Key Terms

Define ...

A definition is a sentence that has the structure shown in the table below:

Sugar is a substance that is sweet and gives us energy.
Albert Einstein was a famous scientist who discovered the Theory of Relativity.
Dinosaurs were animals that lived on earth millions of years ago and are now extinct.

List ...

A list is a series of words. Usually they have a similar concept or theme.

Examples are:

  • List the common names of six insects. - ant, bee, fly, mosquito, cockroach, grasshopper
  • List the planets in order from the sun. - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto

State ...

To state something is to repeat a rule, a law or a learned fact exactly as you learnt it.

Examples are:

  • State the rule for speed. - Speed = Distance / Time
  • State the scientific name for humans. - Homo sapiens
  • State the Law of Conservation of Energy. - Energy cannot be created nor destroyed in any chemical reaction. It can only be changed from one form to another.

Describe ...

To describe an object or a living thing in science is to write relevant scientific terms that relate to the appearance or behaviour of the object or living thing as in the examples below:

  • Describe the metal called iron. - Iron is a metal that is shiny, silver in colour, hard, strong, magnetic, conducts heat and electricity, has a high melting point, has a high boiling point, and corrodes or 'rusts' in air.
  • Describe an insect. - An insect has an external skeleton or 'shell', has 3 body parts, has 3 pairs of jointed legs, has 1 pair of antennae, and has a changing body temperature.

Explain why / Account for / Give reasons for ...

An explanation is a sentence or a paragraph with clear and detailed reasons why something happens.

Examples are:

  • Explain why popcorn 'pops'. - Popcorn 'pops' because the small amount of water contained in the original corn kernel expands over 300 times when it changes from water liquid to water gas (steam) as the corn kernel is heated. This force makes the corn kernel rapidly break apart.
  • Give a reason why paint 'dries'. - The reason why liquid paint dries is because the solvent (e.g. turpentine) evaporates leaving behind the dried coloured layer of paint.

Infer / Draw a Conclusion ...

To 'infer' or 'draw a conclusion' means to explain why something happened or what will happen next.

Examples are:

  • Carbon dioxide is found in only the solid ('dry ice') and the gaseous states. What conclusion can be drawn from this? - Not all substances change from solid to liquid to gas when heated, and gas to liquid to solid when cooled. Carbon dioxide is an exception in that it does not have a liquid form.
  • Horses and donkeys both have similar characteristics such as fur, teeth type, and head and body shape. Using your knowledge of evolution, infer why this could be so. - Horse and donkeys possibly evolved from a common ancestor that had the same characteristics as both the horse and the donkey.

Compare and Contrast ...

'Compare' means to write the similarities and differences between 2 things.

'Contrast' means to highlight the differences between 2 things.

Examples are:

  • Compare and contrast the horse and the cow. - The main similarities between a horse and a cow are that they are both mammals and herbivores. The main differences between a horse and a cow are that the horse has faster movement and is not used for meat or milk production, whereas the cow has slower movement and provides meat and milk for humans to consume.
  • Compare and contrast the radio and the microwave oven. - The main similarity between a radio and a microwave oven is that they are both electrical appliances, but the main differences between the radio and the microwave oven is that the radio receives radio waves to make sound and the microwave oven makes microwaves for heating food.

Discuss ...

  • A discussion is an argumentative paragraph or short essay that contains at least one sentence / paragraph stating the reasons for or the advantages of a particular item or idea, and at least one sentence / paragraph stating the reasons against or disadvantages of the item or idea. The paragraph / essay may also contain a sentence in conclusion stating an opinion based on factual evidence.
  • An example is: Discuss the advantages and disadvantages of Australia's use of solar energy. - The advantages of using solar energy are that it is renewable, abundant and non-polluting. The disadvantages of using solar energy are that it is only suited to areas where there is little cloud cover, is expensive to set up and is not very efficient. Australia should use solar energy to a greater extent in the future as we have almost constant sunshine and have the research and development skills to improve the efficiency of solar devices.