Knowing and Thinking Level 2


The Scientific Process and the metalanguage of science

The scientific method attempts to develop new insights and understandings or to integrate or correct previously held ideas. There is a range of terms that are used in science to describe the investigative process. In level 1 you were briefly introduced to the metalanguage of science. This section treats it more extensively.

The intentions of the scientific experiment or investigation are expressed as an ‘aim’. The aim of an investigation is underpinned by an hypothesis. Scientists propose hypotheses as explanations of phenomena. An hypothesis is a proposed general explanation based on some understanding of the phenomenon being investigated. For example, when investigating the absorbency of paper towels two alternative hypotheses might be:

  1. the thicker paper towel will be the most absorbent

  2. the more expensive paper towel will be the most absorbent.

From the hypotheses predictions are made and experiments are designed to test the predictions. A prediction in this instance could be:

  1. ‘Thicko’ has the thickest sheets of paper towel, so it will be most absorbent

  2. ‘Cheapo’ is the cheapest brand so it will be the least absorbent.

Predicting scientifically — A distinction needs to be made about the difference between the scientific understanding of the term prediction and that used in everyday language. In the everyday sense prediction is a guess about what might occur. Astrology provides examples of non-scientific predictions. While predictions are often based on our past experiences, scientific predictions are based on understanding and logic related to cause and effect relationships. A scientific prediction follows an hypothesis which is a proposed explanation that is developed to describe an observation so as to relate two variables.

For example, an hypothesis could be that the harder you exercise, the faster your heart beats. This hypothesis is in the ‘If.... then....’ format. A well-worded prediction will suggest an investigation that is based on a fair test. The first part of an ‘If.... then....’ statement relates to the independent variable and the second part to the dependent variable. In the example, the heart rate depends on the exercise and not vice versa.

Scientific investigations need to be valid in their design. This means that one variable is deliberately changed, one variable is measured or observed to determine the results and that other variables are controlled. Any difference in results can be attributed to the variable that is deliberately changed. We often teach this idea through the mnemonic ‘Cows Moo Softly’. (Change one thing, Measure something, Keep everything else the Same).

Scientific investigations need to be repeated or replicated to ensure the results are reliable. We sometimes call an investigation that is both valid and reliable a ‘fair test’.

Conclusions are drawn on the basis of evidence. The evidence is often the result of a scientific investigation.

The results of science investigations lead to the development of scientific models, theories and laws.