People can have opinions about these issues and science may be able to provide information about them but science on its own cannot provide the answers.
Activity Which of the following questions do you think are suitable for scientific investigation?
1. Who was the best poet of the twentieth century? 2. Why do rainbows only appear when it rains? 3. Is it right to clone animals? 4. Is it possible for humans to travel to Mars? 5. Should humans travel to Mars? 6. Why do we never see aliens when they come to earth? 7. Who is the best singer in Ireland? 8. How strong is human hair?
3.3 Posing a hypothesis
When carrying out scientific investigations scientists usually form an initial idea to explain their observations. This initial idea is known as a hypothesis. The hypothesis must be able to provide a logical explanation for the observations and must be testable in some way. A hypothesis can only develop into a theory if it is testable. A hypothesis is tested by making further observations and seeing if they match the observations that would be expected. Scientific testing is usually based on two questions: 1. If the hypothesis is correct, what would we expect to see? 2. Does what we actually observe match this?
Hypotheses are supported when actual observations (i.e. results) match the expected observations. Hypotheses are contradicted when they do not match.
Example If we see a rainbow and observe that it is raining and that the sun is shining, we may form the hypothesis that sunshine and rain together form rainbows. Based on this hypothesis we would expect to see a rainbow the next time that the sun is shining while it is raining. If we then observe rain and sunshine together and a rainbow appears, then the hypothesis is supported. If we observe rain and sunshine together but no rainbow appears, then the hypothesis is not supported.
When the results do not support the hypothesis, further investigation is necessary. For example we might choose to investigate if the position of the sun is a factor in the appearance of rainbows. This would be a new hypothesis to test.
