# Heat transfer I Can statements.

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Heat transfer I Can statements

A.1. I can explain the difference between heat and temperature.
Heat measures the total amount of movement in the molecules of an object/substance. Temperature measures the average movement of the molecules.

A.2. I can explain why most substances expand when heated and contract when cooled.
Most substances expand when heated because the molecules move faster, hit each other harder, and so rebound and create more space between them. Most substances contract when cooled because the molecules move slower, hit more gently, and therefore have less space between them.

A.3. I can give examples how expansion and contraction are taken into account during construction.
When building bridges, roads, and railroad tracks there are expansion joints included to account for the expansion and contraction of the materials during hot and cold periods.

A.4. I can describe the direction of heat movement between hot and cold objects and what occurs during equilibrium. A4. Heat always moves from hot to cold. At equilibrium, the molecules still hit each other and trade energy but stay at the same temp.

B.5. I can define and give examples of conduction.
Conduction is heat transfer by direct contact or by one molecule bumping into another in a solid. Examples: Heat a pan on a stove coil. Electricity running through a wire, friction (mechanical), hot spoon in a cup of hot liquid.

B.6. I can define and give examples of convection.
Convection is heat transfer in liquids and gases through currents. The warmer liquid/gas becomes less dense as it expands and so it rises. The cooler gas/liquid molecules are denser and so they sink. Examples: wind, boiling water, molten rock (mantle and lava), convection ovens, steam.

B.7. I can define and give examples of radiation.
Radiation is how heat moves through electromagnetic waves. Examples: infrared waves from a light bulb, a fire, sunlight, microwaves, etc.

B.8. I can give 3 factors that determine an object’s temperature increase by radiation
The 3 factors that determine the temp. increase of an object are: a) the intensity of the light b) the length of time the light shines on the object c) the amount of light absorbed.

B.9. and b.10. I can define and give examples of thermal and electrical conductors and insulators.
Conductors are materials that allow heat to move easily. They tend to gain and lose heat quickly. Ex. Metals (silver, copper, aluminum, iron). Metals have a high melting pt. Insulators are materials that do not allow heat energy to move easily. They tend to lose and gain heat slowly. Ex. Styrofoam, plastics, double pane windows that have a vacuum inside them.

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