Scientific method


Scientific method
Science and things that are not science (such as pseudoscience) is often defined by whether they use the scientific method.
Not all scientists use the above "scientific method" in their day to day work. Sometimes the actual work of science looks nothing like the above. But on the whole it is thought to be a good method for finding out things about the world which are reliable, and is the model for thinking about scientific knowledge usually used by scientists.
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Example: Dissolving sugar in water.
Let's say we are going to do an experiment to find out what things might change how sugar dissolves in a glass of water. Below is one way to do this, following the scientific method step by step.
Aim.
Does sugar dissolve faster in hot water or cold water? Does the temperature affect how fast the sugar dissolves? This is a question we might want to ask.
Creating a hypothesis.
Now that we have the question, we need to come up with a hypothesis which can be tested. One hypothesis might be: "Sugar will dissolve faster in hot water than cold water." (It could be the opposite just as well.) This can be tested: either sugar will dissolve faster in hot water than cold water, and prove our hypothesis correct, or it may dissolve faster in cold water, or it may dissolve at the same speed in both, proving our hypothesis wrong. In any case we will know part of the answer to our first questions.
Planning the experiment.
One simple way to create an experiment would be to dissolve sugar in water of different temperatures and to keep track of how much time it takes for the sugar to dissolve.
We will want to make sure that we use the exact same amount of water in each trial, and the exact same amount of sugar. If we did not have the same number of either, we might influence the experiment in a way that would make it impossible to tell if the change in temperature was what was changing the speed of dissolving. To be extra careful, we would also run the experiment in a way that the water temperature does not change during the experiment.
This is called "isolating one variable" ' which means making sure that only one thing is being changed each time.
Running the experiment.
We will do the experiment in three trials, which are exactly the same, except for the temperature of the water.
Drawing conclusions.
If every other part of the experiment was the same (we did not use more sugar one time than the other, we did not stir one time or the other, etc.), then this would be very good evidence that heat affects how fast sugar is dissolved.
We cannot know for sure, though, that there is not something else affecting it. An example of a "hidden cause" might be that sugar dissolves faster each time more sugar is dissolved into the same pot. This is probably not true, but if it were, it could make the results exactly the same: three trials, and the last one would be fastest. We have no reason to think that this is true at this time, but we might want to note it as another possible answer.
If we wanted to, we might create a new experiment, where we would try to dissolve sugar in the same pot three different times at the same temperature. By not changing the temperature, we would know if it was the pot which was causing the change in dissolving, if there was any change at all. But this would be a different experiment. This example is just meant to show how the results of one scientific experiment can lead to another brand-new experiment.
Writing up the results.
When writing up the results we would describe exactly what we did, from the first step, including: why we asked the question; what we assumed when asking it; what our hypothesis was; what our experiments were; how we ran the experiments; what the results were (our data table would make them easy for others to read); and what our conclusions were. In the end, our hypothesis seems to be correct. After writing up our conclusions, we would, if we were professional scientists, send them to other scientists to look at, to see if it sounded right to them. Maybe they would have suggestions, or get ideas for new experiments. If we were professional scientists, we would probably have the results published in a research journal, where other scientists would have a chance to agree or disagree. It doesn't matter if other scientists find us out to be wrong later, because this is how knowledge grows in science.


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