Revise
The Scientific Method
The Scientific Method Revision
The Scientific Method
The scientific method is how scientists work. It makes sure that ideas are tested thoroughly so that scientists can develop reliable theories and models. If new evidence is found, these theories may be changed or replaced.
Hypotheses
An observation is a measurement or a process that a scientist does not understand.
A hypothesis is a proposed explanation for the observation.
Hypotheses are not immediately accepted. They must undergo thorough testing by lots of scientists before the scientific community agrees if the hypothesis is likely to be correct. Even then, scientists know that new evidence may be collected in the future that disproves their hypothesis.
For example, if biologist observes that a species of plant grows better in farmland than woodland, they may hypothesise that the plant grows better in bright sunlight and this is why they grow better in farmland. More data would need to be collected to find out if this hypothesis is true or if whether another factor is causing the observations.
Evidence
Scientists first collect their own evidence. This evidence may support or oppose their hypothesis. They then publish their findings in peer-reviewed journals or at conferences.
Other scientists then peer-review the first scientist’s experiments to check that their experiments were accurate and their conclusions are sensible. They then perform their own experiments to check the first scientists results and collect more evidence. If this evidence does not fit with the original hypothesis, it may need to be changed or replaced entirely.
In the example from the previous revision box, other biologists will collect data from other locations to see if the plant species grows well in sunny areas and less well in shaded areas. They will also compare other factors that may affect the growth of the plant such as water sources, nutrients in the soil and natural predators. They may also perform laboratory experiments to see how different light intensities affect the growth of the plant species. The results of all of these experiments are evidence.
Theories and Models
Accepted hypotheses are called theories. These hypotheses have been tested many times and are yet to be disproven.
However, theories are not necessarily fact. They are the best explanation that scientists currently have. In the future, new evidence may be found that shows these theories are incorrect and they will have to be changed or replaced.
Models are simplified descriptions based on theories. They are used to explain observations and make predictions. It is important to remember that models may not be completely accurate – they have limitations. For example, the Bohr Model is a useful way of representing the atom in chemistry and physics. However, we know that it is not an accurate picture of the way that electrons behave.
The Scientific Method Example Questions
Question 1: What is a hypothesis?
[1 mark]
A proposed explanation for an observation.
Question 2: Why might a hypothesis have to be replaced?
[1 mark]
New evidence is collected that disproves the hypothesis.
Question 3: What is a theory?
[1 mark]
A scientifically accepted hypothesis.
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