The Scientific Method
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What is the Scientific Method?
Turning ideas and thoughts into scientific knowledge involves a process called investigating.
Scientists have a typical way of investigating, called the SCIENTIFIC METHOD.
This starts with careful OBSERVATIONS. All of the five senses: sight, hearing, smell, taste and touch, are used to collect information.
The scientist then forms a HYPOTHESIS. This is a carefully thought-out idea about why something has occurred. Scientists do this by INFERENCE - deciding what they think the information means.
The hypothesis is tested out by EXPERIMENTS to see if it remains true in new situations.
If the hypothesis always correctly predicts what will happen, it may become an accepted scientific THEORY. Theories are always changeable, if new facts show that they do not always work.
In a scientific investigation you:
Follow a set scientific method
Observe and measure what happens
Collect, record and process information
Interpret results to reach a conclusion
Learn how and why something happens
Show trends, patterns, relationships and scientific laws.
Observations, Inferences and Predictions
An observation is something that you can see or find out using your senses. For example, you can observe that a pile of decomposing rubbish smells, that tūi sing at sunrise or that a green apple tastes sour.
Observations are important in Science as they are often a starting point for further questions and provide information in investigations.
Once you have made an observation you often try to explain it. Such an explanation is called an inference.
Look at the photo of the 'face' on the surface of the planet Mars. This photo is the record of observations made using powerful telescopes, cameras and computers. Perhaps the 'face' was carved by an ancient Martian civilisation. Or maybe it was formed naturally by erosion of the Martian surface. These are two possible inferences to explain the 'face', and one of them is almost certainly wrong.
Inferring is an important skill in science, and you need to remember three things about it.
You can usually make several different inferences from the same observation. For example, in Fig 14(a) the boy has made an observation: The dog is barking. He has also made an inference: He must have found a rabbit. The girl has made another possible inference: or a hedgehog.
Observations are correct, provided the observer has been careful and honest in reporting the observations. On the other hand, inferences often turn out to be incorrect. Inferences can be tested by further observations, as in Fig 14(b).
It is therefore important not to confuse observations and inferences. Otherwise you may think something is 'fact' when it is only an 'educated guess'
Another important skill is predicting. This is making a forecast of what a future observation may be. Predictions are based on your observations and what you already know. For exam-ple, if you have been observing the moon each night you can confidently predict whether there will be a full moon tonight. Otherwise you can only guess, and probably be wrong.
What are the first steps in an investigation?
Investigations start with an Aim or a purpose. An Aim is needed so you know what you are working towards finding out by carrying out the investigation.
An Aim is written as a sentence that often start with “To find out...”
For example: To find out if the age of a hen affects the size of the egg they lay.
To find out if temperature affects the biological sex of turtle eggs.
To find out if eating oats lowers cholesterol in a humans blood.
Investigations then need a Hypothesis, which is an educated guess as to what you think the answer to the investigation will be, before you carry it out. The whole point of an experiment is to test the Hypothesis - to determine if the Hypothesis is correct, or not.
Hypothesises are written as sentences that start with a prediction “I think that...” For example : I think that older hens will lay smaller eggs than younger hens.
I think that warmer turtle nest temperatures will make more female turtles.
I think that eating at least 1/2 cup of oats will reduce cholesterol levels in men.