This week, we learned about theories, hypotheses, and laws in science. This is a summary of this topic.
Facts
- A basic statement established by experiment or observation.
- All facts are true under specific conditions.
- Some facts may be false when re-tested with better instruments.
- Example: Banana is yellow, 365 days in a year
Theories
- Theories are an explanation of natural phenomena.
- An explanation for why certain laws and facts exist that can be tested to determine its accuracy.
- It is not a prediction although we use theory to make predictions.
- It can be used to make predictions about the way things are and how they will be.
- Theories aren't likely to change. They have so much support and are able to explain satisfactorily so many observations, that they are not likely to change.
- One scientist cannot create a theory; s/he can only create hypotheses.
- Example: Big Bang Theory, Cell theory
Hypotheses
- A tentative statement such as ‘if A happens then B must happen’ that can be tested by direct experiment or observation.
- A proven hypothesis can be expressed as a law or a theory.
- A disproven hypothesis can sometimes be re-tested and found correct as measurements improve.
- It can be classified as an educated guess, a suggested solution based on evidence to be a scientific hypothesis.
- A hypothesis is very tentative; it can be easily changed.
- Example: If I give a plant an unlimited amount of sunlight, then the plant will grow to its largest possible size.
Laws
- A statement that describes some aspect of a phenomenon that is always true.
- A logical relationship between two or more things that are based on a variety of facts and proven hypotheses.
- It is often a mathematical statement of how two or more quantities relate to each other.
- A law governs a single action or situation, whereas a theory explains an entire group of related phenomena. (Mendel’s Laws versus Darwin’s Theory of Evolution by Natural Selection)
- Example: Law of Gravity, Newton's Laws of Motion
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