Heat Transfer NOTES

Thermal Energy

•TOTAL energy of motion in molecules of

a substance

(therm=heat)

Temperature• Average amount of energy

in motion

* Measured with a thermometerThe longer the arrow the faster the movement

What is temperature?

• Average amount of thermal energy for each molecule of a substance

• Measured with a thermometer

• In degrees Celsius, Fahrenheit or Kelvin

How do thermometers work?

• The liquid in the bulb expands with heat and contracts with the lack of heat.

• Celsius is the scientific unit for measuring temperature because it is the most similar to the metric system.

Galileo Thermometer

• Galileo invented the first thermometer between 1500 and 1600.

• Uses glass spheres filled with colored alcohol.

• The spheres are designed to sink in sequence as the liquid inside is warmed and density increases.

Temperature points

  Freezing Boiling Human

Celsius 0 C 100 C 37 C

Fahrenheit 32 F 212 F 98.7 F

Kelvin 273 K 373 K 310 K

0 K - absolute zero no motion in a substance

Temperature Conversions

• Celsius to Fahrenheit• F = (C x 1.8) + 32

• Fahrenheit to Celsius • C = (F – 32) x .56

• Can you explain how to convert Celsius to Kelvin?

Temperature Conversion Practice

• 1. 75 °F = __________ °C

• 2. 0 °F = __________ °C

• 3. 98.6 °F = __________ °C

• 4. 160 °F = __________ °C

• 5. -10 °F = __________ °C

• 6. 45 °C = __________ °F

• 7. 30 °C = __________ °F

• 8. -10 °C = __________ °F

• 9. 200 °C = __________ °F

• 10. - 40 °C = __________ °F

Answers – Temperature Conversions

• 1. 75 °F = __23.9____ °C

• 2. 0 °F = __-17.8____ °C

• 3. 98.6 °F = _ 37_____ °C

• 4. 160 °F = __71.1____ °C

• 5. -10 °F = __-23.3___ °C

• 6. 45 °C = __113_____ °F

• 7. 30 °C = __86______ °F

• 8. -10 °C = ___14_____ °F

• 9. 200 °C = __392_____ °F

• 10. -40 °C = __-40_____ °F

HEAT Energy Transfers…

•from hotter object to

COOLER objectHeathot cold

Let’s try it: Rub your Hands together. Grab the legs of your chair. Can you feel the heat?

3 types of heat Transfer1) Radiation: • pure energy that moves through empty space• infrared (not visible) • felt as heat

2) Conduction:• transfer of heat by touch• Heat moves through a material without the material moving

itself

3) Convection: • transfer of heat by movement of fluid (liquid/gas)• Heat moves through a material by actually moving the

material itself

Radiation (infrared)• Examples:

*Feel warmth on face from sun=

solar radiation

* Warmth of a fire

* Heat off car engine

More examples of radiation

•Heated driveways/

sidewalks

* Heated floors

3 types of heat Transfer1) Radiation: • pure energy that moves through empty space• infrared (not visible) • felt as heat

2) Conduction:• transfer of heat by touch• Heat moves through a material without the material moving

itself

3) Convection: • transfer of heat by movement of fluid (liquid/gas)• Heat moves through a material by actually moving the

material itself

Conduction=touch• Examples:

* Hot sand on feet

* Touching hot light bulb• * Touching metal on hot seatbelt

* Stove to pan handle

* Melting ice in hand

3 types of heat Transfer1) Radiation: • pure energy that moves through empty space• infrared (not visible) • felt as heat

2) Conduction:• transfer of heat by touch• Heat moves through a material without the material moving

itself

3) Convection: • transfer of heat by movement of fluid (liquid/gas)• Heat moves through a material by actually moving the

material itself

Convection* Convection in water

* Convection oven

Can you identify each type of heat transfer?

1. A metal spoon is placed in a hot drink and the handle becomes warm.

2. Water at the bottom of a pot takes in heat from the stove burner and moves upwards taking the heat with it.

3. If you stand in front of a campfire, you can feel the heat but if you move away from the campfire you feel cold.

* Holiday chimes

* Spinning Lamps

LOOK AT ALL THREE:

Heat Transfer in the Troposphere

radiation

conduction

* convection

* CONVECTION is the most dominant heat transfer in the troposphere

EARTH

Atmosphere