Physical Physical Properties of Properties of

MatterMatter Building a House Model-

Conductors And

InsulatorsTEKS 5.5A

5.55.5 The student knows that matter has measurable The student knows that matter has measurable physical properties and those properties determine physical properties and those properties determine

how matter is classified, changed, and used.how matter is classified, changed, and used.

The student is expected to . . . *A. classify matter based on physical properties including mass, magnetism, physical state (solid, liquid, and gas), relative density (sinking and floating), solubility in water, and the ability to conduct or insulate thermal energy, or electric energy

Heat EnergyHeat Energy• Heat moves from areas of high temperature

to areas of low temperature. • When two bodies of different temperatures

come into contact, they will exchange heat energy until the temperature of both is made the same.

• The amount of energy transferredtransferred is the amount of heat exchanged.

TemperatureTemperature• Temperature measures

the physical property of ‘how hot’ or ‘how cold’ material is

• Celsius is the common SI unit for temperature measurement. ° C

• Thermometers are the scientific tools used to measure temperature.

ConductorsConductors of Heat of Heat EnergyEnergy

• Materials that DO transfer heat energy from higher temperature to lower temperature areas.

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• Exampleso materials made of metal and glass

Conduction means allowing the transfer of heat from a higher temperature area to a lower temperature area.

Heat energy flow

InsulatorsInsulators of Heat Energy of Heat Energy• A material that does NOT transfer heat

readily

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• Exampleso materials made of rubber, wood, clotho materials that have air pockets

Insulation means providing a barrier to the flow of energy, in this case, heat.

Heat energy

Insulator

Heat Heat insulationinsulation is also called is also called thermal thermal insulationinsulation

The house insulation in the walls and attic will slow down the transfer of heat. In cold weather, inside a warm house will be warmer than the outside temperature. In hot weather, inside a cool house will be cooler than the outside temperature.

The blanket keeps body heat (heat energy) close to the boy. Heat energy is not transferred into the surrounding air.

The styrofoam cup slows down heat transfer. A cold drink in the cup will stay colder than the surrounding air. A hot drink in the cup will stay hotter than the surrounding air

.

Practice your learningPractice your learningConductors

• Describe conductors.

• Give an example of a conductor.

• Describe a practical use of a heat conductor.

Insulators

• Describe insulators.

• Give an example of an insulator.

• Describe a practical use of a heat insulator.

Heat Heat conductorsconductors and and insulatorsinsulators in in

the classroomthe classroomA classroom model

Students are building a model of a Students are building a model of a house using a cardboard box and house using a cardboard box and other common materials. They will other common materials. They will test the test the insulatinginsulating properties of properties of materials that could be used in the materials that could be used in the attic of the model. attic of the model.

1. Choose the 1. Choose the insulatinginsulating material to use in material to use in

the attic of the model that will keep the the attic of the model that will keep the

house the coolest.house the coolest.

A. Aluminum foil

D. Glass plate

C.Styrofoam

B. Metal screen

Correct: Styrofoam is a good insulator and will not conduct heat. The styrofoam will not allow much heat energy from the lamp to transfer to the attic.

C.Styrofoam

Incorrect choices:Metals, like aluminum and screens, and glass plates are poor heat insulators, but good heat conductors. These materials will allow the heat energy from lamp to transfer to the attic.

2. The primary heat energy source for the 2. The primary heat energy source for the

model house system ismodel house system is

A. the classroom window.

B. the lamp when lit.

C. the air in the room.

D. the outside temperature.

Correct: B, the lamp when litThe lamp when turned on and aimed at the roof of the model house supplies the heat energy.

Incorrect choices:A. Classroom window is probably too far from

model.

B. Room temperature air would not provide any additional heat to the model.

C. Since the model is constructed indoors, the outside temperature would not affect it.

3. Materials are considered heat 3. Materials are considered heat insulatorsinsulators

when theywhen they

A. change heat to light.

B. transfer heat energy easily.

C. make their own heat.

D. help block the transfer of heat.

Correct: D, when they block the transfer of heat Materials that are insulators do not let heat energy pass through them easily.

Incorrect choices:

A. Heat energy is not being changed to light.

B. Materials that are heat conductors let this form of energy pass through them easily.

C. Insulators are not the source of heat energy.

44. Which statement best describes the . Which statement best describes the

cardboard house model?cardboard house model?

A. The model is built to demonstrate electric conductors.

B. The model shows materials students should not use.

C. Melting of the model house is a safety problem.

D. In the natural world, solar energy would provide the heat.

Correct: D, the lamp is a representation of the Correct: D, the lamp is a representation of the

Sun and solar energySun and solar energy

Incorrect choices:

A. The purpose of building the model is to test materials for heat insulation not electricity conduction.

B. The materials are appropriate for student use.

C. If safety rules are not observed, burning, not melting, could be a problem.

5. Which attic material 5. Which attic material insulatedinsulated the model the model

house best?house best?

Attic materialstested

Thermometerreadings

Aluminum foil 35ºC

Metal screen 30ºC

Styrofoam 20ºC

Glass plates 25ºC

A thermometer placed on the roof reads 35º C.

A. Aluminum foil

B. Metal screen

C.Styrofoam

D.Glass plates

A second thermometer is placed inside the house.

Correct: C, styrofoamThe temperature readings with the thermometer placed inside the house indicated when styrofoam was used as insulation the temperature was 20ºC-the lowest recorded temperature. Materials that are insulators do not let heat energy pass through them easily.

Incorrect choices:All the other materials had recorded temperatures of higher

than 20º C. The best insulator should keep the inside of the

house the coolest (the lowest temperature). 20º was also

lower than the temperature of the heat from the lamp as

recorded with the roof thermometer.