Scientific Method



Science investigations start by making some initial observation about a problem or natural phenomenon that needs to be solved. Observation involves using one or more of the senses (sight, hearing, taste, touch, smell) to gather information. Some initial information, research or data, may be collected to learn more about this observation or question.


A hypothesis is a testable explanation. When enough information is gathered, a hypothesis can be made. A hypothesis is a possible explanation for a set of observations or an answer to a scientific problem that can be tested.

  1. A hypothesis may arise from prior knowledge, logical inferences, or imaginative guesses.
  2. A hypothesis is useful only if it can be tested, usually by an experiment.
  3. A hypothesis must be falsifiable.   This means you must be able to demonstrate that it is false if it is untrue.
  4. Testing the hypothesis can be done by making further observations or through careful questioning.
  5. A tested hypothesis is valuable to scientists because it helps to advance scientific knowledge.

A hypothesis is frequently written as an “If, then” statement. IF “X” is changed, THEN “Y” will result.


Next, a scientist may want to test that hypothesis. We will focus on controlled experiments to test hypotheses for most of this course; controlled experiments test one variable and measure the effect of this variable. Controlled experiments should be repeatable by other scientists. You will learn how to properly design controlled experiments later in this module.

Collect, Organize and Interpret Data

Information gathered in an experiment is called data. Data can be classified into 2 types:

  1. Quantitative : involving numbers (like counting or measuring objects); metric units are used (gram, meter, liter)
  2. Qualitative : involve characteristics that cannot be easily measured or counted.

It is important for a scientist to be objective and avoid bias (such as personal opinion) when making observations. When scientists collect data, they are trying to find out if certain factors changed or remained the same. The best way to do this is to make a graph or a data table.

  1. A data table displays rows and columns of information. It is often used when collecting data or can be used to display data in a scientific report.
  2. A graph of the data can make patterns or relationships much easier to recognize. They can represent many numbers at once.

Scientists draw a conclusion or interpret data based upon their results.

  1. Scientists evaluate if the data fit the hypothesis and draw a conclusion by stating whether the hypothesis was supported or refuted.
    1. If supported – it is reviewed and re-tested by other scientists to verify the results
    2. If refuted – scientists may adjust the original hypothesis and re-test
  2. Errors are noted
  3. More questions may be posed


Communicate Findings

Science is a collective task. The ultimate goal of science is to share information and move in the direction of progress. Scientists share their findings by publishing and presenting their research.

This step also allows a scientist’s study to undergo peer review. This means that other scientists attempt to repeat and evaluate your findings to determine if they are scientifically sound.