Fact vs. Opinion: Theory, Hypothesis, and Bias

Emphasize the differences between a theory and a hypothesis to teach your class how to avoid scientific bias.

By Lynsey Peterson


Kids in the science classroom

In science, distinguishing fact from fiction is at least as important as it is in other subjects. Because the scientific process actually uncovers facts, the difference between fact and opinion is a crucial distinction. As a teacher, my goal is to teach students how to seek knowledge and learn, not to tell them what to think. However, this does not mean that I must give equal time to all points of view. Oppositional points of view that rely heavily on opinion, or have little convincing evidence, do not deserve the same amount of time in the science classroom as their well-supported counterparts. I find that class time is best spent discovering the basic beauty of the scientific method and the difference between theory and hypothesis

Fact, Opinion, Theory, and Hypothesis

People often confuse the colloquial use of the word theory with its scientific use. They think that a scientific theory is not much more than a hypothesis. It is important to discuss the differences between the scientific use of the terms theory and hypothesis. I relate the difference between a scientific theory and a hypothesis to the difference between a fact and an opinion. Scientific theories are extremely well-supported and have been proven many times, in many ways, by many scientists. They are as close to fact as science can get, considering that the beauty of the scientific method is that the scientific world is not permanent, but can be revised with new evidence. Hypotheses, on the other hand, are a good prediction of something, but more like an opinion than a fact. Since the integrity of the scientific method is important in the distinctions between hypothesis and theory, the topic also lends itself to a discussion of the problem with opinions and bias in scientific research.

What About Bias?

Bias in science is a real problem. Many findings have later been refuted because flaws have been uncovered with the research. Because science is a team sport, scientists share their work with others who can replicate, and either confirm or deny their findings. Good scientists work to eliminate bias from their experiments. Still, the incentives for positive findings can make scientists prone to unintentional bias. I have even experienced this during experiments in my classroom. Young scientists want to get the right results so badly that they get upset when their experiment does not go according to plan. I use this as a learning experience to help us remember that positive, negative, and inconclusive results can all be useful in the pursuit of scientific knowledge.

Another way to teach your class about the importance of eliminating scientific bias is to help them recognize bias and its implications. Have small groups research the types of biases that can confound scientific experiments. Then, give them examples of flawed experiments. Let them work to determine the types of bias present in the study and what could be done to reduce or eliminate it. The groups can also discuss why bias can either intentionally or unintentionally creep into experiments and how it makes science less reliable. At the end of the lesson, have each student write about how they can work to avoid bias in their own scientific experiments. Or, for added creativity, they could create a short story about a biased scientific study and its implications.

Exploring facts, opinions, and bias in science will open a window for your class to the world of scientific research and ethics. Regardless of their future careers, your students will benefit from this understanding as they learn to think critically about the world around them.

Lesson Plan Ideas 

Theory, Theory, Who's got the theory?

Groups present and discuss five different explanations for the origin of life on Earth.  They evaluate the explanations to determine their merit by applying the scientific use of the term theory.  

What Is the Nature of Science?

Personal observations and video clips are used to enhance the understanding and abilities of young scientists in your classroom.  This is a great introductory lesson for a science class. Various resources and extensions are included.

Can You Detect Bias?

Scientific knowledge is applied to a real-world scenario as learners work to identify bias in an investigation. Useful extension activities, interdisciplinary connections, and all relevant materials are provided.

Bias Sampling

Elementary-aged scientists can explore bias first-hand by conducting surveys that ask questions in different ways.  They compare their results and draw conclusions.

Biology Guide

Lynsey peterson picture thumb

Lynsey Peterson