Temperature, Heat & Thermal Equilibrium

THINK IT OVER

HEAT = TEMPERATURE?

MORE HEAT = MORE TEMPERATURE?

Heat - energy transfers from one object to another because of temperature difference

Temperature - measure of the average kinetic energy of the atoms and molecules in substance

BRAIN POWER

Temperature

Heat

Definition Measure of the degree of hotness

A form of energy

Characteristic

Determines the direction of heat flow

Transfer of energy from a region of higher temp. to another region of lower temp.

Classification

Base quantity Derived quantity

SI Unit Kelvin, K Joule, J

Other unit Celsius, oC Calorie, cal

Learning Outcomes

At the end of the lesson, students should be able to:

1) explain thermal equilibrium 2) explain how a liquid-in-glass

thermometer works.

How Does Thermal Equilibrium Achieve?

Mechanism of Thermal Equilibrium

AHOT

BCOLD

+

Faster rate of energy transfer from HOT to COLD

Slower rate of energy transfer from COLD to HOT

HOTHOT COLDCOLD

HOTHOT COLDCOLD

Energy transferred at the same rate between HOT and COLD

No NET HEAT transfered

A B

THERMAL EQUILIBRIUM :

Two object have same temperature

No net flow of heat between two

objects

1

2

Liquid-in-glass thermometerMercury Alcohol

Freezing point : -39oCBoiling point : 357oC

Freezing point : -115oCBoiling point : 78oC

It does not wet the tube

It wet the tube.

Opaque.Easy to read.

Colorless.It needs to be dyed.

Poisonous Safe liquid

Expensive Cheap

Conduct heat well, responds faster to temperature changes.

Responds more slowly than mercury.

Liquid-in-glass thermometer

Calibration ( Penentukuran )

Mercury is used because : Opaque (Legap)

- easy to take reading Expands ( mengembang) uniformly

with heat- uniform scale

High cohesive force ( daya lekitan tinggi )- not stick to glass wall

High Boiling point- measure high temperature

Improve sensitivity1.Narrow capillary tube

2.Thin glass wall bulb (bebuli)

3. Small bulb ( bebuli)

HOMEWORK

Read about specific heat capacity and write your own notes.

Ready for class after school break.

SELAMAT BerPHYSICS

Bye2