We are constantly exposed to claims in the media that assert to be scientific, such as:
- “Our product is scientifically proven to work,”
- “Our product is better because it’s free of chemicals,”
- “This is only a theory, so we can consider alternative ideas.”
People generally trust scientific authority, but don’t necessarily understand how science actually works. Unless you understand how science works, how can you know whether or not to trust “scientific” claims?
At a first glance, we can consider statements like the ones above and ask the following questions:
- What does “scientifically proven” mean?
- Free of what chemicals? All matter, including our bodies, is made of chemicals.
- What is a theory and how easily can we disregard it? Gravity is also a theory, and everyone accepts that it works!
A scientist, with an understanding of the scientific method, would ask more analytical, probing questions:
- How was the product shown to work? What experiments were done and were they valid, accurate and reliable?
- What chemicals is it free of? Were those chemicals tested for safety? There must still be chemicals present, are those known to be safe?
- In everyday language, “theory” means hypothesis. In science, a theory is a hypothesis that has been supported by experiment. So what evidence supports a theory? How easily can I disregard this theory and consider alternatives? What evidence supports the alternatives?
Why is Science Important to Students?
An understanding of scientific method is important in our modern technological society and, for this reason, scientific skills are examined every year in the HSC in all science subjects. The assessment is in the form of practical tests, where you design and perform an experiment, and collect, analyse and present data. Often you draw graphs and calculate various quantities, and draw conclusions. You are also asked to examine experimental designs, and consider why and how an experiment is valid, reliable and accurate, and how it can be improved.
Applying scientific skills and understanding the scientific method are areas where many students struggle, since these ideas rarely get taught explicitly in schools. By Year 12 these skills are assumed knowledge in Biology, Chemistry, and Physics.
Students are often told, “you can’t study for a skills test, because it tests skills, not knowledge.” This is false. You can certainly learn the skills required for understanding how to perform and talk about experiments, how to collect and analyse data, and how to critically assess results.
As a bonus, understanding the scientific method will make it more difficult for people to trick you!
What is the Scientific Method?
The scientific method works as follows:
- You start with an observation (a fact),
- You develop a testable hypothesis. The hypothesis is a rule that explains your observation. The hypothesis needs to be testable is so that people can check if it’s correct.
- The hypotheses also need to make predictions, so the predictions can be tested.
- You test the hypotheses and their predictions by doing experiments and collecting more facts.
- If the hypotheses and predictions hold up to all valid experiments, it becomes a theory.
The experiments we use to test hypotheses and theories need to be valid, accurate and reliable. These three words have specific meanings in this context:
- An invalid experiment is one that is fundamentally flawed, and is incapable of correctly testing the theory. For example, using the wrong equipment or making the wrong assumptions makes an experiment invalid.
- The accuracy of an experiment is related to how single measurements are made, e.g. using a stopwatch to time something is more accurate than counting “one Mississippi, two Mississippi,…”.
- Reliability means getting the same result every time; how repeatable a result is. If you get a different result every time, then how do you know which result is correct?
According to the scientific method, if your theory makes a prediction, and your valid, accurate and reliable experiment gives a result that matches that prediction, then you can assume that your theory is correct in this particular instance. You can continue with this assumption until an experiment gives a different result to what your theory predicted. If an experiment gives a different result, then you have to investigate why: does your theory need revising, or was your experiment flawed?
If you want to learn more about validity, accuracy, and reliability, you should read our detailed blog post .
Why is Science Important to Society?
The scientific method and science, in general, are often misunderstood as a way to accumulate facts. However, there is a big difference between facts and understanding. You do need the facts that are generated by science, but you also need to use these to gain an understanding of the physical world around us. This understanding is used to improve our lives through the development of technology. All modern technology, like the device you’re reading this blog on, and the internet that allows you access this blog, are only made possible by the understanding achieved through science.