Hypothesis? Law? Theory? . . . Huh?

The three science terms in the title are a major source of confusion for many science students. Be confused no longer . . .

HYPOTHESIS > An idea or question that can be tested (proved or disproved) by experiment. A written statement that predicts the effect that a change in a manipulated (independent) variable will have on a measurable, responding(dependent) variable in a controlled experiment.

LAW > A descriptive rule for a specific behavior that is always obeyed in nature. There are no exceptions to scientific laws; they are carved in stone! Unlike the laws of man, scientific laws can never be broken.

THEORY > A detailed and complex, scientific explanation supported by nearly definitive evidence. Scientific theories are nothing like the “theories” of non-scientists, which are more like informal hunches made regarding a mysterious occurrence. An accepted theory in science has usually been proven to be accurate leaving no room for doubt.

As usual, definitions are best understood with simple clear examples:

HYPOTHESIS

If sunflower plants are over-crowded, then their vertical growth (height in m) will be stunted.

LAW

The 2nd Law of Thermodynamics states that, “Heat naturally moves from warmer regions to cooler regions”.

Some Important Scientific Laws:

BIOLOGY: Mendel’s Laws of Genetic Inheritance

CHEMISTRY: The Law of Conservation of Atoms

GEOLOGY: The Law of Superposition in Rock Strata

PHYSICS: Newton’s Law of Universal Gravitation

ASTRONOMY: Kepler’s Laws of Planetary Motion

THEORY

The Theory of Plate Tectonics describes in accurate detail the composition, boundaries, and motions of Earth’s rocky tectonic plates – and explains how and why these plate movements produce sea-floor spreading, mountain formations, volcanism, earthquakes, the rock cycle, and other geologic features and processes.

Some Important Scientific Theories

BIOLOGY: The Theory of Natural Selection and Evolution

CHEMISTRY: Atomic Theory

PHYSICS: Einstein’s Theory of General Relativity

ASTRONOMY: The Big Bang Theory

GEOLOGY: The Theory of Geologic Change