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Scientific method
Scientific method
Scientific method is the steps that scientists use to acquire knowledge about our natural world. There are numerous different variations of scientific method, from one field to another, but generally, it includes the following steps:
- Making observation and asking a question
- Doing background research
- Proposing a hypothesis
- Doing experiments
- Analysing results and drawing a conclusion
Variables
Variables
While designing a scientific investigation, it is very important to identify different variables of the experiment.
For example if we set up an experiment to investigate the importance of water to the growth of plant, we have to set up 2 types of setup, providing different amount of water to the plant. The variables of the experiment will be:
- Independent variable - Amount of water provided
- Dependent variable - Rate of growth of the plant
- Controlled variables - Size of the plant, amount of light provided, temperature, humidity, etc.
Scientific controls
Scientific controls
Controlled experiments is a very important concept in scientific investigation. Controlled experiment is a scientific test in which you keep all variables constant except for the one you want to test. It is used to ensure the difference in outcome is due to the change of experimenting circumstances. In general, a control subject group is different in given condition from the test group by only one variable.
Negative control
Negative control
A negative control group is a control group that is not exposed to the experimental treatment or to any other treatment that is expected to have an effect. Therefore, negative control is expected to have negative outcome. If the treatment group and the negative control both produce a positive result, it can be inferred that a confounding variable is involved in the phenomenon under study, and the positive results are not solely due to the treatment. If the effect of treatment is measured as parameters such as lengths, times, percentages, etc., the treatment is inferred to have no effect when the treatment group and the negative control produce the same results.
You can watch a video about the concept and example set-up of a negative control in the link below.
Positive control
Positive control
Positive controls are very helpful because it allows experimenters to be sure that their experimental set-up is working properly, i.e. testing the validity of the test. A positive control group is a control group that is not exposed to the experimental treatment but that is exposed to some other treatment that is known to produce the expected positive effect. If the positive control does not produce the expected result, there may be something wrong with the experimental procedure, and the experiment is repeated. For difficult or complicated experiments, the result from the positive control can also help in comparison to previous experimental results.
You can watch a video about the concept and example set-up of a positive control in the link below.
Minimizing error
Part of the content form BIOLOGY FOR LIFE (https://www.biologyforlife.com/error-analysis.html) Minimizing error
All scientific investigations have errors to some degree. An error is the difference between a measurement and the true value being measured. Note that, errors are not mistakes made due to carelessness, sloppiness or being rushed.
There are two major kinds of error in measurement, namely systematic errors and random errors. Systematic errors are faults or flaws in the investigation design or procedure that shift all measurements in a systematic way so that in the course of repeated measurements the measurement values are constantly displaced in the same way. Systematic errors can be eliminated with careful experimental design and techniques. Random errors are caused by unknown and unpredictable changes in a measurement, either due to measuring instruments or environmental conditions. You can't eliminate random errors. You can reduce the effect of random errors by taking multiple measurements and increasing sample sizes.
Writing a scientific investigation report
Writing a scientific investigation report
A scientific investigation report is a written report telling other scientists about your work. You have to deliver clearly and communicate effectively what you have accomplished in your investigation. Scientific investigation reports published in a scholastic environment, so called papers, also affect your reputation as a scientist.
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