Theories and Laws

The term ‘science’ comes from the Latin scientia, which means ‘a knowledge based on demonstrable and reproducible data’. Reproducible data is used by scientists to develop theories and laws to explain and describe phenomena. Theories provide a coherent understanding of a wide range of phenomena. A law is usually a statement that can be expressed as a mathematical relationship. It describes phenomena in nature, with no exceptions, at a point in time. Testing scientific theories drives scientific breakthroughs and questions current understandings.

Students examine how complex models and theories often require a wide range of evidence, which impacts on society and the environment. In this module, students engage in practical and secondary investigations that are related to major theories or laws and their application.

Investigating Science Syllabus Stage 6 p.43


Introduction to Scientific Theories and Laws

what are the differences between scientific theories and laws?

collect primary data to investigate the law of conservation of mass


collect secondary-sourced data to investigate the theory of plate tectonics

The theory of plate tectonics

"Smithsonian geologist Liz Cottrell of the National Museum of Natural History shows us the tools she uses to learn more about whats buried beneath the Earth's crust."


compare the characteristics of theories and laws

theories vs. laws

"Chat with a friend about an established scientific theory, and she might reply, "Well, that's just a theory." But a conversation about an established scientific law rarely ends with "Well, that's just a law." Why is that? What is the difference between a theory and a law..."

Development of a Theory

what leads to a theory being developed?

gather secondary-sourced data to investigate the supporting evidence and development of theories, including but not limited to:

– germ theory
– oxygen theory of combustion


gather secondary-sourced data to investigate how aspects of a theory can be disproved through the collection of evidence, including:

– Geocentric Theory (of the solar system)
– Theory of Inheritance of Acquired Characteristics
– Dalton’s atomic theory
– Steady State Theory of the Universe (in cosmology)

Source: NASA

Source: NASA

Disproving a theory

"If you were to look up in the eastern sky at the same time each night and note where Mars appears to be compared to the constellations of stars, you would find the planet a little farther east with each viewing. That is, Mars appears to move from west to east from one night to the next.

Every two years or so, there are a couple of months when Mars' position from night to night seems to change direction and move east to west. This strange behavior was very puzzling to early skywatchers. Did the planet really stop, back up, change its mind, and then continue to move forward? Did it have some weird, mystical meaning?

Today we know what's going on. It's an illusion, caused by the ways that Earth and Mars orbit the sun."

Source: NASA; Mars in our night sky. (link below)


Development of Laws

what leads to the acceptance of a scientific law?

gather secondary-sourced data to investigate and assess the evidence that supports scientific laws, including but not limited to:

– Newton’s Second Law of Motion
– Avogadro’s Law
– law of superposition
– Mendel’s Law of Dominance

design and collect primary data to show that results can be predicted by laws, including but not limited to:
– Ohm’s Law
– law of conservation of energy


Applications of Theories and Laws in Science

how are theories and laws used in science?

investigate how the law of conservation of energy is applied in different science disciplines through primary and secondary-sourced research, including but not limited to:

– Chemistry
– Physics
– Human Biology
– Earth and Environmental Science


demonstrate, using evidence and examples, how diverse phenomena have been unified into specific theories, for example:

– atomic theory
– theory of evolution
– Big Bang theory
– plate tectonic theory


gather secondary-sourced data to investigate how scientific investigations of nuclear reactions and decay changed the way in which the law of conservation of mass and law of conservation of energy are interpreted