Get the box of Stuff Wood, steel, aluminum, melamine

Properties of Materials Goal: Students will be able to describe various physical properties that materials have

Discussion differentiate between chemical and physical properties differentiate between chemical and physical properties At your tables list examples of chemical and physical properties. At your tables list examples of chemical and physical properties. I will call on each table and make a list of all the ones we can think of. I will call on each table and make a list of all the ones we can think of.

Chemical Properties how a material interacts with another material how a material interacts with another material “social” behavior “social” behavior response to other matter (or lack of response) response to other matter (or lack of response) reactions reactions

Chemical Properties Examples: Examples: burning burning reaction with acid reaction with acid reaction with water reaction with water corrosion/rusting/oxidation corrosion/rusting/oxidation others???? others????

Physical Properties characteristics it possesses by itself (in and of itself) characteristics it possesses by itself (in and of itself) “personal” traits “personal” traits response to energy response to energy

Physical Properties color color size size texture texture melting point melting point boiling point boiling point solubility solubility luster luster density density magnetism magnetism odor odor viscosity viscosity crystalline structure crystalline structure

Physical Properties Electrical properties Electrical properties conductor or insulator conductor or insulator Optical properties – response to light Optical properties – response to light index of refraction – bending of light index of refraction – bending of light transparent – light passes through transparent – light passes through translucent – some light passes through but no distinct image translucent – some light passes through but no distinct image opaque – no light passes through opaque – no light passes through

Physical Properties Thermal properties – response to heat Thermal properties – response to heat conductivity conductivity specific heat – how much energy it takes to change temperature specific heat – how much energy it takes to change temperature thermal expansion – example: iron wire demo thermal expansion – example: iron wire demo

Mechanical Properties subgroup of physical subgroup of physical response to force or stress response to force or stress force – a push or pull force – a push or pull stress – force causing a deformation or distortion (force per unit area) stress – force causing a deformation or distortion (force per unit area)

Mechanical Properties Examples workability workability malleability – can be flattened malleability – can be flattened ductility – can be drawn into wire (stretched), bent, or extruded ductility – can be drawn into wire (stretched), bent, or extruded

Mechanical Properties Examples brittleness brittleness breaks instead of deforming when stress is applied breaks instead of deforming when stress is applied hardness hardness resistance to denting or scratching resistance to denting or scratching

Mechanical Properties Examples elasticity elasticity ability to return to original shape after being deformed by stress ability to return to original shape after being deformed by stress rubber ball or piece of elastic rubber ball or piece of elastic plasticity plasticity retains new shape after being deformed by stress retains new shape after being deformed by stress wet clay ball or piece of saran wrap wet clay ball or piece of saran wrap

Some of the properties At your tables you will find some signs with different physical properties. At your tables you will find some signs with different physical properties. Go around between tables and answer the questions on a separate piece of paper. Go around between tables and answer the questions on a separate piece of paper.

Index of Refraction Question. What two materials here have a similar index of refraction? (the three materials are glass, HDPE, and mineral oil) Electrical conductivity What materials here are non-conductive electrically? (the materials are brass, copper coated steel, wax, glass and carbon fiber) Hardness Which material here is the hardest? (Pine and Melamine)

Mechanical Properties Examples toughness toughness ability to absorb energy ability to absorb energy resistance to fracture resistance to fracture strength strength resistance to distortion by stress or force resistance to distortion by stress or force several types: tensile, compressive, torsional, bending, shear several types: tensile, compressive, torsional, bending, shear

Types of Stresses/Forces Tension Tension pulling pulling examples: tug-of-war, slingshot examples: tug-of-war, slingshot Compression Compression pushing together or squeezing pushing together or squeezing examples: bed springs, can crusher, bench vise examples: bed springs, can crusher, bench vise

Types of Stresses/Forces Torsion Torsion twisting twisting example: wringing out a wet towel example: wringing out a wet towel Shear Shear opposite forces not lined up opposite forces not lined up examples: scissors, pin in a wagon tongue, shear pin examples: scissors, pin in a wagon tongue, shear pin

stress strain Ceramic or glass metal polymer straight line = elastic region curved line = plastic region

City of Materials

materials.eng.cam.ac.uk/mpsite/interactive_char ts/strength-ductility/IEChart.html materials.eng.cam.ac.uk/mpsite/interactive_char ts/strength-ductility/IEChart.html materials.eng.cam.ac.uk/mpsite/interactive_char ts/strength-ductility/IEChart.html materials.eng.cam.ac.uk/mpsite/interactive_char ts/strength-ductility/IEChart.html

General Classes of Materials

Polymers

Ceramics

Composites

Metals and Alloys

Wood and Wood Products

Free write On a piece of paper please describe various physical and chemical properties that material's have. If you can include how you could test those physical properties. On a piece of paper please describe various physical and chemical properties that material's have. If you can include how you could test those physical properties.

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Density

Density how much “stuff” per how much “space” how much “stuff” per how much “space” stuff = matter (mass) stuff = matter (mass) space = volume space = volume per = divide per = divide Density = Density = Unit = g/cm 3 or g/mL Unit = g/cm 3 or g/mL mass volume

Mass Mass amount of matter amount of matter measured with a balance measured with a balance unit = grams (g) unit = grams (g) Mass

Volume Volume Volume how much space it occupies how much space it occupies liquids liquids measured with a graduated cylinder measured with a graduated cylinder unit = mL unit = mL solids solids regular-shaped regular-shaped find the dimensions and use an equation find the dimensions and use an equation irregular-shaped irregular-shaped use the water displacement method use the water displacement method units = cm 3 units = cm 3 1cm 3 = 1 mL 1cm 3 = 1 mL

Variations in Density Density varies with change in temperature of a substance. Density varies with change in temperature of a substance. warmer is usually less dense warmer is usually less dense warm objects/substances usually expand warm objects/substances usually expand same mass, more volume same mass, more volume Density does not vary with a change in amount of a substance Density does not vary with a change in amount of a substance Which is more dense: Which is more dense: a gram of aluminum or a kilogram of aluminum? a gram of aluminum or a kilogram of aluminum?

Calculating Density of an Unknown Solid Procedure: You must do two cylinders, two cubes, and one irregular shaped solid. You must do two cylinders, two cubes, and one irregular shaped solid. Make a table to record all data. 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. Use the entire sample for the irregular shaped solid.

Calculating Density of an Unknown Solid 3. 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). Use the digital calipers and convert mm to cm (move decimal point one place to the left). cube: length, width, and height cube: length, width, and height cylinder: diameter and height cylinder: diameter and height 4. Use water displacement to find the volume of the irregular shaped solid Record it in your data table. Record it in your data table. Use the entire sample. Use the entire sample. Describe the basic procedure for water displacement in your journal. Describe the basic procedure for water displacement in your journal.

Calculating Density of an Unknown Solid 5. Calculate and record the volume for the regular shaped solids using the following formulas: cube: volume = length x width x height cube: volume = length x width x height cylinder: volume = πr 2 h cylinder: volume = πr 2 h radius = diameter/2 radius = diameter/2 π = 3.14 π = 3.14

Calculating Density of an Unknown Solid 6. Calculate and record the density of the five materials. Be sure to include units. Be sure to include units. Record the formula for density in your journal. Record the formula for density in your journal. 7. Use the list of densities to identify each material and record your choice.