What is a fact?
Science is different from other ways of thinking. It is based on facts. Gravity is a fact. If you let go of a ball, it will fall to the ground. Can you tell a fact from an opinion? Can you tell when an idea follows logically from a fact? Basing ideas on facts is essential to good science.
Facts, Observations, Opinions
Science is a set of facts, and it is also a set of explanations that are based on those facts. Science relies on facts to explain the natural world.
Scientists usually begin an investigation with facts. A fact is a bit of information that is true. Facts come from data collected from observations. Facts can also come from experiments that have been run. Data is factual information that results from an investigation. Facts and data are not subject to opinion or bias. An opinion is someone's subjective view or position on a subject.
What is a fact? Look at the following list. Identify if the statement is (1) a fact (from observation or prior experiments), (2) an opinion, or (3) a combination.
Can you be sure from the photo that Susan has a cold?
- Susan (Figure above) has black hair.
- Susan is sneezing. She has a cold.
- Colds are caused by viruses.
- Echinacea is an herb that prevents colds.
- Bill Gates is the smartest man in the United States.
- People born under the astrological sign Leo are fiery, self-assured, and charming.
- Average global temperature has risen since 1900.
The following is an analysis of the statements above:
- This is a fact. The fact comes from observation.
- The first sentence is a fact from observation. The woman is sneezing. The second sentence is an opinion. She might have a cold, or she might have allergies or the flu. Tests could be done to see what is causing her illness. This opinion could become fact if the tests show that she actually has a cold, or it could be proven wrong.
- This is a fact. Many, many scientific experiments have shown that colds are caused by viruses.
- This statement sounds like a fact. However, the scientific evidence is mixed. One reputable study published in 2007 showed a decrease in colds of 58% in people who used echinacea. Several other studies have shown no beneficial effect.
- Bill Gates is the wealthiest man in the United States; that’s a fact. However, there’s no evidence that he’s also the smartest man; this is an opinion.
- This sounds like a fact, but it is not. There must be data to support the statement. How would you test it? Gather together a large number of subjects, each with a friend. Have the friends fill out a questionnaire describing the subject. Match the traits against the person’s astrological sign. Do the astrological predictions fit? Are Leos actually more fiery, self-assured, and charming? Tests like this have not supported the claims of astrologers. However, astrologers have not modified their opinions.
- This is a fact. The following graph shows the temperature anomaly since 1880 (Figure below). There’s no doubt that average global temperature has risen since 1880. The largest rise has been since the late 1970s.
Global average annual temperatures are rising. This graph shows temperature anomaly relative to the 1951-1980 average (the average is made to be 0). The green bars show uncertainty.
- Facts are true. Data, gathered correctly, is factual. Facts and data are not subject to opinion or bias.
- Facts can be determined by observations or experiments.
- Some statements that appear to be facts are not.
- All scientific explanations and interpretations are based on facts.
- What is a fact? What is data? What is an opinion? How can you tell them apart?
- Why are facts and data important to science?
- How might a fact be disproved? Are there some facts that will never be disproved?
Use this resource to answer the questions that follow.
- How do we use science every day?
- What is science?
- What is the scientific process?
- Define science.
- What are the rules of science?