Is Earth spherical, or is it really flat? This discussion has been going on for years, and there are many explanations and arguments supporting both sides. Then, how can we know the truth? Now more than ever, with the spreading of technology, we can have much information within our reach. However, we cannot simply take every claim we encounter as valid! The internet is an excellent example of this. Anyone can publish and share statements and claims that have no basis but still spread like wildfire. So, how can we know what information to trust?
We can use the scientific method to decide which results and explanations can be accepted to be scientifically correct. The scientific method is a set of steps scientists take when exploring their research topics and answering questions they have about them, validating statements and claims, and, ultimately, confirming truth. In this article, we will explore these steps and learn how we can design good experiments to put our ideas to the test and find a good explanation for a specific phenomenon.
Scientific Method Physics definition
Earlier, we briefly described what the scientific method is. Let us discuss it in a bit more detail and have a look at its definition.
The scientific method is an ordered series of steps to acquire knowledge based on experimental evidence.
The knowledge acquired using this method is always backed up and tested using carefully designed experiments. Because of this, we say that this method is based on empirical evidence.
When we use this method, the goal is to add to scientific knowledge, confirm or disprove elements of a scientific theory or a scientific theory as a whole, or settle any answers or doubts.
All the steps that comprise the scientific method are important. We should not skip steps as it could result in incorrect results or conclusions.
Scientific Method Steps
The steps of the scientific method are:
- Ask a question about something you observe
- Do background research to learn what is already known about the topic
- Construct a hypothesis
- Experiment to test your hypothesis
- Analyze the data from the experiment
- Draw conclusions.
The research process starts when scientists observe a phenomenon and make questions about it. Formulating questions is vital. Good questions can guide scientists through their research.
After a question is formulated, scientists must then do background research on the topic. Appropriate research needs to consult relevant sources such as books and scientific articles that have been already validated by other experts in the area or even scientific institutions. Once scientists are done with research, they can formulate a hypothesis.
A hypothesis is an assumption we make to explain our observations that is capable of being proven to be wrong by an experiment.
The type of hypothesis that the scientific method requires needs to be able to be proven false by experimentation, and it is known as a falsifiable hypothesis. It does not mean that it is wrong, but rather that if it is wrong, we can find out by observing a carefully designed experiment. Hypotheses that are inherently impossible to be proven false, either because of technical limitations or subjectivity, are known as non-falsifiable hypotheses.
"Dreams are heavier than thoughts" is a non-falsifiable hypothesis. There is no way to weigh a dream or a thought so it is not only impossible to know which is heavier. On the other hand the hypothesis "all oranges are heavier than apples" is falsifiable. It is enough to find an apple that weighs more than an orange to prove it wrong!
Experiments must be carefully designed in order to trust the data we receive and therefore analyse it properly. This analysis is what allows us to draw proper conclusions from the data, knowing if our hypothesis is correct or not. After this is done, we are able to report our results to the scientific community.
Fig. 1: Scientific method steps.
Scientific Method Experiments
We know that scientists conduct experiments to check their hypotheses. But how do they come up with these experiments?
In an experiment, measurements must be done, either directly or indirectly, to obtain the data for further calculations. Thinking of a way to measure a quantity in a precise way is part of designing our experiment.
Fig. 2 - Scientists must design experiments carefully to obtain precise results
Therefore, experiments have to be designed carefully. Another important thing to consider is how to control our experiments. This means that we need to design our experiment in such a way that we keep our experiment conditions isolated from the effect of variables that could hinder our measurements, leading to wrong interpretations of our results. You need to be able to change the variable you are testing and leave the others unchanged.
Imagine that you are trying to research how to increase sleep quality. You formulate a hypothesis that "sleeping in a dark room improves sleep quality" and you plan to prove by qualifying how rested you feel after sleeping for a couple of days with lights on and some with lights off. However, after those two days, you sleep with the lights off, but you also exercise before bedtime and you find that you slept much better. This experiment is not controlled. You cannot know if sleep quality improved because of having the lights off, the exercise, or both!
In order for an experiment to be valid, it must be reproducible under the same conditions. This means that other scientists can replicate it and get the same results. Getting drastically different results in two experiments with the same conditions means that there was a mistake in one of the versions, and thus we can not trust the results.
An incorrect experiment can lead to erroneous results and conclusions, where false data is mistakenly backed up.
A good example of what can go wrong in an improperly designed experiment was when a group of physicists concluded that neutrinos, a kind of subatomic particle, move faster than the speed of light. This was a massive breakthrough, as up until then, nothing had ever been seen as moving faster than light! However, this turned out to be an error. The result of a bad connection between a GPS unit and a computer led to this misleading conclusion.
Examples of Scientific Method in Physics
Let us discuss an example to overview the scientific method. Imagine you are travelling around the world, visiting different places. You enjoy having tea and you frequently boil water wherever you go. As you notice that the boiling point of water is different sometimes, you decide to use the scientific method to find out what is going on.
Observation: the water boiled at a lower temperature when I was visiting the mountains than when I was in other cities with low altitudes.
Question: Why does my water boil at different temperatures?
Research: In a chemistry book, you read that the boiling temperature of a substance depends on the strength of the molecular bonds of a substance and the pressure.
Hypothesis: Since the atmospheric pressure changes with altitude, the boiling temperature of water is different at different altitudes.
Experiment: You decide to heat water at different altitudes and record the boiling temperature.
Analysis:
Altitude \( \text{m} \) | Boiling point of water \( \text{C}^\circ \) |
0 | 100 |
150 | 99.5 |
305 | 99 |
610 | 98 |
1524 | 95 |
Your measurements indicate that as the height increases, the boiling temperature of water decreases!
Conclusion: The original hypothesis was correct. The boiling temperature of water changes with altitude following an approximately linear relationship: per every \( 300 \; \mathrm{m} \) the boiling temperature decreases approximately by one degree Celcius.
You are ready to tell your friends about your findings!
Scientific Method Physics - Key takeaways
- The scientific method is an ordered series of steps to acquire knowledge based on experimental evidence.
- The steps of the scientific method are:
- Ask a question about something you observe.
- Do background research to learn what is already known about the topic.
- Construct a hypothesis.
- Experiment to test your hypothesis.
- Analyze the data from the experiment.
- Draw conclusions.
- A hypothesis is an assumption we make to explain our observations.
- The type of hypothesis that the scientific method requires needs to be able to be proven false by experimentation, and it is known as a falsifiable hypothesis.
- A good experiment needs to be precise, controlled, and reproducible under the same conditions.
References
- Fig. 1 - The Scientific Method (simple).png (https://commons.wikimedia.org/wiki/File:The_Scientific_Method_(simple).png) by Thebiologyprimer is licensed by CC0 1.0 (https://creativecommons.org/publicdomain/zero/1.0/deed.en)
- Fig. 2 Scientists working concept by Freepick (https://www.freepik.com/free-vector/scientists-working-concept_7406886.htm).
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