring 60 degrees

Ethylene

Ethylene is an organic gas compound with the formula C2H4. This gas is produced by fruits and vegetables that is rotting and accelerates the ripening and aging process of nearby fruits.

Eutrophication

A process by which an excess of plant nutrients, for example nitrogen and phosphorous, reduces the oxygen dissolved within a body of water, producing an environment that does not readily support aquatic life.

Evaporate

The opposite of ‘condensate’. The transition from a liquid state into a gaseous state.

Evaporation

Evaporation is the process by which a liquid, when heated, changes into a gas and rises into the air. Evaporation is part of the water cycle as water from the earth’s seas and oceans evaporates when is heated by the sun’s rays. 

Evergreen trees

Evergreen trees (conifers) are those that keep their leaves all year around; they often have leaves shaped like needles.

Evolution

Evolution is the process of change to animal and plant species over long periods of time, or how plant species and animals have developed from generation to generation.

Exothermic reaction

A chemical reaction in which heat is given off during the formation of new chemical compounds.

Fair test

A fair test is a controlled investigation used to answer a question in a scientific way.

Fat

A soft greasy substance occurring in organic tissue and consisting of a mixture of lipids.

Ferrites

A magnetic material containing powdered iron oxide (Fe2O3) which usually has magnetic properties. Ferrous Of or relating to or containing iron. Metals that contain iron as the major alloying element.

Filament

A thin wire in a light bulb that is heated white hot by the passage of an electric current. Tungsten is often used.

Filtering

Filtering is a method of separating mixtures of solids and liquids.

Fingerprint

An impression of the underside of the end of a finger or thumb. It is used for identification because the arrangement of ridges in any fingerprint is thought to be unique and permanent with each person.

Fire extinguisher

Any of various portable steel container devices for spraying and extinguishing a fire with Carbon dioxide or other chemicals.

Float

To be afloat either on or below a liquid surface and not sink to the bottom of the liquid.

Fluid

A fluid is a substance that continually deforms or ‘flows’. All gases and most liquids are considered to be fluids. The main characteristic of a fluid is that they are capable of flowing and easily changing shape.

Food chain

A food chain is a diagram that shows us how animals are linked by what they eat.

Food web

A food web is a set of linked food chains.

Force

Forces are the pushes and pulls which act on our bodies and the things around us to make things move and stop moving.

Freezing

Freezing is the process of changing a liquid into a solid.

Freezing point

The temperature at which a liquid changes state and forms a solid.

Friction

Friction is a 'sticking' force – the resistance that a surface or object encounters when moving over another surface or object. Air resistance, water resistance and surface resistance are kinds of friction.

Fulcrum

The pivot about which a lever turns

Fungus

An organism of the kingdom ‘Fungi’ lacking chlorophyll and feeding on organic matter.

Fuse

Also called a ‘fusible link’ is a type of over current protection device. It consists of a metal wire or strip that melts when too much current flows, which interrupts the circuit in which it is connected.

Galileo

Galileo Galilei was an Italian astronomer and mathematician who was the first to use a telescope to study the stars; demonstrated that different weights descend at the same rate; perfected the refracting telescope that enabled him to make many discoveries (1564-1642).

Galvanometer

A type of ammeter or instrument for detecting or comparing or measuring small electric currents.

Gas

Gas is one of the three states of matter on Earth. A gas can flow, expand and be squeezed.

Gear

A toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion.

Genetically engineered plants

The alteration of the genome of plants grown for food in order to produce crops with specific advantages.

Germination

Germination is the process of a seed starting to grow to create a new plant.

Golden section

A mathematical or geometrical proportion where the ratio between a small section and a larger section is equal to the ratio between the larger section and both sections put together.

Grafting

A method of plant breeding widely used in agriculture and horticulture, where the tissues of one plant are encouraged to fuse with those of another.

Gravity

Gravity is the pulling force acting between the Earth and a falling object. Gravity pulls objects to the ground. 

Grounding

The process of connecting equipment to a common ground or ‘earth’. This is done as a safety mechanism in order to avoid the unsafe energizing of equipment.

Gyroscopic effect

Having the effect of a gyroscope – a rotating mechanism mounted so that its axis can turn freely in one or more directions. A spinning gyroscope tends to resist change in the direction of its axis.

Habitat

A habitat is a home environment for plants and animals or other organisms. 

Heat

A form of energy that is transferred by a difference in temperature.

Helium

Helium is the chemical element with atomic number 2 and an atomic weight of 4.0026, which is represented by the symbol He. Helium is a colourless, odourless and tasteless gas. It also makes up a small amount of the air we breathe. It originates from the Greek word ‘helios’ meaning the sun. Helium is commonly used as a cooling agent in superconductors, cryogenics, inflating balloons as well as inflating airships.

Herbivores

Hernivores are animals whose diet mostly consists of plants.

Hering Illusion

This is an optical illusion named by Ewald Hering. The vertical or horizontal lines are all straight, but look as if they were bent. The distortion is produced by a lined pattern on the background that simulates a perspective design and creates a false impression of depth.

Hermann Grid Illusion

This is an optical illusion named by ‘Ludimar Hermann’ in the 1800’s. The illusion is characterised by blobs perceived at the intersections of a light-coloured grid between black squares.

Hormone

A chemical substance produced in a living organism which controls the rate of biochemical processes.

Horticulture

The science of caring for gardens or gardening; small scale agriculture.

Hot-air balloon

Balloon for travel through the air in a basket suspended below a large bag or ‘envelope’ of heated air.

Humidity

The relative humidity is a measure of the amount of water vapour in the air (at a specific temperature) compared to the maximum amount of water vapour air could hold at that temperature, and is given as a percentage value.

Hydroelectric power

Hydroelectric power is electricity generated by hydropower, i.e., the production of electrical power through the use of the gravitational force of falling or flowing water.

Hydrogen peroxide

An almost colourless, slightly pale blue liquid. H2O2 is soluble in water. Hydrogen peroxide is used as a mild antiseptic and is often found in bleaching agents, especially for bleaching hair.

Hydroponics

A technique of growing plants (without soil) in water containing dissolved nutrients.

Hygrometer

Measuring instrument for measuring the relative humidity of the atmosphere.

Hyphae

Small threads that are part of a fungus. These thin strands stretch out to gather food and nutrients to allow the fungus to grow.

Ice

Water frozen in the solid state.

Igneous rock

Igneous rock is one of the three kinds of rock present on Earth. It is formed when magma or lava from volcanoes cools; basalt and granite are both igneous rocks.

Igneous rocks

Rocks that is produced under conditions involving intense heat.

Immiscible

The chemical property where two or more liquids or phases do not readily mix or dissolve in one another, such as oil and water.

Immiscible liquids

Immiscibility is two or more liquids that are not mutually soluble or un-mixable, whereas miscibility is the property of liquids to mix in all proportions, forming a homogeneous solution.

In Parallel

Connected at the same time. Electrical components connected side by side, instead of in series.

In series

Electrical components connected in a chain, instead of in parallel.

Incisors

Incisors are teeth used for biting and cutting food. Children learn about them as part of their study of teeth and how to take care of them.

Inclinometer

A measuring instrument for measuring the angle of magnetic dip. Airplane pilots make use of this device to show the angle that an aircraft makes with the horizon.

Indicator

Any substance used to classify another, often by changing colour.

Induction

An electrical phenomenon whereby an electrical current is generated in a closed circuit, by a stroking a magnet along a conductor.

Inertia

The tendency of a body to maintain its state of rest or uniform motion unless acted upon by an external force.

Infra-red rays

Invisible radiation in the part of the electromagnetic spectrum characterized by wavelengths just longer than those of ordinary visible red light and shorter than those of microwaves or radio waves.

Insulator

An insulator is an object that does not allow electricity to flow through it easily. Rubber, paper and some plastics are good insulators.

Integrated circuit

A collection of active and passive electrical components such as transistors and resistors mounted on a single slice of silicon and packaged as a single component. An integrated circuit is also known as an IC, microcircuit, or microchip.

Invertebrates

Animals who don't have a bony skeleton are called invertebrates; insects, spiders and crabs are invertebrates.

Invisible ink

A substance used for writing, which is invisible either on application or soon thereafter, and which can later on be made visible by some means.

Iodine

A non-metallic element belonging to the halogens. Iodine is used especially in medicine and photography and in dyes. It occurs naturally only in combination in small quantities as in sea water or rocks.

Iris

A muscular diaphragm that controls the size of the pupil which in turn controls the amount of light that enters the eye. The iris forms the coloured portion of the eye.

Iron

A metallic chemical element with the symbol ‘Fe’ and atomic number 26.

Irreversible change

An irreversible change is a change that cannot be changed back again. Burning or mixing a liquid with bicarbonate of soda are examples of irreversible changes. 

Isaac Newton

Sir Isaac Newton (1642-1727), a mathematician and physicist were of the foremost scientific intellects of all time and who is famous for his ‘action-reaction law’ which states: ‘to every action there is an equal and opposite reaction’.

Jean Foucault

Jean Bernard Léon Foucault (18 September 1819 – 11 February 1868) was a French physicist best known for the invention of the Foucault pendulum, a device demonstrating the effect of the Earth’s rotation.

Kaleidoscope

A tubular instrument containing loose bits of coloured glass, plastic, etc. reflected by mirrors so that various symmetrical patterns appear when the tube is held to the eye and is rotated

Kazoo

A toy wind instrument that has a membrane that makes a sound when you hum into the mouthpiece.

Kelvin

Kelvin is the fundamental unit of temperature adopted under the Systeme International d’Unites (SI).  It is not calibrated in terms of the freezing and boiling points of water, but in terms of energy itself.  The number 0 K is assigned to the lowest possible temperature, called ‘absolute zero’.

Kilowatt hour

A kilowatt-hour (kWh) is a standard metric unit of measurement for electricity consumption for billing purposes. It can simply be described as 1000 watts of electricity used for one hour.

Kinetic energy

The energy possessed by an object by virtue of its motion is called kinetic energy.  The greater the mass or speed of the object, the greater is the kinetic energy.  Kinetic means active or moving.  Kinetic energy can be defined as energy in motion or the energy of a moving object.

Knee-jerk reaction

The involuntary contraction of the leg when the knee is tapped with a doctor’s mallet.

Landslide

A rapid down slope mass movement where water in the soil and rock has accumulated to sufficiently increase stress and lubricate bedding planes.

LED

A type of a semi-conductor or ‘solid state’ light source. LED’s can produce a very bright light for a small amount of power. LED’s are now used in many applications, for example car brake lights and traffic lights, although white coloured LEDs are still a relatively new technology.

Leonardo da Vinci

Leonardo da Vinci, born in 1452, is considered as perhaps the most diversely talented person ever to have lived. Primarily known as an artist for his paintings and sculpting, he was also a scientist, mathematician, engineer, inventor, musician, writer and architect and was recognized in many more fields! It is even rumoured that he could paint with one hand and write with the other at the same time. Although relatively few of his designs were constructed or were even feasible during his lifetime, Leonardo is praised for his technological ingenuity. He conceptualised a helicopter, a tank, concentrated solar power, a calculator and many, many more during his lifetime!

Lever

A rigid bar used to apply pressure at one point along its length by applying a force (effort) at a second point and turning about a third point or fulcrum.

Life cycle

A life cycle is the different stages of life for a living thing.

Lift

A fluid flowing past the surface of a body exerts a surface force on it. Lift is defined to be the component of this force that is perpendicular to the oncoming flow direction. Lift Take off or away by decreasing the air pressure.

Light

Light is the energy that allows us to see the world. A light source makes light by using another kind of energy (for example heat or nuclear energy).

Lignum

Wooden tissue. This may or may not contain the bark of the tree as well.

Liquid

Liquid is one of thre three states of matter on Earth. A liquid forms a poo, flows or runs but it can't be stretched or squeezed.

Litmus

A colouring material (obtained from lichens, a composite organism consisting of fungi) that turns red in acid solutions and blue in alkaline solutions. It is used as a very rough acid-base indicator.

Little dipper

A cluster of seven stars in the constellation Ursa Minor also called Little Bear. At the end of the dipper’s handle is ‘Polaris’, the North Star.

Logic gate

A computer circuit with several inputs but only one output that can be activated by particular combinations of inputs

Lumens

The SI unit of luminous flux. It is a measure of the power of light that can be perceived by the human eye.

Lunar month

The average time between successive new or full moons. A lunar month is equal to 29 days 12 hours 44 minutes. Also called a ‘synodic’ month.

Lye

Lye is a strong alkaline substance, commonly ‘sodium hydroxide’ or ‘caustic soda’ (NaOH).

Machine

Any mechanical or electrical device that transmits or modifies energy to perform or assist in the performance of human tasks. Also, a device that has parts to perform or assist in performing any type of work.

Magnet

A magnet is an object that has a magnetic field (an invisible pattern of magnetism). A magnet attracts or repels other items.

Magnetic field

A condition in the space around a magnet or electric current in which there is a detectable magnetic force and two magnetic poles are present.

Magnetic force

Magnetic force is an invisible force created by electrons. Magnetic force controls magnetism and electricity.

Magnetic North

North according to the Earth’s magnetic poles rather than its geographic poles. Declination from true north is given in miles where one mile equals 1/6,400 of 360 degrees.

Magnetism

Magnetism is a force caused by the electrons in the atoms that make up everything around us.

Magnification

A measurable increase in the apparent size of an object. This enlargement is quantified by a calculated number also called ‘magnification’. Magnification is the ratio between the apparent size and the true size of the viewed object behind the lens or other magnifier.

Male ants

Male ants do not work and live only a few weeks or months. The only purpose of the male ant is to mate with the queens and they die shortly thereafter.

Maltose

A white crystalline sugar formed during the digestion of starches.

Mantle

Earth’s mantle is a rocky shell about 2,890 km thick that constitutes about 84 percent of Earth’s volume. It is predominantly solid and encloses the iron-rich hot core, which occupies about 15 percent of Earth’s volume.

Material

Materials are the matter or substance that objects are made from. Examples of materials are metal, plastic, wood, glass, ceramics, synthetic fibres and composites. Different materials have different features, or properties, which make them suitable for different uses.

Matter

Matter makes up our planet and the whole universe. On Earth, all matter exists in one of three different states: solid, liquid or gas.

Mealworms

Mealworms are the larva form of the mealworm beetle, ‘Tenebrio molitor’, a species of darkling beetle. Like all holo-metabolic insects, they go through four life-stages: egg, larva, pupa, and adult. Mealworms are a tasty treat for hamsters.

Melting

Melting is the process of changing a solid into a liquid.

Membrane

A pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants.

Meniscus

The curved top of a column of liquid, such as ‘water’ in a small tube. It is formed because the attractive forces between the tube and the water molecules (adhesive forces) are stronger than the cohesive forces between individual water molecules.

Metabolism

The chemical reactions that allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually synonymous with energy production.

Metals

Any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets. Most metals also have magnetic properties.

Metamorphic rock

Metamorphic rocks like slate or marble are formed when other kinds of rock (igneous or sedimentary) are changed due to heat or pressure.

Methylene blue

A blue dye used as a stain, an antiseptic, or a chemical indicator. Methylene blue has many uses in a range of different fields, such as biology and chemistry.

Michael Faraday

Michael Faraday was a British physicist and chemist, best known for his discoveries of electromagnetic induction and of the laws of electrolysis. Born in 1791, Faraday was the son of a blacksmith and received little formal education. While working for a bookbinder in London, he read many scientific books and experimented with electricity. Faraday’s most important scientific contributions were in the fields of electricity and magnetism. In 1821 Faraday plotted the magnetic field around a conductor carrying an electric current, and in 1831 he followed this accomplishment with the discovery of electromagnetic induction.

Micro-habitat

A micro-habitat is is a very specific, small home environment (like a tree or a pond) for plants, animals and insects.

Microbes

Minute living organisms, including but not limited to bacteria, viruses and fungi.

Milliammeter

A sensitive ammeter for detecting small currents, graduated in milliamperes.

Molars

Molars (and pre-molars) are teeth used for grinding and crushing food. Children learn about them as part of their study of teeth and how to take care of them.

Mold

A fungus that produces a superficial growth on various kinds of damp or decaying organic matter.

Momentum

Momentum is the product of the mass and velocity (speed) of an object (p = mv).

Moon

A moon is a celestial object that orbits a planet. 

Mordant

Any substance used to facilitate the fixing of a dye to a fibre

Morse Code

A telegraph code in which letters and numbers are represented by strings of dots and dashes (short and long signals).

Motion picture

Series of images on a strip of film usually projected at the rate of 24 frames per second, which make up a conceptually complete work. Also referred to as a film.

Mummification

The preserving of a dead body, by making it into a mummy.

Mycology

The branch of living sciences concerned with the study of fungi.

Natron

Natron is a natural salt, composed of sodium carbonate and sodium bicarbonate with traces of sodium chloride and sodium sulphate. It was used by the ancient Egyptians to dry out the bodies during mummification.

Nocturnal

Animals or insects that is active during the night and sleep during the day.

Non-ferrous metals

Non-ferrous metals are those that have very little iron content. Non-ferrous metals are non-magnetic metals such as gold, silver or aluminium.

Ohm’s law

Ohm’s law states that the current through a conductor between two points is directly proportional to the potential difference or voltage across the two points, and in reverse proportional to the resistance between them.

Oil

Any of a group of fats that is a liquid at room temperature that are obtained from plants.

Omnivores

Ominivores are animals who eat a mixture of plants and meat.

Opaque

Things are opaque if light cannot pass through them.

Optic nerve

The optic nerve transmits visual information from the retina to the brain.

Optical illusion

An optical phenomenon that results in a false or deceptive visual impression.

Optician

A specialist in fitting eyeglasses and making lenses to correct vision.

Oscillator

A tuned electronic circuit used to generate a continuous output repetitive variation, typically in time.

Oscilloscope

An electronic device with a screen, which displays a picture of the voltage of an electrical signal. When this device is connected to the output of an audio amplifier, it displays patterns related to the sound pressure coming out of the loudspeaker.

Osmosis

Osmosis is the diffusion of a liquid through a cell wall or membrane. Osmosis is the means by which water and nutrients move.

Oxidation

The addition of oxygen to a compound accompanied with a loss of electrons

Photosynthesis

Photosynthesis is the process plants use to make food from sunlight; it also requires carbon dioxide (from the air), and water (from the soil).

Pitch

Pitch is the quality of a sound. Depending on how fast or slowly something vibrates a sound's pitch with be high or low.

Planet

A planet is a celestial object that orbits a star like our solar system's Sun.

Pole

A magnet's north pole is the end of the magnet attracted to the Earth's North magnetic pole; a magnet's south pole is the end of the magnet attracted to the Earth's South magnetic pole. 

Precipitation

Precipitation is rain, sleet, hail and snow, the water droplets which fall from the sky. 

Producer

Within a food chain, a producer (usually a green plant) passes energy on to a consumer (an animal who eats the plant) through carbohydrates and proteins.

Reflection

Reflection is when light hits the surface of an object and then that light travels to our eyes so we can see. Mirrors catch light rays in front of them and throw it back in the direction it came from.

Reversible change

A reversible change is a change that can be changed back again. Melting and heating are examples of reversible changes.

Season

The four seasons (autumn, winter, spring, summer) we experience on our planet are caused by the Earth's tilt as it rotates around the Sun.

Sedimentary rock

Sedimentary rocks like sandstone or chalk are formed over millions of years when sediments (tiny pieces of rocks and organic matter) are pressed together. 

Senses

Children learn about the body's five senses (hearing, sight, smell, touch and taste) as part of primary science.

Shadow

A shadow is the darkness formed when light rays cannot pass through something.

Sieving

Sieving is a method of separating mixtures of solids and liquids.

Simple machines

Simple machines work by turning small forces into larger ones, allowing us to perform tasks with more strength or speed. Examples of simple machines are levers, gears, pulleys, wheels and screws.

Solid

Solid is one of the three states of matter on Earth. A solid can hold its shape.

Sound

Sound is created when something vibrates and sends waves of energy (vibration) into our ears. 

States of matter

Matter makes up our planet and the whole universe. On Earth, all matter exists in one of three different states: solid, liquid or gas. Depending on its temperature, matter can change state; heating, cooling, evaporating and condensation are ways in which a material changes state.

Sun

A sun is a star, a giant ball of hot gas. Our Sun makes life possible on Earth.

Surface resistance

Surface resistance is the force on objects moving across a surface.

Switch

A switch turns an electrical circuit on or off by starting or stopping a current flowing.

Transparent

Things are transparent if most light can pass through them.

Vertebrates

Vertebrates are animals with backbones / skeletons and include amphibians, birds, fish, mammals and reptiles.

Voltage

Voltage is the amount of electrical energy used. It is measured in volts. 

Water cycle

The water cycle is the continuous journey water takes from the sea, to the sky, to the land and back to the sea.

Water resistance

Water resistance is the force on objects floating on or moving in water. 

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