Chapter 1: The Scientific Method and Early Astronomy

Vocabulary flashcards covering key concepts from Chapter 1 notes.

Scientific Method

An ongoing, organized process for investigating the physical universe through problem formulation, observation, experimentation, interpretation, and testing hypotheses.

Hypothesis

An educated guess that can be tested by experiments or observations.

Theory

A well-developed explanation based on many tested hypotheses and observations; testable and falsifiable.

Observation

Careful noting of phenomena, which may occur without conducting an experiment.

Experiment

Deliberate manipulation of variables to observe effects, often recording quantitative data.

Independent Variable

The variable deliberately changed by the experimenter to test its effect.

Dependent Variable

The variable measured to see how it responds to changes in the independent variable.

Ptolemy

Ancient model with Earth at the center and epicycles to explain planetary motion (geocentric).

Geocentrism

Earth-centered view of the universe.

Copernicus

Proposed the Sun-centered (heliocentric) model of the solar system as an alternative to geocentric theory.

Heliocentrism

Sun-centered model of the solar system.

Retrograde Motion

Apparent backward motion of planets caused by relative orbital motion; explained by heliocentric theory.

Polaris

The North Star; used as a fixed reference point for navigation.

Kepler

Mathematician who refined Copernicus’ model and formulated the three laws of planetary motion.

Kepler's Elliptical Orbits

Planets move in ellipses with the Sun at one focus.

Kepler's Equal Areas

Line from a planet to the Sun sweeps out equal areas in equal times; faster near the Sun.

Kepler's Planetary Period

The orbital period relates to a planet's distance from the Sun in a specific way.

Newton

Physicist who formulated the law of universal gravitation explaining planetary motion.

Gravity

A fundamental force of attraction that acts between masses; one of the four fundamental forces.

Four Fundamental Forces

Gravity, Electromagnetic, Weak Nuclear, and Strong Nuclear forces that govern interactions in the universe.

Tides

Periodic rise and fall of ocean levels caused by the gravitational pull of the Moon and Sun.

SI Units

The International System of Units used worldwide in science (meter for length, kilogram for mass, liter for volume).

Unit Conversions

Factors used to convert quantities between unit systems (e.g., 1 mile = 1.61 km; 1 gallon = 3.79 L).

Measurement

Quantification of physical properties such as distance, volume, mass, and temperature, often shown as graphs or tables.

Objectivity

Principle that science should be free from personal bias; ideas may inform experiments, but outcomes must be determined by evidence.