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DAY The time it takes a planet to revolve once on it axis. One Earth day = 24 hours

DECOMPOSE When a compound is split apart into two (or more) simpler substances, usually by heating. more

eg if blue (hydrated) copper sulphate is heated it will decompose into anhydrous copper sulphate (a white powder) and water.

DECOMPOSER An animal that lives on the rotting remains of other organisms. Decomposers help in the recycling of dead material returning essential nutrients to the ground.
eg fungi, bacteria, various beetles, worms

DENSITY Mass per unit volume.  more

This means the mass (in grams) of one cubic centimetre of a substance OR the mass (in kilograms) of one cubic metre of a substance.
The unit of density is grams per cubic centimetre (g/cm3).

Density is calculated as Density = mass / volume

eg a block of iron with a volume of 3cm3 has a mass of 27g . This tells us the density of iron = 27÷ 3, = 9g/cm3.

This means that the mass of one cubic centimetre of iron is 9 grams.

The density of water is 1 g/cm3. Anything with a density more than that of water will sink and anything with a density less than water will float.
A substance with a LOW density will take up more space (volume) than a substance with a high density.

DIAPHRAGM A sheet of muscle across the body, above the abdomen but below the lungs, that enables us to breath.

DIFFUSION  
The gradual mixing of two substances due to the fact that they are made of tiny particles that are continuously moving. Diffusion happens quickly between two gases but a lot more slowly between two liquids. Examples of diffusion : i) The smell of some perfume will diffuse across the room.

ii) The purple colour produced by a dissolving potassium permanganate crystal will slowly diffuse into some water.

iii) A balloon will slowly deflate because the particles will diffuse through the rubber.

A balloon filled with hydrogen will deflate quicker than one filled with carbon dioxide because hydrogen particles are smaller, lighter and travel faster.

DIODE An electrical component that only allows a current to flow in one direction.

DISTILLATION The name of the process used for obtaining the SOLVENT from a SOLUTION

eg obtaining pure water from sea water.

Fractional distillation is the process for separating two (or more) liquids from each other. It relies on the liquids having different boiling points. eg i. obtaining alcohol from beer ii. obtaining petrol from crude oil. The gases in air can be separated by the fractional distillation of liquid air.

DISTILLATE The liquid that has been distilled.

EAR Used for HEARING. Rapid changes in air pressure cause the eardrum to vibrate. The ear also controls BALANCE by making use of small tubes filled with liquid and lined with tiny hairs.

ECLIPSE Eclipse of the moon: when the Earth's shadow falls onto the moon, so that the moon cannot be seen. Eclipse of the sun: When the Earth blocks out some of the Sun's light so that it cannot all be seen.

ECOLOGY The study of animals and plants in their natural environment.

ECOSYSTEM A community of animals and plants and the habitat where they live.

EGESTION When unused food and other solid waste is got rid of from the body.
NOT to be confused with excretion which is the term used to describe the removal of waste products formed  by chemical reactions within the body.

EGG DUCT See FALLOPIAN TUBE.

ELEMENT A chemical substance in its simplest possible form. There are about 107 different elements. Elements consist of only a single kind of atom and cannot be decomposed. Examples of different elements: Iron, copper, oxygen, sulphur.

EMBRYO The young child inside the uterus. While the child is only partly formed it is often called a FOETUS (fetus).

ENDOSKELETON An internal hard skeleton (as found in vertebrates).

ENERGY Something has energy if it can be used to do any useful job of work. The unit of energy is the joule. Different types of energy include:

Nuclear energy, electrical energy, heat energy, sound energy, light energy, kinetic (speed) energy, potential (height) energy, chemical energy and strain energy.

Example of objects which contain energy:
    Coal has chemical energy
    A spinning flywheel has kinetic energy
    A stretched elastic band has strain energy
    A brick on a shelf has potential energy

Law of conservation of energy:     

    Energy can never be created or destroyed, only changed from one form to another

Examples of energy conversion:
A falling ball converts potential energy to kinetic energy.
A petrol engine converts chemical energy to kinetic, sound and heat energy.
Whenever anything slows down then kinetic energy is converted into heat energy.

RENEWABLE energy is energy that can be replaced and usually starts from the SUN eg wind power, solar energy, hydroelectric energy, wave power. Renewable energy is usually cleaner and causes less pollution. NON-RENEWABLE energy cannot be replaced eg coal, oil and natural gas (these are also called FOSSIL FUELS.

ENVIRONMENT The conditions which effect the life and development of animals and plants within the habitat. Examples of physical factors which effect the environment are air temperature, soil pH, and air humidity.

EVAPORATION The process for obtaining the solute from a solution by warming the solution and letting the solvent evaporate completely away. eg obtaining SALT from SALTY WATER.

EXOSKELETON An external skeleton (as found in insects).

EYE Used for seeing. Contains a LENS which focuses light onto light sensitive cells found in the RETINA.

FACTOR Something that effects the outcome of an experiment.
Example 1. The factors that effect how fast a block of wood might slide down a slope might be i) the size of the block of wood, ii) the weight of the bloack and iii) the steepness of the slope
Example 2. The factors that effect how quickly a cup of water cools down might be: i)the size of the cup, ii) the temperature of the water and iii) what the cup is made out of.

FALLOPIAN TUBE Sometimes called an EGG DUCT. Carries the eggs from the ovary to the uterus. Where an egg is fertilized. The eggs take about seven days to travel down the Fallopian tube.

FERMENTATION The process where yeast converts sugar into alcohol and carbon dioxide. It is a process used in the brewing industry (where the sugars in wine or beer is changes to alcohol) and in baking where the carbon dioxide makes the bread rise.

FERTILIZATION The fusion (joining) of the male and female gamete.

FILAMENT  
i Male part of a flower. Supports the ANTHER
ii    The thin metal coil if wire in a light bulb that gets hot when a current flows through it and glows. It is usually made of tungsten which has a very high melting point.

FILTER (n) A piece of transparent, coloured plastic that absorbs some colours and not others.

FILTER (v) The process of separating a solid from a liquid by passing it through a piece of filter paper.

FILTRATE The clear liquid that drips through the filter paper when filtering.

FILTRATION The process used for separating a SOLID from a LIQUID eg obtaining SAND from SALTY WATER.

FISH One of the VERTEBRATES. A animal that lays soft jelly covered eggs in water. Have scaly skin. eg trout.

FLATWORMS Segmented worms, mostly parasitic eg tapeworm.

FLOWER The part of a plant that contains the reproductive organs. Where the plant makes seeds. Flowers that are insect pollinated (eg rose) have colourful or scented petals to attract insects. Wind pollinated plants (eg grass) do not have petals but still have flowers.

FLOWERING PLANTS Plants that produce SEEDS. Eg grass, apple, oak, rose.

FOETUS (fetus) The name given to a partly developed baby (embryo) before it is born

FOOD CHAIN A list of organisms to show a simple feeding pattern within a habitat

eg cabbage leaf ˙ slug ˙ thrush ˙fox

A food chain always starts with a plant:

Plant ˙ herbivore ˙ carnivore

The arrows show the transfer of food energy from one organism to the next.

FOOD WEB A diagram that represents several interlinked food chains

FORCE A Push or a pull. Measured in NEWTONS (n). A force can cause an object to speed up, slow down or change shape. Examples of forces: friction, gravity, magnetism, electrostatic charge. Forces usually work in pairs.

An object will speed up or slow down if the forces on it are not balanced.

If an object is stationary (or moving at a steady speed) then the forces on it must cancel themselves out (we say that the forces are in equilibrium).

This block will only speed up if the pulling force is greater than the force of friction

FREQUENCY The rate at which something occurs eg in SOUND it means the number of sound vibrations that occur every second. Measured in hertz (Hz). Middle C on the piano is 440Hz, which means 440 vibrations every second.

FRICTION A force which causes a moving object to slow down. Friction always acts in the OPPOSITE direction to the direction of motion. Sometimes friction is an ADVANTAGE eg slowing down a man with a parachute or the brakes of a car slowing it down; and sometimes it is a disadvantage eg air resistance slowing down a car and using more petrol, or bearings heating up.

Friction always tries to convert KINETIC ENERGY into HEAT ENERGY.

Without friction we would not be able to walk along and cars would not be able to accelerate or turn corners.

FULCRUM The point on which a lever rests or is supported.

The further a force is from the fulcrum, the more effect it has on the load. see lever.

FUNGI A group of plants that do not possess green chlorophyll so cannot carry out photosynthesis.

They take their food from the material they are growing on/in. They reproduce by forming spores.
Examples of different fungi: mushroom, yeast, mould.
Fungi (along with bacteria) are very important in the food chain for the recycling of nutrients in the soil.
Some fungi are harmful and can cause disease in crops (eg potato blight).
Some fungi are useful to man eg yeast which is used to ferment sugar and produce alcohol in the brewing industry.

GALAXY A large number of stars grouped together. Our sun is in a galaxy called the Milky Way. The universe contains many galaxies.

GAMETE Sex cell. One of the cells that fuse during sexual reproduction. Contains only half the number of chromosomes in the nucleus compared to a normal cell. 
MALE GAMETE: in plants = pollen, in animals = sperm
FEMALE GAMETE: in plants = ovule, in animals = ovum.

GAS In gases the particles are far apart and free to move rapidly in straight lines about but are continuously bumping in to one another ( or the edge of the container) and changing direction. A gas always fills up whatever container it is placed in.

GESTATION PERIOD The time taken for the embryo to form in the uterus (ie the time from fertilization to birth) In a human this is 9 months.

GUT See ALIMENTARY CANAL

HABITAT The place where an animal or plant makes its home
eg woodland, fresh-water stream, puddle.

HEART Muscular organ to pump blood around the body. Contains valves to control the direction of blood flow.

HERBIVORE (Herbivorous) An animal that eats only plants. (leaves, seeds, berries, bark etc) eg snail, mouse

HOOKE'S LAW Hooke’s law states that the extension of a spring will be proportional to the load hanging on it.

ie if the load is doubled then the extension will also double. NOTE: do note muddle up the extension of a spring with it's length.

HORMONE Chemicals in the body that control certain functions such as the rate of a boy/girls growth. Hormones are made in several parts of the body. The hormones responsible for the changes at puberty are made in the testes or ovaries.

HOST The organism on which a parasite is living
eg if a flea lives on a fox then the fox is the host and the flea the parasite.

HYDROCARBON A compound containing only the elements HYDROGEN and CARBON. eg petrol, wax
Hydrocarbons will burn to form the compounds carbon dioxide and water.

INSECTS Animals that have 3 pairs of legs, 3 parts to the body and usually 2 pairs of wings eg butterfly, ant. The eggs from an insect hatch into larvae. The larva is the young form of an insect. A caterpillar is the larva of a butterfly. A maggot is the larva of a fly.

Useful insects include the bee which helps pollinate flowers and also provides us with honey. A lot of insects are decomposers (eg fly and many beetlles) and play an important part in the ecosystem recycling dead plants and animals.

Insects can carry disease (eg mosquito carries malaria). Insects can harm food crops which either get eaten or damaged by insects.

INSOLUBLE Cannot be dissolved. eg sand is insoluble in water; sugar is insoluble in petrol NOTE: when using the words soluble or insoluble then you should give the name of the solvent being used.

INVERTEBRATES Animals without a backbone. All animals except for mammals, birds, reptiles, amphibians and fish are invertebrates.

KIDNEY i) Removes waste (urea) from the blood. ii) Removes water from the blood and so controls the blood concentration.The liquid which the kidneys remove is called URINE which passes down the URETER to the bladder.

LARGE INTESTINE The last stage in the GUT. An organ in our body where water absorption takes place.

LDR Light Dependant Resistor. This is a resistor which has has a high resistance in the dark and a low resistance in the light.

LEAVES Where photosynthesis is carried out in a plant. Have a large surface area to absorb the sunlight.

LED Light Emitting Diode. A small device that gives out light but only uses a tiny current. It allows a current to only flow in one direction.

LEVER A device for increasing the effect of a force. The load needs to placed near to the fulcrum and the effort (or applied force) further from the fulcrum.

LEVER LAW Sometimes called the law of MOMENTS. When a lever is balanced then this law applies:


Force on the left x its distance from the fulcrum = force on right x its distance from the fulcrum

ie on left.... 4n x 9cm = 36 on the right... 6n x 6cm = 36

LIEBIG CONDENSER A special glass tube used to cool down and condense a hot gas. Water flows through an outer glass jacket and this keeps the inner glass tube cool.

LIQUID In liquids the particles are still close together but only held together by WEAK electrical forces which leaves them free to slide over one another. A liquid has a fixed volume but takes up the shape of its container.

LIME Sometimes called quicklime. See calcium oxide. It is alkaline and is used in agriculture to neutralise an acid soil.

LIVER The largest organ in the body. It helps keep a balance of nutrients in the body and can also help remove poisons from the body. This is why the liver is often damaged when a person drinks too much alcohol (a poison) or takes drugs.

LUMINOUS Gives out light eg the sun, a light bulb or candle.

LUNGS Organ in the body that is responsible for gaseous exchange ie
i) Transfers oxygen to the blood.
ii) Removes carbon dioxide from the blood.

MAMMALS One of the VERTEBRATES. The young are born alive. The females have mammary glands and suckle their young from nipples on mammary glands. Have hair or fur on their bodies eg mouse, man. Warm blooded.

MASS The mass of an object is a property of the object which NEVER changes. It is a measure of an objects resistance to a change in motion. Mass is measured in kilograms (or grams)

MENISCUS The curved surface found on the surface of a liquid. NOTE: Any readings taken of the volume of water in a container should be taken to the LOWER side of the meniscus. (diagram)

METAL An element that has most of the following properties:Malleable, ductile, shiny, good conductor of heat and electricity. Metal oxides, if they dissolve, form ALKALINE solutions. Eg copper, iron, tin, gold.

MINERAL A naturally occurring substance from the ground, usually crystalline. eg Malachite

MIXTURE At least two substances present that can be separated without a chemical reaction taking place. No new substance is formed when a mixture is separated.
Examples of mixtures: AIR, SEA WATER, INK.

MOLECULE The particle formed when two or more atoms chemically join together.

MOLLUSCS Animals that have muscular foot and soft body eg slug, snail, oyster.

MOSS A small plant. It has no proper roots. It reproduces spores. Live in damp, shady places.

NECTARY Part of a flower that contains nectar to attract insects. Helps with POLLINATION

NEUTRAL a liquid with a pH value equal to pH 7. Example: water, ethanol

NON-FLOWERING PLANTS Plants that do NOT produce seeds. Eg algae, moss and fungi.

NON-METAL An element that has most of the following properties:
Brittle, poor conductor of heat and electricity. Non-metal oxides, if they dissolve, form ACIDIC solutions. Note: CARBON, even though it conducts electricity, forms an ACIDIC oxide and is therefore classed as a non-metal.

NUCLEUS Controls the function and behaviour of the cell. Found in ALL living cells. Contains the GENETIC MATERIAL.

OMNIVORE An animal that eats plants and meat. (Omnivorous)
eg rat, human

ORE A mineral from the ground from which a metal can be obtained.

OVARY  (plant)  The part of a flower where the seeds are formed,. Contains the OVULES. After fertilization the ovary will often form a FRUIT.

OVARY (animal) Where eggs/ova (female gamete) are manufactured.

OVULES The part of a flower that contains the FEMALE GAMETE. The ovules will swell and become seeds after fertilization.