Physical PropertiesSection 17.2

Demo• Describe the items you see displayed.– Color– Odor– Texture– Size– Shape – State

• Why is it important to use a variety of properties when describing objects?

Properties of Matter• Different forms of matter can be identified if

enough is known about their properties.• Properties are of two different types:

o Physical – properties that can be observed or measured without changing the matter’s identity

o Chemical – properties that describe matter’s ability to change into new matter that has different properties.

realplayer videos\Properties of matter - Bing Videos.flv

Physical Properties• There are many physical properties:

– State (solid, liquid, gas, plasma)

realplayer videos\STATES OF MATTER.flvrealplayer videos\Video pedia World - Physical Science Plasma.flv

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Physical Properties– Density: the amount of mass in a given

amount of space

Realplayer videos\HowStuffWorks Videos Density Videos video-37743.flv

Physical Properties– Malleability: the ability of a material to be

rolled or pounded into thin sheets, to be deformed without breaking when struck.

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Physical Properties– Ductility: the ability of a material to be drawn

out into a wire

Physical Properties– Solubility: the ability of a

material to dissolve in another substance, such as sugar in water

realplayer videos\Dissolving Styrofoam with Acetone.flv

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Physical Properties– Electric conductance: the

ability of a material to allow an electric current to pass through it

– Magnetism: some substances are attracted to a magnet

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Physical Properties– Sensory stimuli:

• color

• smell

• taste (halite)

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Physical Properties– Thermal conductivity: how fast a substance

transfers heat

realplayer videos\Video pedia World - Heat and States of Matter Thermal Conductance.flv

Physical Properties - Applications• Electronic coin testers in vending

machines can instantly identify the properties of real coins and reject fake coins.

– Electric current measures metal content and size

– Magnet and light sensors detect coin’s size and sort coins according to their value

– Coins without the correct metal content or size are rejected

Physical Properties - Applications• By comparing the density of King

Hieron II’s crown with that of a bar of pure gold, the Greek inventor and mathematician Archimedes was able to prove that the crown was not made of pure gold and that a goldsmith had cheated the king.

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library.thinkquest.org mysciencearticles.com

Ident. by Density• Each substance has its

own density, different from any other substance, which doesn’t change if the temperature and pressure stay the same. That means substances can be identified by their densities.

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Density of Liquids• Some liquids are more dense than others.

• Liquids that are more dense will sink, while less dense liquids rise.

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realplayer videos\7 Layer Density - Cool Science Experiment.flv

Cool Fact• The density of a fresh egg

is 1.2 g/mL, but the density of a spoiled egg is about 0.9 g/mL.

• The egg’s density decreases as it ages because as it spoils, it loses water through the tiny pores in the shell.

• So, don’t eat an egg that floats. It’s spoiled!

Physical Changes• Physical changes affect one or more of a

substance’s physical properties.• When matter undergoes a physical

change, no new substance is formed. The appearance of the matter may change drastically, but most of the identifying properties remain unchanged.

realplayer videos\Physical Changes2.flv

Physical Changes• Physical changes are reversible.• Freezing, melting, boiling, condensation,

evaporation and sublimation are all physical changes called changes of state.

• When sugar dissolves in water, a physical change has occurred. Evaporation can allow the sugar to be reclaimed.

realplayer videos\Physical Changes sugar in water.flv

Physical Changes• Although density is

the same for a substance at constant temperature and pressure, if the temperature and/or the pressure is changed, the density of the substance also changes.

References:• http://chemistry.about.com/od/lecturenotesl3/a/statesmatter.htm• http://jewelrynetwork.myshopify.com/pages/forging• http://www.substech.com/dokuwiki/doku.php?id=fracture_toughness• http://www.tutorvista.com/topic/sugar-dissolves-in-water-chemical-change• http://www.dorlingkindersley-uk.co.uk/nf/ClipArt/Image/0,,239027_1584561_,00.html• http://www.mii.org/Minerals/photosalt.html• http://chestofbooks.com/travel/italy/sicily/John-Stoddard-Lectures/Sicily-Part-28.html• http://library.thinkquest.org/25672/archimed.htm• http://mysciencearticles.com/page/9/• http://www.stevespanglerscience.com/experiment/density-tower-magic-with-science• http://roushnholding.com/twy/rw-density-chart.htm• http://www.nyu.edu/pages/mathmol/textbook/density2.html• http://www.bestanimations.com/Nature/Water/Water2.html• http://www.animationlibrary.com/animation/31062/Car_crashed/• https://www.brisbanehotairballooning.com.au/faqs/school/105-how-hot-air-balloons-fly.html• http://www.lytron.de/tools-technical/notes/fluessigkeitskuehlsysteme-fuer-flugzeuge.aspx