Physical Science Vocabulary Glossary

Vocabulary flashcards created from Unit 1 (Introduction to Physical Science) and Unit 2 (Matter & Properties) glossaries.

Accuracy

how close a measurement, result, or statement is to the true or real value; i.e. how close a dart is to the bullseye

Dependent Variable (DV)

The variable that is not changed by the experimenter but is observed for changes due to changes made to the independent variable (IV)

Grams

base unit of mass used in the metric system

Independent Variable (IV)

The variable that is intentionally changed by the experimenter to determine if there is an effect on the dependent variable

Inference

Conclusion drawn based upon qualitative/quantitative observations and prior knowledge

Liters

base unit of volume used in the metric system

Meters

base unit of length used in the metric system

Observation

Using senses and measurement tools to collect qualitative and quantitative data

Precision

how close repeated measurements are to each other (not necessarily close to the true value); i.e. darts in a close grouping, but not necessarily close to the target

Qualitative Observations

Observations that are descriptive in nature and do not include numerical measurements (i.e. color, scent)

Quantitative Observations

Observations that are numerical in nature which involve measurements and data (i.e. height, mass)

Scientific Law

statements, based on repeated experiments or observations, that describe or predict a range of natural events

Scientific Method

The cyclical process in which experiments are conducted

Scientific notation

short way to write very long or very short numbers, format is $a \times 10^n$

Scientific Theory

Explanation of natural phenomena supported with a wealth experimental data

Absolute Zero

0 K or -273.15 C, lowest possible temperature where all particles stop moving

Chemical property

characteristic of substance that can only be observed or measured when it undergoes a change to become an entirely new substance substance

Compounds

pure substances made of two or more elements chemically combined in fixed ratio, ex: salt NaCl

Condensation

phase change from gas to liquid, exothermic/releasing heat

Conduction

transfer of heat energy by collisions between particles, ex. Spoon heating up in hot soup

Convection

transfer of heat in a fluid (liquid or gas) where heated particles move to new locations carrying the heat with them, ex. Boiling water or air currents

Density

measure of how heavy an object or substance is for its size, $D = \frac{m}{v}$

Elements

simplest pure substance made of only one type of atom; cannot be broken down further, ex: Gold (Au)

Endothermic

heat is gained by system, energy flowing into system causing surroundings to feel cold

Evaporation

phase change from liquid to gas, endothermic/absorbing heat

Exothermic

heat is released by system, energy flowing out of the system causing surroundings to feel hot

First Law of Thermodynamics

energy is conserved, can be changed from one form to another but can never be created or destroyed

Freezing

phase change from liquid to gas, exothermic/releasing heat

Gas

matter with no fixed shape and no fixed volume, expands to fill container

Heat

H, thermal energy transferred from one substance to another due to temperature differences, transferred from warmer substance to cooler one

Heterogeneous Mixture

mixture without a uniform composition and where different parts remain distinct, ex: sand and water or oil and water

Homogeneous Mixture

mixture with a uniform composition and appearance throughout, also called solutions, ex: saltwater or air

Kelvin

base unit of temperature in International system of units

Liquid

matter with fixed volume but takes shape of its container

Mass

measurement of the amount of matter in a given object

Melting

phase change from solid to liquid, endothermic/absorbing heat

Mixtures

contains two or more substances that are physically combined not chemically bonded

Physical property

characteristic of substance that can be observed or measured without changing the chemical composition of the substance

Plasma

matter where parts of atoms fly apart, gas of ions and electrons

Pure substance

matter with a definite composition and distinct properties

Radiation

energy sent out through electromagnetic waves that convert to heat when absorbed by a substance, ex. Heat from the sun, or fireplace

Second Law of Thermodynamics

heat flows only from hotter object to cooler object

Solid

matter with a fixed shape and volume

Surroundings

everything else (compared to system)

System

substance undergoing change

Temperature

T, measure of the hotness of an object, related to average kinetic energy per molecule of object; measured in Celsius or Kelvin, high temp = high kinetic energy

Thermal Energy

EH, total kinetic energy of all atoms and molecules in a substance; depends on amount of matter (volume/energy)

Volume

measurement of three-dimensional space an object occupies or a container encloses