Botswana JCE Science (Syllabus 14) key terms

A testable statement that suggests a possible explanation for an observation, which can be checked by collecting evidence in an experiment.

Any factor in an experiment that can change or be changed, such as temperature, time, or amount of substance used.

An investigation in which only the factor being studied is changed while all other conditions are kept the same, so results can be trusted.

A standard set-up in an experiment where the factor under test is absent, used for comparison with the experimental set-up.

Information gathered using the senses or measuring instruments, describing what actually happens rather than what is expected.

A conclusion drawn from observations and prior knowledge, explaining what the observations probably mean.

A judgement about whether the results support the hypothesis, based on the evidence collected during an investigation.

A number obtained by comparing a quantity with a known unit using an instrument, usually written with its unit.

An internationally agreed standard unit of measurement, such as the metre for length, kilogram for mass, and second for time.

The equipment and instruments set out and used to carry out a practical investigation or scientific procedure.

Anything that has mass and occupies space, existing as a solid, liquid, or gas in everyday conditions.

A very small piece of matter, such as an atom or molecule, whose arrangement and movement explain the properties of substances.

The physical form of a substance, usually solid, liquid, or gas, determined by how its particles are arranged and move.

The change of state from solid to liquid when a substance gains heat energy and its particles move faster and break free.

The change of state from liquid to solid when a substance loses heat energy and its particles become fixed in position.

The change of a liquid into a gas at its surface, happening at any temperature as faster particles escape.

The change of a gas into a liquid when it is cooled and its particles lose energy and come closer together.

The spreading of particles from a region of high concentration to low concentration because of their random movement.

The amount of a dissolved substance present in a given volume of solution, often described as dilute or concentrated.

A mixture formed when a solute dissolves in a solvent, appearing uniform throughout, for example salt dissolved in water.

The substance that dissolves in a liquid to form a solution, such as sugar in water.

The liquid in which a substance dissolves to form a solution, for example water in salt water.

Two or more substances combined without chemical bonding, which can usually be separated by physical methods.

A pure substance formed when two or more elements combine chemically in fixed proportions, with properties different from the elements.

A pure substance made of only one kind of atom that cannot be split into simpler substances by chemical means.

The smallest particle of an element that can take part in a chemical change, made of a nucleus and electrons.

A separation method that passes a mixture through a filter to trap solid particles while the liquid passes through.

The smallest living unit of an organism, containing cytoplasm and genetic material and able to carry out life processes.

A group of similar cells working together to perform a particular function in a living organism.

A structure made of different tissues working together to carry out a specific job, such as the heart or leaf.

A group of organs that work together to perform a major function in the body, such as the digestive system.

The process by which green plants use light energy, carbon dioxide, and water to make glucose and release oxygen.

The chemical process in living cells that releases energy from glucose, using oxygen and producing carbon dioxide and water.

The green pigment in plant cells that absorbs light energy needed for photosynthesis to take place.

A sequence showing how energy passes from one organism to another through feeding, beginning with a producer.

An organism, usually a green plant, that makes its own food by photosynthesis and so starts a food chain.

An organism that cannot make its own food and obtains energy by eating other organisms in a food chain.

A push or pull acting on an object that can change its shape, speed, or direction of movement, measured in newtons.

A force that opposes motion when two surfaces move or try to move against each other, producing heat.

The force of attraction between objects with mass, which pulls objects towards the Earth and gives them weight.

The amount of matter in an object, measured in kilograms and unchanged by the object's position.

The force of gravity acting on an object's mass, measured in newtons and changing with the strength of gravity.

The ability to do work or cause change, existing in forms such as kinetic, potential, light, heat, and chemical energy.

The energy an object has because of its movement, increasing with greater mass and greater speed.

Stored energy that an object has because of its position or condition, for example a raised object or stretched spring.

A material that allows heat or electricity to pass through it easily, usually because it contains free electrons.

A material that does not allow heat or electricity to pass through it easily, used to protect and contain energy flow.

A complete closed path through which electric current can flow, containing a source, wires, and a component such as a lamp.

The Sun together with the planets, moons, asteroids, and other objects that orbit it under the influence of gravity.

A large spherical body that orbits a star, such as Earth, and does not produce its own light.

The curved path followed by one object around another in space because of gravitational attraction.

The spinning of an object about its own axis, which for the Earth causes day and night.

The movement of one object around another along a path, such as the Earth travelling around the Sun each year.

An imaginary line through the centre of an object about which it turns, such as the tilted axis of the Earth.

A period of the year with characteristic weather, caused by the tilt of the Earth's axis as it revolves around the Sun.

The continuous movement of water between the Earth's surface and the atmosphere through evaporation, condensation, and precipitation.

The condition of the atmosphere at a particular place and time, described by temperature, rainfall, wind, and cloud cover.

The average pattern of weather in a region over many years, including typical temperatures and rainfall.

The wearing away and removal of the top layer of soil by wind or flowing water, often worsened when vegetation is cleared.