Defining the system under study—specifying its boundaries and making explicit a model of that system—provides tools for understanding and testing ideas that are applicable throughout science and engineering.
Science & Engineering Practices
Asking Questions and Defining Problems
Students at any grade level should be able to ask questions of each other about the texts they read, the features of the phenomena they observe, and the conclusions they draw from their models or scientific investigations. For engineering, they should ask questions to define the problem to be solved and to elicit ideas that lead to the constraints and specifications for its solution. (NRC Framework 2012, p. 56)
alloy - a homogeneous mixture of metals, or a mixture of a metal and a non-metal in which the metal is the major component.
brittleness - a material's ability to absorb energy before fracturing.
chemical change - any change that results in the formation of a new chemical substance.
chemical property - a characteristic of a substance that's observed during a chemical reaction.
chromatography - parts of a mixture are separated based on the ability of each dissolved component to travel through materials at different speeds.
combustibility - occurs when a material catches fire at a temperature above 43 degrees celcius.
compound - any substance formed from two or more elements that have been joined together chemically.
condensation - the phase change that occurs when water vapor cools down to form liquid water.
condensation point - the temperature at which a gas turns into a liquid at standard pressure.
crystallization - the separation of a pure solid substance from a solution containing the dissolved substance.
density - the amount of mass per unit volume.
deposition - when a gas changes directly into a solid without going through the liquid phase.
distillation - the process that separates homogenous mixtures based on the different boiling points of the substances.
enthalpy - the amount of heat in a system at constant pressure.
evaporation - occurs on the surface of a liquid as it changes into a gas.
filtration - a physical process used to separate solids from liquids by passing them through a barrier.
flammability - occurs when a material catches fire at a temperature below 43 degrees celcius.
freezing - when a liquid turns into a solid.
freezing point - the temperature at which a liquid turns into a solid.
heterogeneous mixture - a combination of two or more substances in which the original substances are separated into physical distinct regions.
homogeneous mixture - a combination of two or more substances that have uniform composition and chemical properties throughout; also known as a solution.
intermolecular force - any force that can hold or repel particles.
malleability - how readily a material's shape can be changed.
matter - anything that has mass and takes up space.
melting - when a solid turns into a liquid.
melting point - the temperature at which a solid turns into a liquid.
mixture - a combination of two or more pure substances in which each pure substance retains its individual chemical properties.
phase change - a special type of physical change in which a substance transitions among the states of matter, solid, liquid, and gas, but the chemical properties of the substance remain the same.
physical change - a change which alters a substance without altering its composition.
physical property - a characteristic that can be observed or measured without changing the chemical makeup of a substance. Types include color, odor, texture, boiling point, melting point, and density.
reactivity - the relative ability of a substance to undergo a chemical reaction.
solution - a combination of two or more substances that have uniform composition and chemical properties throughout; also known as a homogeneous mixture.
sublimation - when a solid transistions into a gas without going through the liquid phase.
temperature - a measure of the random kinetic energy in a sample of matter.
vaporization - the phase change from liquid to gas.
Georgia Standards of Excellence
SC2Obtain, evaluate, and communicate information about the chemical and physical properties of matter resulting from the ability of atoms to form bonds.
SC2.aPlan and carry out an investigation to gather evidence to compare the physical and chemical properties at the macroscopic scale to infer the strength of intermolecular and intramolecular forces.
SC2.bConstruct an argument by applying principles of inter- and intra- molecular forces to identify substances based on chemical and physical properties.
S8P1Obtain, evaluate, and communicate information about the structure and properties of matter.
S8P1.aDevelop and use a model to compare and contrast pure substances (elements and compounds) and mixtures.
(Clarification statement: Include heterogeneous and homogeneous mixtures. Types of bonds and compounds will be addressed in high school physical science.)
Request Teacher Toolkit
The Chemistry Matters teacher toolkit provides instructions and answer keys for labs, experiments, and assignments for all 12 units of study. GPB offers the teacher toolkit at no cost to Georgia educators. Complete and submit this form to request the teacher toolkit. You only need to submit this form one time to get materials for all 12 units of study.