Scientific Theories & Laws
Adapted from work by
Randy Bell
Oregon State University
How are these concepts related to each
other?
Common ideas
Speculation
Fact
Mystery Tube
Mystery Tube
Mystery Tube
Law of Strings
When any short string
is pulled, the long
string shortens by an
equivalent amount.
String Theory
?
Develop Your Own Model
 Plan
 Then build
 Try it out… does it work like the Mystery Tube…
 A little bit?
 A lot?
 Completely?
Share Your Model
 Describe what the inside of your tube looks
like
 What was your reasoning for this
configuration?
 To what extent does your model work like
the mystery tube?
Competing Scientific Theories/Models
Common ideas
Speculation
Fact
From where do these ideas originate?
Laws in Media
Explicit Instruction
Answer:
A law is something that can be measured or
observed to be true. A theory is something that
can only be assumed to be true based on the
best available knowledge. A theory can
eventually, though not necessarily, become a law
after time and scrutiny.
Potential Progression of Scientific Ideas
THEORY
LAW
Explanatory
Descriptive
A theory cannot
become a law
Can come before
a theory… but
A law cannot
become a theory
HYPOTHESIS
Proposed answer to
research question: Testable!
FACTS
Good starting place (sometimes)
Scientific Facts and Hypotheses
Scientific Fact:
“In science fact can only mean confirmed to such a degree
that it would be perverse to withhold provisional consent.”
Stephen J. Gould
Scientific Hypothesis:
1. A proposed answer to a research question
2. A tentative explanation for an observation or
phenomena that can be tested through experimentation
Scientific Theories & Laws in the Standards
Theories
Laws
Theory of Plate Tectonics: Earth’s crust
is divided into plates that move. Explains
why earthquakes and volcanoes occur in
certain zones.
Newton’s Laws of Motion:
Describe the relationship between the
forces acting on a body and its motion
due to those forces.
Cell Theory:
Identifies cells as the fundamental unit of
structure and function in living things.
Explains that new cells are formed from
other existing cells.
Ideal Gas Law: PV=nRT
Describes the relationship between
pressure, volume, moles, and
temperature of a gas.
Darwin’s theory of natural selection:
Explains the diversity of life in terms of
competition, survival, and inherited traits.
Mendel’s Laws of Inheritance:
Describes how hereditary
characteristics are passed from parent
organisms to their offspring.
Atomic Theory:
All matter is composed of elements made
up of atoms. Explains why matter is
conserved in chemical reactions.
Law of Superposition:
Describes the general principle that in
undeformed layers of rock, the oldest
rock will be at the bottom.
Theories
Laws
Theory of Plate Tectonics: Earth’s crust
is divided into plates that move. Explains
why earthquakes and volcanoes occur in
certain zones.
Newton’s Laws of Motion:
Describe the relationship between the
forces acting on a body and its motion
due to those forces.
Cell Theory:
Identifies cells as the fundamental unit of
structure and function in living things.
Explains that new cells are formed from
other existing cells.
Ideal Gas Law: PV=nRT
Describes the relationship between
pressure, volume, moles, and
temperature of a gas.
Darwin’s theory of natural selection:
Explains the diversity of life in terms of
competition, survival, and inherited traits.
Mendel’s Laws of Inheritance:
Describes how hereditary
characteristics are passed from parent
organisms to their offspring.
Atomic Theory:
All matter is composed of elements made
up of atoms. Explains why matter is
conserved in chemical reactions.
Law of Superposition:
Describes the general principle that in
undeformed layers of rock, the oldest
rock will be at the bottom.
Theories Explain Observations
Theory of Plate Tectonics: Earth’s crust
is divided into plates that move.
Explains why earthquakes and
volcanoes occur in certain zones.
Cell Theory:
Identifies cells as the fundamental unit of
structure and function in living things.
Explains the structure of life and where
new cells come from.
Darwin’s theory of natural selection:
Explains the diversity of life in terms of
competition, survival, and inherited traits.
Explains the fossil record and how
species can change over time.
Atomic Theory:
Matter is composed of discrete units called
atoms, as opposed to the obsolete notion
that matter could be divided into any
arbitrarily small quantity
Explains why matter is conserved in
chemical reactions.
Theories Explain Laws
Einstein’s General Theory of Relativity:
Law of universal gravitation:
Explains gravity in terms of space-time
curvature and that space-time is curved by
matter.
Describes the relationship between
mass, distance, and the force of gravity.
Chromosome Theory: chromosomes are
the basis for all genetic inheritance.
Explains the mechanism underlying
Mendel’s laws.
The law of independent assortment:
Describes the principle that traits are
passed on to offspring independent of
each other .
Kinetic Molecular Theory: Matter
consists of tiny particles in constant
motion, whose speed is proportional to the
absolute temperature. Explains gas laws.
Boyle’s Law:
Describes the relationship between
pressure and volume of a gas when
temperature is held constant.
BEFORE Instruction (WRONG)
Quotes from Students & Teachers
“A scientific law is a theory that has been proven over and
over by different scientists.”
“A scientific law is definite, and nothing is named a law unless
scientists agree that there is no question to its being true. For
example, scientists are open to finding new information about
the atomic theory, but Newton’s law of motion has been tested
enough times that scientists are certain it is true.”
“Newton’s 1st Law is proven and through various testing and
experiments it has come to be known as a proven law.
Theories, however, have not been proved enough to be
changed into laws.”
AFTER Instruction
Quotes from Students & Teachers
“Scientific theories never turn into laws.”
“A scientific law is often mathematical and is used to
describe a pattern found in nature. A theory is used to try
and explain the ‘why’ of a pattern or occurrence.”
“A scientific law is a statement describing how something
works. A scientific theory attempts to explain something
that cannot be directly observed. Laws are usually
something that is observable. Theories are based on
inference, an effort to explain something.”
Scientific Theory & Law Extension
 Individually:
 Group:
Write a list of key ideas or
create a Venn diagram
focused on scientific
theories and laws.
Discuss your ideas with
your group, adding to and
modifying your list as
needed
Consider how they are
similar and different.
What Qs remain for you
about scientific theories
and laws?
What does the Mystery Tube activity tell us
about what science is like?
What does the Mystery Tube activity tell us
about what science is like?
 A scientific theory and
 Scientific knowledge
law cannot become the
other.
 Why? They serve
different purposes.
 Neither is absolute.
 Both have exceptions and
can change (but don’t
have to change).
(including theories &
laws) is evidence-based.
 All aspects of scientific
work are creative…





Developing Qs
Developing procedures
Problem solving
Data interpretation
Development of models