Properties of Materials
Free Writedifferentiate between chemical and physical properties
list examples of each
Chemical Propertieshow a material interacts with another material
social behavior
response to other matter (or lack of response)
reactions
Chemical PropertiesExamples:burningreaction with acidreaction with watercorrosion/rusting/oxidationothers????
Physical Propertiescharacteristics it possesses by itself (in and of itself)
personal traits
response to energy
Physical Propertiescolorsizetexturemelting pointboiling pointsolubilitylusterdensitymagnetismodorviscositycrystalline structure
Physical PropertiesElectrical propertiesconductor or insulator
Optical properties response to lightindex of refraction bending of lighttransparent light passes throughtranslucent some light passes through but no distinct imageopaque no light passes through
Physical PropertiesThermal properties response to heat
conductivity
specific heat how much energy it takes to change temperature
thermal expansion example: iron wire demo
Mechanical Propertiessubgroup of physical
response to force or stressforce a push or pull
stress force causing a deformation or distortion (force per unit area)
Mechanical PropertiesExamplesworkabilitymalleability can be flattenedductility can be drawn into wire (stretched), bent, or extruded
Mechanical PropertiesExamplesbrittlenessbreaks instead of deforming when stress is applied
hardnessresistance to denting or scratchinghttp://www.youtube.com/watch?v=i1x-vJ85sBA http://www.youtube.com/watch?v=eF5943tlbBs
Mechanical PropertiesExampleselasticityability to return to original shape after being deformed by stress rubber ball or piece of elastichttp://www.flixxy.com/golf-ball-slow-motion.htm
plasticityretains new shape after being deformed by stress wet clay ball or piece of saran wrap
Mechanical PropertiesExamplestoughnessability to absorb energy resistance to fracturehttp://www.steeluniversity.org/content/html/eng/charpy-test.asp http://www.youtube.com/watch?v=a_aOlh6dSA8http://www.youtube.com/watch?v=N276_xjl04g&feature=related
strengthresistance to distortion by stress or force several types: tensile, compressive, torsional, bending, shear
Types of Stresses/ForcesTensionpullingexamples: tug-of-war, slingshot
Compressionpushing together or squeezingexamples: bed springs, can crusher, bench vise
Types of Stresses/ForcesTorsiontwistingexample: wringing out a wet towel
Shearopposite forces not lined upexamples: scissors, pin in a wagon tongue, shear pin
Stress-Strain CurveStress cause force causing a deformation or distortion
Strain effectchange caused by stress (ex. elongation)
stressstrainCeramic orglassmetalpolymerstraight line = elastic regioncurved line = plastic region
City of Materialshttp://dev.sancsoft.com/educationasm/asmeducation.html http://www.cityofmaterials.com
Tensile testshttp://www.youtube.com/watch?v=SzJ4YLbMF-Y&NR=1 http://www.youtube.com/watch?v=W5A8gU37wGg&feature=relatedClose up of tensile strain and break
http://www.matsceng.ohio-state.edu/mse205/lectures/chapter6/index_chap6.htm http://ed1.eng.ohio-state.edu/Courses/EDT&L221/HTML%20Presentation%20folder/sld001.htm http://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/strength-ductility/IEChart.html
General Classes of Materials
Polymers
Ceramics
Composites
Metals and Alloys
Metals and Alloys
Wood and Wood Products
Density
Densityhow much stuff per how much spacestuff = matter (mass)space = volumeper = divide
Density =
Unit = g/cm3 or g/mL massvolume
MassMassamount of mattermeasured with a balanceunit = grams (g)
VolumeVolume how much space it occupiesliquidsmeasured with a graduated cylinderunit = mLsolidsregular-shapedfind the dimensions and use an equationirregular-shapeduse the water displacement methodunits = cm31cm3 = 1 mL
Variations in DensityDensity varies with change in temperature of a substance.warmer is usually less densewarm objects/substances usually expandsame mass, more volume
Density does not vary with a change in amount of a substanceWhich is more dense: a gram of aluminum or a kilogram of aluminum?
Calculating Density of an Unknown SolidProcedure:
You must do two cylinders, two cubes, and one irregular shaped solid.
Make a table to record all data.
1. Record the identifying letter of the sample.
2. Measure and record the mass.Use the entire sample for the irregular shaped solid.
Calculating Density of an Unknown Solid3. Measure and record the dimensions of the regular shaped solids.Use the digital calipers and convert mm to cm (move decimal point one place to the left). cube: length, width, and heightcylinder: diameter and height
4. Use water displacement to find the volume of the irregular shaped solidRecord it in your data table.Use the entire sample.Describe the basic procedure for water displacement in your journal.
Calculating Density of an Unknown Solid5. Calculate and record the volume for the regular shaped solids using the following formulas:
cube: volume = length x width x height
cylinder: volume = r2hradius = diameter/2 = 3.14
Calculating Density of an Unknown Solid6. Calculate and record the density of the five materials.Be sure to include units.Record the formula for density in your journal.
7. Use the list of densities to identify each material and record your choice.
Burning strike a match and burn a piece of paper burn a piece of magnesium burn a copper wireDrop a piece of zinc in HCl3. Show clip of sodium in water????http://cwx.prenhall.com/petrucci/medialib/media_portfolio/20.html - videosDemo viscosity tubesPyrite for luster1. Use a digital meter on a conductor and on an insulator2. Index of refraction how much light bends as it passes through a substance example: standing in waist deep water or a pencil in a beaker of water, remind students of water gel crystals we did at beginning of yearshow examples of all 3 use glass or plastic show a Corelle platehttp://webphysics.davidson.edu/faculty/dmb/EdibleOpticalMaterials/find_n_background.htmhttp://gr5.org/index_of_refraction/Conductivity have them touch a table leg (wood) and a chair leg (metal) at the same time discuss use Ed. In. melt blocksSpecific heat metals have low doesnt take much energy to heat them up or cool them down ceramics/glass are higher water is very high (reason it is used in cooling systems)Ball and ring, bimetallic strip, piston and sleeveMalleability - (show students a rolled penny)Ductility - (show drawn wire)Show Play doh fun factory for extrusionhttp://www.chem-pics.co.uk/animations.htm Brittleness snap a piece of chalkHardness - pass around talc (do a metal hardness test demo dent metal plates using a heavy weight w/ a ball bearing attached make a shading of the dents and measure their width w/ a caliper rank the metals)
Show happy/sad ballsShow poppers????(toss a metal piece - scoopula, plastic water bottle, unglazed dried clay (in a baggie), a test tube (in a baggie), Corelle plate) metals and polymers tend to exhibit more toughness than ceramics or glass Corelle is an exceptionhttp://www.wmtr.com/Content/charpy.htm Excellent simulation - http://www.steeluniversity.org/content/html/eng/charpy-test.asp Also use the 2 overheads(demo break a piece of chalk w/ torsion) Show GM video clips of testing methodsstress/strain stuff - OSU Properties of industrial materials PP - OSU3. Strength and elongation graphs - CambridgeClass levelPolymersceramicscompositesMetals and alloys Metals and alloysWood and wood products
