Aim & Hypothesis

In the scientific method, the AIM is a statement that describes the purpose or objective of an investigation. It clearly states what you are trying to find out or achieve through the investigation.

The Aim should: 

• Be easy to understand and avoid unnecessary words.

• Be specific and focused.

• Not make a prediction about the outcome (because thats a hypothesis!)

For example, 

• Instead of: "To find out if plants grow taller in sunlight." (This is a hypothesis)

• A better aim would be: "To investigate the effect of sunlight on plant growth."

Before starting an experiment, scientists write a HYPOTHESIS. A hypothesis is an educated guess (based on evidence and prior knowledge to answer the question behind the experiment (the research question).

Observation investigations are a starting point, leading to futher investigations. A new hypothesis is made, based on observational evidence and inferences from these initial observations. This new hypothesis then leads to follow up experiments. 

A true or valid experiment will test only one hypothesis at a time. If you get this far and realise your question cannot be answered by investigating, you will need to go back and look at whether any part of your question involves something that cannot be measured. If so, rephrase your question so it can be measured.

Another way to write a hypothesis is to make an inference and then convert that inference to a hypothesis. For example, many parts of New Zealand have a dry season. Grass changes from being green to being brown or yellow. One observation is that the grass does not turn brown as quickly near the edges of a concrete path but remains green for much longer.

We can make an inference, based on our experience and deduced from the facts. An inference is like an educated guess and is a possible answer. A valid inference is one that explains all the observations.

Some inferences that may explain why grass growing near the edge of the concrete path remains green in summer are as follows.

1. This grass receives the rain runoff from the path when it rains.

2. The concrete path insulates the grass roots from the heat and cold.

3. People do not walk on this part of the grass.

4. The soil under the path remains moist while the soil under the open grass dries out.

5. More earthworms live under the path than under the open grass.

For Inference 2 above, the hypothesis might be:

If the temperature of the grass roots were measured, then the grass roots under the path would be cooler than the grass roots beside the path.