Scientific investigation begins with an observation followed by asking a question about what has been observed.
Steps of the scientific method
The first step in the scientific method is to make an observation about something that interests you. Your observation can be on anything from plant movement to animal behavior, as long as it’s something you really want to know more about. This is where you come up with the idea for your science project.
After you have made your observation, you need to ask a question about what you have observed. Your question should indicate what you are trying to discover or achieve in your experiment.
When asking your question, you should be as specific as possible. For example, if you are doing a project on plants, you may want to know how plants interact with microbes. Your question may be: Do some plant species inhibit bacterial growth?
The hypothesis is a key component of the scientific process. A hypothesis is an idea that is suggested as an explanation for a natural event, a particular experience, or a specific condition that can be tested through definable experimentation.
State the purpose of your experiment, the variables used, and the predicted outcome of your experiment. It is important to note that a hypothesis must be verifiable. That means you should be able to test your hypothesis through experimentation.
An example of a good hypothesis is: If there is a relationship between listening to music and heart rate, then listening to music will cause a person’s resting heart rate to increase or decrease.
Once you have developed a hypothesis, you must design and conduct an experiment to test it. You must develop a procedure that clearly states how you plan to conduct your experiment.
It is important that you include and identify a controlled variable or a dependent variable in your procedure. Controls allow us to test a single variable in an experiment because they are not modified.
We can then make observations and comparisons between our controls and our independent variables (things that change in the experiment) to develop an accurate conclusion.
Results are where you report what happened in the experiment. That includes the detail of all the observations and data made during your experiment. Most people find it easier to visualize data by plotting or graphing the information.
The final step of the scientific method is to develop a conclusion . This is where all the results of the experiment are analyzed and a determination is made on the hypothesis. Did the experiment support or reject your hypothesis? If your hypothesis was supported, great. If not, repeat the experiment or think of ways to improve your procedure.
Scientific method example
- Raspberries did not grow well this year.
- Why didn’t the raspberries grow well this year?
- The raspberries didn’t grow well because it didn’t rain much.
- Raspberry plants are placed in moderately lit areas and they all receive the same amount of light each day. Each plant will receive a different amount of water. The size of the berries will be recorded daily once the plants begin to produce berries.
- Raspberry plants that received 1 cup of water daily increased to 1/2 “in diameter and those that received two cups of water increased to 3/4” in diameter.
- The raspberry plants that receive the most water grow the most. Therefore, the hypothesis is supported that this year’s raspberries did not receive enough rain.
Another example of a scientific method
Scientist Edward Jenner lived in England during the seventeenth and nineteenth centuries, when smallpox was a deadly disease for people, killing 30% of those infected and leaving scars in the survivors, or causing blindness.
However, smallpox in cattle was mild and could be spread from cow to human by sores located on the cow’s udders. Jenner found that many dairy workers claimed that if they had caught smallpox from cattle (which healed quickly) they would not get sick from human smallpox.
- Observation : Belief of immunity obtained from the contagion of smallpox of cattle. Based on this observation, Jenner went on to the next step in the scientific method, holding the hypothesis that this belief was true and developing the necessary experiments to prove or disprove it.
- Hypothesis : The contagion of cattle pox gives immunity to human smallpox.
- Experiment : Jenner’s experiments would not be accepted today, as they were performed on humans. Although at that time there was no other way to test the hypothesis, anyway, experimenting with a child today would be completely inadmissible.
Jenner took material from the smallpox sore from the hand of an infected milkmaid and applied it to the arm of a boy, the son of her gardener. The boy became ill for several days, but then made a full recovery. Later Jenner took material from a human smallpox sore and applied it to the arm of the same child, observing no contagion of the disease. After this first test, Jenner repeated the experiment with other humans and then published his findings.
- Conclusions : confirmed hypothesis. Therefore, (deductive method) infecting a person with cowpox protects against human smallpox infection. Later, the scientific community was able to repeat Jenner’s experiments and obtained the same results.
In this way the first ” vaccines ” were invented : applying a weaker strain of a virus to immunize the person against the strongest and most harmful virus. Currently the same principle is used for various diseases. The term “vaccine” comes from this first form of immunization with a bovine virus.