Category Archives: Scientific Method

Hypothesis Examples

A hypothesis is a prediction in the scientific method.  (NASA/GSFC/Chris Gunn)

A hypothesis is a prediction in the scientific method. (NASA/GSFC/Chris Gunn)

A hypothesis is a prediction of the outcome of a test. It forms the basis for designing an experiment in the scientific method. A good hypothesis is testable, meaning it makes a prediction you can check with observation or testing. Here are different hypothesis examples.

Null Hypothesis Examples

The null hypothesis (H0) is also known as the zero-difference or no-difference hypothesis. It predicts that changing one variable (independent variable) will have no effect on the variable being measured (dependent variable).

  • Plant growth is unaffected by temperature.
  • If you increase temperature, then solubility of salt will increase.
  • Incidence of skin cancer is unrelated to ultraviolet light exposure.
  • All brands of light bulb last equally long.
  • Cats have no preference for the color of cat food.
  • All daisies have the same number of petals.

Sometimes the null hypothesis is used to show there is a correlation between two variables. For example, if you suspect plant growth is affected by temperature, you could state the null hypothesis. Why would you do this, rather than say “If you change temperature, plant growth will be affected”? The answer is because it’s easier to apply a statistical test to show, with a high level of confidence, a null hypothesis is correct or incorrect.

Research Hypothesis Examples

A research hypothesis (H1) is a type of hypothesis used to design an experiment. This type of hypothesis is often written as an if-then statement because it’s easy to identify the independent and dependent variables and see how one affects the other. If-then statements are used to explore cause and effect. In other cases, the hypothesis is stated to show a correlation between two variables. Here are some research hypothesis examples:

  • If you leave the lights on, then it will take longer for people to fall asleep.
  • If you refrigerate apples, they will last longer before going bad.
  • If you keep the curtains closed, then less electricity will be used to heat or cool the house (electric bill will be lower).
  • If you leave a bucket of water uncovered, then it will evaporate more quickly.
  • Goldfish lose their color if they are not exposed to light.
  • Workers who take vacations are more productive than those who never take time off.

Is It Okay To Disprove a Hypothesis?

Yes! You may even choose to write your hypothesis in such a way that it can be disproved because it’s easier to prove a statement is wrong than to prove it is right. In other cases, if your prediction is incorrect, that doesn’t mean the science is bad. Revising a hypothesis is common. It demonstrates you learned something you did not know before you conducted the experiment.

Test Yourself with a Scientific Method Quiz

Scientific Method Quiz

Scientific Method Quiz

Photo: Keith Weller, USDA

This scientific method quiz tests your understanding of the scientific method. The scientific method is a systematic means of exploring the natural world, asking and answering questions, and explaining how things work.

Let’s see how well you understand the steps of the scientific method and what constitutes good science. This is a 10-question multiple choice quiz. If you ace the test, be sure to enter your name in the Leader Board for bragging rights!

This scientific method quiz tests your understanding of the scientific method. The scientific method is a systematic means of exploring the natural world, asking and answering questions, and explaining how things work. Let’s see how well you understand the steps of the method and what constitutes good science!

Steps of the Scientific Method

Scientific Method Steps

Scientific Method Steps (

The scientific method is a system scientists and other people use to ask and answer questions about the natural world. In a nutshell, the scientific method works by making observations, asking a question or identifying a problem, and then designing and analyzing an experiment to test a prediction of what you expect will happen. It’s a powerful analytical tool because once you draw conclusions, you may be able to answer a question and make predictions about future events.

These are the steps of the scientific method:

    • Make observations.

Sometimes this step is omitted in the list, but you always make observations before asking a question, whether you recognize it or not. You always have some background information about a topic. However, it’s a good idea to be systematic about your observations and to record them in a lab book or another way. Often, these initial observations can help you identify a question. Later on, this information may help you decide on another area of investigation of a topic.

    • Ask a question, identify a problem, or state an objective.

There are various forms of this step. Sometimes you may want to state an objective and a problem and then phrase it in the form of a question. The reason it’s good to state a question is because it’s easiest to design an experiment to answer a question. A question helps you form a hypothesis, which focuses your study.

  • Research the topic.

You should conduct background research on your topic to learn as much as you can about it. This can occur both before and after you state an objective and form a hypothesis. In fact, you may find yourself researching the topic throughout the entire process.

  • Formulate a hypothesis.

A hypothesis is a formal prediction. There are two forms of a hypothesis that are particularly easy to test. One is to state the hypothesis as an “if, then” statement. An example of an if-then hypothesis is: “If plants are grown under red light, then they will be taller than plants grown under white light.” Another good type of hypothesis is what is called a “null hypothesis” or “no difference” hypothesis. An example of a null hypothesis is: “There is no difference in the rate of growth of plants grown under red light compared with plants grown under white light.”

    • Design and perform an experiment to test the hypothesis.

Once you have a hypothesis, you need to find a way to test it. This involves an experiment. There are many ways to set up an experiment. A basic experiment contains variables, which are factors you can measure. The two main variables are the independent variable (the one you control or change) and the dependent variable (the one you measure to see if it is affected when you change the independent variable).

    • Record and analyze the data you obtain from the experiment.

It’s a good idea to record notes alongside your data, stating anything unusual or unexpected. Once you have the data, draw a chart, table, or graph to present your results. Next, analyze the results to understand what it all means.

    • Determine whether you accept or reject the hypothesis.

Do the results support the hypothesis or not? Keep in mind, it’s okay if the hypothesis is not supported, especially if you are testing a null hypothesis. Sometimes excluding an explanation answers your question! There is no “right” or “wrong” here. However, if you obtain an unexpected result, you might want to perform another experiment.

    • Draw a conclusion and report the results of the experiment.

What good is knowing something if you keep it to yourself? You should report the outcome of the experiment, even if it’s just in a notebook. What did you learn from the experiment?

How Many Steps Are There?

You may be asked to list the 5 steps of the scientific method or the 6 steps of the method or some other number. There are different ways of grouping together the steps outlined here, so it’s a good idea to learn the way an instructor wants you to list the steps. No matter how many steps there are, the order is always the same.