Chapter 1: Describing the Physical Universe Flashcards

Vocabulary flashcards covering key terms, concepts, measurements, and scientific principles from Chapter 1: Describing the Physical Universe.

SpaceShipOne

The first private aircraft to leave Earth's atmosphere and enter space, accomplishing this feat on June 21, 2004.

Physics

The science of observing how things work, describing the organization of the universe, and finding the connections between cause and effect to understand natural laws.

Matter

Anything that has mass and takes up space.

Energy

A measure of the ability to make things change or a system's ability to change or create change in other systems.

Natural Law

A rule that tells how or why something happens the particular way it does, which all events in nature are believed to obey.

Experiment

A situation carefully set up under controlled conditions to observe what happens and investigate relationships between variables.

Analysis

The detailed thinking done to interpret and understand observations made during an experiment.

Mass

The measure of the amount of matter that makes up an object.

System

A group of objects, effects, and variables that are related and chosen for investigation.

Variable

A factor that affects the behavior of a system.

Macroscopic

Refers to observations, variables, or scales that are large enough to be directly seen or measured.

Atomic Scale

Refers to factors or variables on the scale of atoms and molecules, which are far too small to be directly observed.

Scientific Method

A systematic process used to conduct experiments, involving asking a question, formulating a hypothesis, testing it through procedure, collecting and analyzing data, and drawing conclusions.

Independent Variable

The variable that is changed by the experimenter in an experiment to cause a change in the system, plotted on the horizontal or $x$-axis.

Dependent Variable

The variable in an experiment that responds to or shows the effect of changes made to the independent variable, plotted on the vertical or $y$-axis.

Hypothesis

An educated guess that predicts the cause-and-effect relationship between the independent and dependent variables in an experiment.

Control Variable

A variable in an experiment that is intentionally kept constant so that only one experimental variable is tested at a time.

Experimental Variable

The single variable in an experiment that is intentionally changed.

Model

An explanation in physics that links the variables in a system through cause-and-effect relationships.

Measurement

A precise value that communicates an amount, consisting of both a numerical quantity and a specified unit.

Unit

A standardized metric or quantity used to specify and communicate measurement amounts.

Distance

The amount of space between two points, measured in units of length.

Metric System

The International System of Units based on powers of 10, using units of length such as millimeters, centimeters, meters, and kilometers.

English System

A system of standardized units for measuring distance commonly used in the United States, including inches, feet, yards, and miles.

Time Interval

A specific quantity of time that has both a beginning and an end, represented by the symbol $t$ in physics.

Second

The basic unit of time in both the English and metric systems, defined such that there are $86,400\,\text{seconds}$ in an average day of $24\,\text{hours}$.

Graph

A visual representation or picture that shows how two variables are related.

Speed

The distance traveled by an object divided by the time it took to travel that distance ($v = \frac{d}{t}$).

Forms of the Speed Equation

The three mathematical arrangements connecting speed ($v$), distance ($d$), and time ($t$): $v = \frac{d}{t}$, $d = vt$, and $t = \frac{d}{v}$.

Constant Speed

Motion in which an object travels the exact same distance during every second, keeping its speed unchanged.

Speed of Light

The ultimate speed limit in the universe, equal to $300,000,000\,\text{m/sec}$ ($3 \times 10^8\,\text{m/sec}$).

Velocity

A measurement that specifies both an object's speed and its direction of motion.

Serendipity

An event occurring by accident that results in an unexpected and positive scientific discovery.

Alexander Fleming

The British bacteriologist who serendipitously discovered penicillin in 1928 after observing mold spore growth on a Staphylococcus petri dish.

Penicillin notatum

The species of mold that produced a substance inhibiting the growth of Staphylococcus bacteria, named penicillin by Alexander Fleming.