To begin a scientific investigation you must ask a clear question that can be tested. For example, why do icebergs float?
This question will draw on scientific knowledge that already exists.
In science, each new discovery builds on the discoveries that have gone before. In the words of Isaac Newton, ‘If I have seen further than others, it is by standing upon the shoulders of giants.’
You should find out as much information as possible about the problem you want to solve.
z Hypothesis
Once research has been done and a question has been asked, a scientist will make an educated guess about what the answer might be. This is called a hypothesis.
A hypothesis is an idea that will be tested by an investigation.
For example, the question ‘Why do icebergs float?’ will become the hypothesis ‘Icebergs float due to a lower density than liquid water’.
A hypothesis must be testable. For example, a hypothesis that can be tested is ‘A dog pants in order to cool down’. An example of a hypothesis that cannot be tested is ‘Putting your left sock on before your right sock will give you luck’.
A hypothesis cannot be tested if the technology needed does not yet exist. For example, at present it is impossible to test the hypothesis ‘Life exists in other solar systems’.
Hypothesis or not?
In pairs, consider which of the following statements are hypotheses that could be tested in a scientific investigation:
zz zz z z zz zz
Diesel cars cause more air pollution than petrol cars. Orange is the nicest colour.
A diet rich in sugary foods leads to high blood pressure. A die thrown with your left hand is more likely to turn up a six. The colour of the sky is blue.
Consider how you would develop investigations to test each of the reasonable hypotheses. 2 Fig. 0.1.3
Science can test and attempt to explain natural phenomena such as ‘Why do icebergs float?’
