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2.2,Physical Properties,There are pitchers of ice water and lemonade on a picnic table.How do you know which liquid is in each pitcher?Its easy!Lemonade is yellow and has a tart taste that is hard to miss.A yellow color and a tart taste are two properties of lemonade.,What are some examples of physical properties?,A,physical property,is any characteristic of a material that can be observed or measured without changing the composition of the substances in the material.,Examples of Physical Properties,Viscosity,conductivity,malleability,hardness,melting point,boiling point,and density are examples of physical properties.,Viscosity,The tendency of a liquid to keep from flowing is called its,viscosity,.,Thick liquids,such as corn syrup and honey,have a high viscosity.,Thin liquids,such as vinegar and water,have a low viscosity.,Examples of Physical Properties,Conductivity,A materials ability to allow heat to flow is called,conductivity.,Materials that have a high conductivity,such as metals,are called conductors.,Good conductors of heat are usually also good conductors of electricity.,Examples of Physical Properties,Malleability,The ability of a solid to be hammered without shattering is,malleability,.,Most metals,such as gold,are malleable.,An ice cube or piece of glass breaks into small pieces when struck with a hammer.Solids that shatter when struck are brittle,not malleable.,Examples of Physical Properties,Hardness,One material can scratch another material if it is harder than the other material.,A kitchen knife can scratch a copper sheet because stainless steel is harder than copper.,The material used to sharpen the knife blade must be harder than stainless steel.Diamond is the hardest known material.,Examples of Physical Properties,This Tlingit carver is using an adze to carve a canoe from Western red cedar.Red cedar is a relatively soft wood.The adze is hard.,Examples of Physical Properties,Melting and Boiling Points,The temperature at which a material changes state is a physical property.,The temperature at which a substance changes from solid to liquid(melts)is its,melting point.,The temperature at which a substance changes from liquid to gas(boils)is its,boiling point.,Examples of Physical Properties,Melting and Boiling Points,Which of these substances are liquids at room temperature(20,C,or 68,F)?,Answer:,Examples of Physical Properties,Melting and Boiling Points,Which of these substances are liquids at room temperature(20,C,or 68,F)?,Answer:octane,water,and acetic acid,Examples of Physical Properties,Density,The ratio of the mass of a substance to its volume is its density.,Density can be used to test the purity of a substance.,Silver has a density of 10.5 g/cm,3,.A coin with a density of 9.9 g/cm,3,is not made from silver,or it contains substances in addition to silver.,Examples of Physical Properties,How can knowing the physical properties of matter be useful?,Physical properties are used to identify a material,to choose a material for a specific purpose,or to separate the substances in a mixture.,Using Physical Properties,Using Properties to Identify Materials,A material can be identified by its properties.,Decide which properties to test.,Do tests on a sample of the unknown material.,Compare the results with the data reported for known materials.,Using Physical Properties,Using Properties to Choose Materials,Properties determine which materials are chosen for which uses.,For example,shoelaces must be flexible,that is they must be able to bend without breaking.,They must also be durable,that is,they must be able to withstand repeated use.,Using Physical Properties,Laces in hiking boots are usually made of nylon or leather,not from wood.,Using Physical Properties,What processes are used to separate mixtures?,Filtration and distillation are two common separation methods.,Using Properties to Separate Mixtures,Filtration,You can separate hot tea from loose tea leaves by pouring the mixture through a strainer.,Filtration,is a process that separates materials based on the size of their particles.,Using Properties to Separate Mixtures,These students filter(sift)dirt through a wire screen to locate small objects.Particles of dirt are small enough to pass through the holes,but objects such as broken bits of pottery are too large.,Using Properties to Separate Mixtures,Distillation,Sometimes all the particles in a solution are small enough to pass through a filter.,Distillation,is a process that separates the substances in a solution based on their boiling points.,Using Properties to Separate Mixtures,The change of water from a liquid to a gas during boiling is a physical change.A,physical change,occurs when some of the properties of a material change,but the substances in the material remain the same.,Recognizing Physical Changes,During a physical change,the size and shape of a material can change but not the composition.Some examples include,melting butter in a pan,crumpling a piece of paper,slicing a tom
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