CHAPTER 4
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
A form of energy
degree of hotness
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
A
HOT
Faster rate of
energy
transfer from
HOT to COLD
+
B
COLD
Slower rate
of energy
transfer from
COLD to HOT
HOT
COLD
HOT
COLD
Energy transferred at the same
rate between HOT and COLD
A
B
No NET HEAT transfered
THERMAL EQUILIBRIUM :
1
2
Two object have same temperature
No net flow of heat between two objects
Liquid-in-glass thermometer
Mercury
Freezing point : -39oC
Boiling point : 357oC
Alcohol
Freezing point : -115oC
Boiling point : 78oC
It does not wet the tube
Opaque.
Easy to read.
Poisonous
Expensive
Conduct heat well,
responds faster to
temperature changes.
It wet the tube.
Colorless.
It needs to be dyed.
Safe liquid
Cheap
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 sensitivity
1. 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