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The development of scientific theories

A scientific theory is a general explanation that applies to a wide range of situations and examples.

• As technology develops more data can be collected and new types of observations made.
• A hypothesis is a testable explanation of an observed event. New data that contradicts a hypothesis may lead to a new scientific explanation. The hypothesis is changed. A good example of this is the atomic model.
• Sometimes scientists come up with different explanations for the same data.
• When new data is produced, an accepted scientific explanation or theory is not usually immediately overturned. The existing explanation survives until a better explanation is produced.

Examples of scientific theories are the Big Bang theory for the creation of the universe and the theory of evolution in biology.

Peer review

Scientists across the world form a scientific community. In school, your peer group are other students of your age. For scientists, their peers are other scientists, usually in the same area of research.

Scientific claims from new research that is published in journals must be peer reviewed, that is evaluated by other scientists who are experts in that area of science.

Scientists check that the research is:

1. Valid - Does it measure what it says it does, was the method designed correctly and appropriately?
2. Original - Has anyone else already carried out similar research, and has their work been credited? Are the results new?
3. Significant - Are the findings of the research important?

Evaluating scientific claims

Claims that are from research that is not peer reviewed should always be questioned. There could be problems with the method used, the accuracy of results or the conclusions drawn.

Research should also be questioned if it is based on data that is not:

• repeatable by the scientists who carried it out, or
• reproducible by teams of scientists elsewhere