Scientific Method

Scientific Method Scientists use the scientific method to study observations and answer questions. © Olivier Le Moal

Scientists have a special way of learning about the world. It is called the scientific method. The scientific method has five main steps. By following these steps, a scientist can learn and discover new things.

Scientists begin by looking at the world. They notice things they do not understand or cannot explain. From there, they can ask why certain things work the way they work. They can also ask why certain things happen or do not happen.

The best questions are very focused. For example, a scientist might ask: Does salt affect how fast water freezes? This question has what are known as variables. In science, a variable is something that changes, or can be changed. In this example, the salt in the water is the variable. A scientist could test to see how fast saltwater freezes. Then, they could test to see how fast freshwater freezes and compare the outcomes.

The scientific method creates a test that tries to answer a question. To create a test, a scientist must first guess what the answer might be. This guess is called a hypothesis.

The hypothesis is very important to the scientific method. It is what allows the scientist to create a test. For example, consider the question, “Does salt affect how fast water freezes?” The hypothesis might be no, salt does not affect how fast water freezes. A scientist could then set up a simple test. The test would involve putting freshwater and saltwater in a freezer at the same time. Then, the scientist would test to see which one freezes first.

Some questions only require a scientist to carry out a simple test and watch what happens. Other questions are more difficult. Scientists need data and evidence to answer them. Data is the information a scientist gets from carrying out tests. It involves facts that are recorded, often as numbers. Evidence is anything that seems to support or not support a hypothesis.

There is an important difference between data and evidence. Data is raw information. It does not involve any form of judgment. Evidence is usually drawn from data. It involves judging the data in a certain way to see whether it supports the hypothesis.

Judging test data involves studying it. Scientists study data to draw evidence in many ways. They look for patterns. They look for connections between things that happened during the test. They compare the outcomes of certain tests to other tests. They can create graphs or diagrams that display data in visual forms. These methods all help scientists understand data better. By understanding the data, they can find evidence that supports or does not support the hypothesis.

In the final step, the scientist answers the question they asked at the outset. This answer is drawn from the data and evidence they got during testing. That data and evidence will show the hypothesis to be right or wrong. In some cases, it may not be clear whether the hypothesis was right or wrong. If this happens, the scientist must find a different question to ask and carry out more tests.