1. DRILL April 23, 2009 Answer the following in your notebook:
U3h – L3
April 23, 2009
DRILL
Answer the following in your notebook:
What is a more scientifically correct way of saying “the ice cubes made my water cold”?
Identify the methods of heat transfer expressed in the pictures/diagrams below:
Radiation
Conduction
Convection

2. (Fluid and Thermal Technology)
U3h – L3
TEST FRIDAY – Unit 3F and Unit 3G
(Fluid and Thermal Technology)

3. Difference in Temperature
U3h – L3
HEAT TRANSFER
Thermal energy always travels from a region of higher temperature to a region of lower temperature.
Therefore, the driving force for heat transfer is
Difference in Temperature
Three methods of heat transfer:
Conduction
Convection
Radiation

4. HEAT TRANSFER Conduction Conduction happens through solids.
U3h – L3
HEAT TRANSFER
Conduction
The transfer of heat through a substance by collision of molecules.
Conduction happens through solids.
Metals are usually best conductors.
Free electrons greatly aid in the transfer of thermal energy.
Fluids are less conductive of heat due to larger distances between atoms.

5. U3h – L3
HEAT TRANSFER
Conduction

6. HEAT TRANSFER Convection Natural Convection
U3h – L3
HEAT TRANSFER
Convection
The transfer of heat by movement of a fluid.
Natural Convection
Fluid surrounding a heat source receives heat and rises (due to lower density)
Surrounding cooler fluid moves in to replace it.
Cooler fluid is heated, rises, and cycle continues.

7. HEAT TRANSFER Convection Forced Convection
U3h – L
HEAT TRANSFER
Convection
Forced Convection
Fans or other means are used to propel a fluid.
An convection current is induced.
Car engine and A/C are examples

8. HEAT TRANSFER Radiation
U3h – L3
HEAT TRANSFER
Radiation
The transfer of heat by electromagnetic waves
All objects, hot or cold, emit heat by radiation
No medium is necessary – radiation works in a perfect vacuum (the sun’s heat through space)
Light contains heat radiation
The visible spectrum carries less heat than the infrared spectrum

9. U3h – L3
HEAT TRANSFER
Radiation

10. Heat Transfer Game Warm water rises in a lake. Cold water descends.
U3h – L3
Heat Transfer Game
Is it Conduction, Convection, or Radiation?
Warm water rises in a lake. Cold water descends.
The sun transfers its heat to our planet through space.
A thermometer under your tongue shows that you have a high fever.
On cloudless nights, heat escapes from our planet and goes into space.
Convection
Radiation
Conduction
Radiation

11. U3h – L3
Heat Transfer Game
You place a spoon into a cup of cocoa and it gets hot over time.
A thermos bottle has a shiny interior. What type of heat transfer does it prevent?
Heat in the room moves with the warm currents from warmer areas to cooler areas.
Brownies bake in a glass pan using these 2 methods.
You feel the heat of a wood stove when you stand next to it.
Conduction
Radiation
Convection
Radiation (from oven) and Conduction (through pan)
Radiation and Convection

12. U3h – L3
CLASSWORK/HOMEWORK
With ONE partner, complete the Fluid and Thermal Technology Test Review sheet.
What you don’t finish in class, you must finish for homework.
LETTER all answers.