Key Terms
Introduction
The Nature of Science and Physics
Physics
The science describing interactions of energy, matter, space, and time; focused on the fundamental mechanisms underlying
Classical physics
Developed Renaissance through end of 19th century. Works well for everyday conditions.
Relativity
Use when object travels faster than 1% the speed of light, or experiences a strong gravitational field (near the Sun, fo
Quantum mechanics
Use when objects are smaller than what a microscope can see.
Relativistic quantum mechanics
Combines both; applies to small objects moving at high speeds. Most mathematically complex; only used when necessary.
MODEL
A representation of something too difficult or impossible to observe directly. Accurate only under limited conditions.
THEORY
A broad explanation for patterns in nature; supported by scientific evidence; verified multiple times by multiple resear
LAW
A concise description of a generalized pattern in nature; supported by evidence and repeated experiments. Often expressi
PRINCIPLE
A less broadly applicable statement (Pascal's principle applies only in fluids). The line between law and principle is n
Steps in order
1. Observation 2.
Physical quantity
A characteristic of an object that can be measured or calculated from other measurements.
Fundamental units
Defined only by the procedure used to measure them.
Derived units
Calculated from combinations of fundamental units.
Example
Uncertainty of 0.4 lb on a 5 lb bag = (0.4 / 5) x 100% = 8%