In the scientific community, "theory", "law" and "fact" are technical terms with distinct and complex meanings. Many people with no scientific background, including high school and college students, do not have a clear understanding of the differences between these three terms, as do many adults; all of them can benefit from a simple and clear explanation. This article will help you understand and explain the differences between the appropriate scientific uses of each of the three terms.
Steps
Method 1 of 3: Explain the Difference Between Scientific Theory and Law
Step 1. Define a scientific law
Understanding a law is fundamental to assimilating scientific terminology: in science, a law is a statement based on repeated long-term observations, which describes any phenomenon of nature.
- Laws have never been refuted (hence their relatively small number) and they are not explanations: they are descriptions and are often enunciated through relatively simple mathematical equations.
- Scientific laws, despite their formality, can change or foresee exceptions as scientific interpretations of phenomena evolve.
Step 2. Provide examples of laws
Helping someone understand a scientific law - a certainly abstract concept - will allow them to distinguish between theory and fact. In many respects, laws are a starting point; they are often observed and have never been refuted, but they do not explain why something happens.
For example, the law of universal gravitation has been known in the scientific community since the end of the 17th century. It describes the natural phenomenon of gravity, but does not provide an explanation for how and why gravity works
Step 3. Define a scientific theory
Scientifically speaking, a theory is a rational explanation of why an aspect of our world works in a certain way. The definition of a theory will incorporate facts and laws, although these three elements are fundamentally separate.
- A theory is based on initial hypotheses (assumptions) and can be revised in accordance with the development of scientific understanding of the cause of a phenomenon.
- A theory is confirmed by all available evidence, so that it can be used to predict new, not yet observed phenomena.
Step 4. Give an example of scientific theory
This will help you clarify your speech and provide a clearer explanation. The theory is used to explain an event, while the law describes a natural phenomenon in specific circumstances.
For example, the scientific theory of natural selection corresponds to the law of evolution. While the law states an observed natural phenomenon (life forms develop new characteristics based on external circumstances), the theory describes how and why this happens
Method 2 of 3: Explain the Difference Between Law and Fact
Step 1. Define a scientific fact
In scientific terminology, a fact is an observation which has been repeatedly made and which is accepted as functioning in practice and "correct".
While the facts may be scientifically disproved or may not be consistent in time and space, they are believed to be true until disproved
Step 2. Provide examples of scientific facts
As you explain this concept, especially focus on the distinction between fact and law, as both describe natural phenomena, albeit in different ways.
- When explaining a fact, start with a general point of view.
- For example, start your explanation by saying something like: "At noon there is always light". This is a fact, as it describes a state of nature, however this statement may not be true in Antarctica or Greenland, where darkness lasts all day in certain seasons.
- He explains how this will lead to a revision of the scientific fact: "Within certain degrees of latitude, there is always light at noon".
Step 3. Clarify the distinction between scientific laws and facts
Facts are often the initial building blocks of a scientific investigation; they can generate curiosity and hypotheses that derive from research and experimentation.
- Facts are less formal than laws and are not seen as an "official" definition of a phenomenon or why something happens.
- The facts are more localized and less general than the laws. Explain that if the Law of Evolution describes how species around the planet evolve over time, a scientific fact related to evolution (and natural selection) could be: “Long-necked giraffes can reach more leaves than giraffes with short necks”.
Step 4. Eliminate any misconceptions
Students and adults happen to misunderstand scientific vocabulary, misunderstanding the relationship between theories, laws and facts.
For example, scientific theories do not develop into scientific laws. To explain the difference, focus on this distinction: laws describe phenomena, theories explain phenomena, and facts describe observations
Method 3 of 3: Explain Scientific Theories, Laws and Facts in the Classroom
Step 1. Ask your students to define some scientific theories
You can start from understanding them to develop a more refined definition of "theory". A good definition should make it clear that a scientific theory is a statement intended to explain natural phenomena. Make the following clear to your students:
- A theory is worth very little if it does not properly consider all known evidence.
- Theories are subject to change as new evidence becomes available (most of the theories you will discuss in class in high school are solidly confirmed and are unlikely to be significantly revised).
Step 2. Ask students to name some scientific theories
You will get some common answers, such as:
- The theory of relativity - the laws of physics are the same for all observers.
- The theory of evolution by natural selection - the changes observed in species occur due to the selection of better adapted specimens.
- The Big Bang Theory - the universe began as an infinitely small point that underwent expansion to form the universe as we know it today.
Step 3. Define a scientific fact for your students
A fact is an objective, verifiable observation, identical everywhere. It can be verified many times, and it did.
- For example, we know that the "germ theory of disease" is a fact, because we can take the bacteria from someone who suffers from a disease, look at that bacterium under a microscope and then inject it into another individual, who will contract the same disease..
- We know the Earth is round because we can travel west back to where we started from.
Step 4. Make it clear that theories can never be turned into fact
These are two fundamentally different elements. Remember: a theory is a general statement meant to explain the facts. As a useful example, introduce your students to the development of heliocentric theory and the facts that inform it.
- The peoples of antiquity noticed curious points of light that "wandered" in space (today we know that they were the planets).
- Planets move across the sky because, like Earth, they orbit the Sun, each at a specific speed and at a different distance from the Sun.
- Nicolaus Copernicus is generally considered the first who proposed this theory by supporting it with concrete evidence, but ancient populations came across this same theory through observation.
- We now consider it a fact because we have sent spaceships into space and we can predict the movements of the planets with very high accuracy. Of course, our predictions come from theory (and the laws behind that theory).
Step 5. Define a scientific law
This is a complicated concept that tends to confuse students. Laws tend to be mathematical in nature and usually stem from simple statements about mathematical systems and their behaviors. Explain that, like a theory, a law can also be used to make predictions, but the primary purpose of a law is to describe natural phenomena. Here are some examples of scientific laws.
- Newton's law of cooling and heating: the temperature variation of two bodies in thermal contact is proportional to their temperature difference.
- Newton's laws of motion: statements about how large objects made of atoms behave when they move at low speeds relative to each other.
- Laws of thermodynamics: statements on entropy, temperature and thermal equilibrium.
- Ohm's Law: the voltage at the extremes of a purely resistive element is equal to the current flowing through the element multiplied by its resistance.
Step 6. Discuss how theories are created and evolve
First of all, a theory is built from facts; facts precede and inspire a theory. Second, theories contain laws, but laws mean very little without supporting facts. The theories also contain logical inferences.
- For example, it must be inferred that derived laws actually predict facts. By accumulating all previous knowledge, a scientist makes a general statement to explain all the evidence.
- Other scientists confirm the facts and use the theory to make predictions and get new facts.
