heat transfer: conduction dunman secondary school science (physics)

HEAT TRANSFER: CONDUCTION

DUNMAN SECONDARY SCHOOLScience (Physics)

Some Expectations

Respect Others Respect the School Humility

Work Ethic

DO participate and ask questions. For order in class, raise your hand when asking a question.

BRING all specified books. HAND IN all homework ON TIME! Failure to

do so may result in consequences… (“Drink coffee” with Mr. Chew after school)

SHOW CARE and concern for each other. Help one another in homework. BUT NO COPYING OF ENTIRE ASSIGNMENTS!

Why learn heat transfer?

Many applications in real life.

Example: Making of engines, refrigerators, air cooling systems…

SOLDIER OF TOMORROW

Soldier suits can regulate temperature!!

HEAT TRANSFER

CONDUCTION CONVECTION RADIATION

How do you place a piece of paper over a candle flame without the

paper catching fire?

CONDUCTION

Conduction is the transfer of thermal energy without any flow of the material medium.

This is the main process by which thermal energy is transferred from one of the solid to another.

Free Electron Diffusion

Molecular Vibration

CONDUCTION

can occur by

Molecular Vibration

Demonstration of molecular vibration. What do you observe about the rate of

transfer? A slow process…

Test Your Understanding

Why are gases and liquids generally poor conductors of heat?

http://www.cartoonclipart.com/pages/girlread.html

Insulators and Conductors

Poor conductors are also called insulators.

Some examples: Water, Wood, Polystyrene.

Free Electron Transfer

METALS contain many free electrons. See Demostration Rate of heat transfer is now faster. Why?

Free Electron Diffusion

When heated, the free electrons move faster and diffuse to into the cooler parts of the metal.

Kinetic energy is then transferred to the molecules by collision.

Test Your Understanding

Why is copper a better conductor of heat than wood?

Your research

What are some applications of: Conductors Insulators

in everyday life? (Choose one) Do in groups of two or three.

Your Research

Presentation format – YOU DECIDE Concept Maps with Pictures? Short video? (Takes a long time… but if you

can… why not?) Research Paper?? (you sure???)

The point is: BE INNOVATIVE Dateline: 20 Mar 2006 (Mon) 1300 hrs

What we have learnt…

The main process by which thermal energy is transferred from one end of a solid to another is conduction.

Two mechanisms of conduction: Molecular vibration Free electron diffusion

Done by: Chew Yiming Clement