In this segment, we continue with our exploration of physical properties, including brittleness and malleability. We also learn about phase changes and observe a demonstration on the freezing point of water.
Students discuss their results of the unknown substance in the crushing experiement. Host defines Brittleness and Malleability. Teacher defines Physical Change. Host describes Phase Change and defines Enthalpy. Teacher explains Vaporization and Condensation. Host conducts an experiement on the Freezing Point of water. Students discuss Temperature. Host talks about Intermolecular Forces.
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.
Energy and Matter
Flows, cycles, and conservation. Tracking fluxes of energy and matter into, out of, and within systems helps one understand the systems’ possibilities and limitations.
Scale, Proportion, and Quantity
In considering phenomena, it is critical to recognize what is relevant at different measures of size, time, and energy and to recognize how changes in scale, proportion, or quantity affect a system’s structure or performance.
Stability and Change
For natural and built systems alike, conditions of stability and determinants of rates of change or evolution of a system are critical elements of study.
Science & Engineering Practices
Obtaining, Evaluating and Communicating Information
Any education in science and engineering needs to develop students’ ability to read and produce domain-specific text. As such, every science or engineering lesson is in part a language lesson, particularly reading and producing the genres of texts that are intrinsic to science and engineering. (NRC Framework, 2012, p. 76)
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.
SC3Obtain, evaluate, and communicate information about how the Law of Conservation of Matter is used to determine chemical composition in compounds and chemical reactions.
SC3.bPlan and carry out investigations to determine that a new chemical has formed by identifying indicators of a chemical reaction (specifically precipitate formation, gas evolution, color change, water production, and changes in energy to the system should be investigated).
SPS7Obtain, evaluate, and communicate information to explain transformations and flow of energy within a system.
SPS7.dAnalyze and interpret data to explain the flow of energy during phase changes using heating/cooling curves.
S8P1Obtain, evaluate, and communicate information about the structure and properties of matter.
S8P1.bDevelop and use models to describe the movement of particles in solids, liquids, gases, and plasma states when thermal energy is added or removed.
S8P1.dConstruct an argument to support the claim that when a change occurs it is either chemical or physical.
(Clarification statement: Evidence could include ability to separate mixtures, development of a gas, formation of a precipitate, change in energy, color, and/or form.)
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