1. 1.1 Temperature and thermometer
Galileo thermometer
Temperature
Temperature scale
Thermometers
Calibrating thermometers
Particle motion and temperature
Check-point 1 1 2 3 4 ? E 5
1.1 Temperature and thermometer

2. This is a Galileo thermometer.
Look at the lowest floating sphere. It tells us the temperature!
Video
1.1 Temperature and thermometer

3. Can I determine the temperature without using thermometer?
Galileo thermometer
Can I determine the temperature without using thermometer?
Is it good? Why?
1.1 Temperature and thermometer

4. 1 Temperature Temperature tells us how hot/cold a body is.
To measure and compare temperatures of different bodies accurately, we need...
temperature scale
thermometers
Temperature scale ~ ruler scale
1.1 Temperature and thermometer

5. 2 Temperature scale Choosing 2 readings of temperature,
T1: lower (ice) point (pure melting ice at normal atm pressure)
T2: upper (steam) point (steam over pure boiling water at normal atm pressure)
melting ice
boiling water
. . . divide n divisions . . .
. . .
1 division  degree
1.1 Temperature and thermometer

6. 2 Temperature scale Celsius scale Most commonly used temperature scale
Degree: C
Ice point  0 C, steam point  100 C
0 C
100 C
100 divisions
1.1 Temperature and thermometer

7. 3 Thermometers
With a temperature scale, temperatures can be measured accurately by thermometers.
bulb filament 2500 C
melting ice 0 C
boiling water 100 C C
surface of Sun 5000 C
Bunsen flame 1000 C
body 37 C
freezer –20 C
1.1 Temperature and thermometer

8. Each of them uses a property that changes with temperature.
3 Thermometers
There are many types of thermometers.
Each of them uses a property that changes with temperature.
1.1 Temperature and thermometer

9. a Liquid-in-glass thermometers
liquid thread
liquid bulb
narrow glass tube
T , liquid expands
T , liquid contracts
Length of the thread  temperature
1.1 Temperature and thermometer

10. a Liquid-in-glass thermometers
Alcohol-in-glass
Mercury-in-glass
T > –115 °C
T < 357 °C
freezing point of alcohol
boiling point of mercury
Slow response
Quick response
Non-poisonous
Poisonous
1.1 Temperature and thermometer

11. b Other thermometers Rotary thermometer (expansion of metals)
Thermistor thermometer (resistance)
Infra-red (IR) thermometer (emission of IR)
Liquid crystal thermometer (colour)
1.1 Temperature and thermometer

12. 4 Calibrating thermometers
Mark the liquid level
Mark the liquid level
Put in melting ice
Put in boiling water
1.1 Temperature and thermometer

13. 4 Calibrating thermometers
Simulations
1.1 Temperature and thermometer

14. 5 Particle motion and temperature
a Kinetic Theory
Theories explain/predict phenomena.
Kinetic theory
phenomena in heat
predicts
explains
1.1 Temperature and thermometer

15. There is attractive force between particles.
a Kinetic Theory E
All matters are made up of tiny particles which are constantly in motion.
There is attractive force between particles.
close particles
distant particles
weak attraction
strong attraction
e.g. in a gas...
1.1 Temperature and thermometer

16. a Kinetic theory Particles of... solid liquid gas
very close  strong attraction
less close  strong attraction
far apart  weak attraction
fixed positions; can vibrate only
irregular positions; can change position
irregular positions; can move freely at high speed
1.1 Temperature and thermometer

17. a Kinetic theory Simulation solid gas liquid fixed volume and shape
fixed volume but irregular shape
irregular volume and shape
Simulation
1.1 Temperature and thermometer

18. b Interpreting temperature by kinetic theory
Motion of the particles in a body depends on its temperature.
T 
 particles vibrate more rapidly/move faster
T 
 particles slow down
 temp. of a body  ave. KE of particles
Particles of bodies have the same ave. KE
 bodies have the same temp.
1.1 Temperature and thermometer

19. Check-point 1 1 Which of the following… Determine which of the…
4 When Karen puts a...
1.1 Temperature and thermometer

20. Which of the following about the Celsius scale is incorrect?
Check-point 1 – Q1
Which of the following about the Celsius scale is incorrect?
A Lower fixed point = 0 C Upper fixed point = 100 C
B (upper fixed point – lower fixed point)/100  each division is degree Celsius
C It is the only temp. scale available.
D T > 100 C and T < 0 C are OK.
1.1 Temperature and thermometer

21. Determine which of the following is different from the others.
Check-point 1 – Q2
Determine which of the following is different from the others.
A Clinical thermometers.
B Rotary thermometers.
C Alcohol-in-glass thermometers.
D Thermistor thermometers.
The resistance (not volume) of a thermistor changes with temp.
1.1 Temperature and thermometer

22. Which of the following is incorrect?
Check-point 1 – Q3 E
Which of the following is incorrect?
A Gas particles are far apart and move at very high speeds.
B Temp. rises  particles move faster
C Temp. is a measure of total KE
D Particles have same ave. KE  same temp.
1.1 Temperature and thermometer

23. ... in boiling water mercury column: 26.1 cm
Check-point 1 – Q4
... in boiling water mercury column: 26.1 cm
... under her tongue mercury column: 12.0 cm
… in melting ice
mercury column: ?? cm
1.1 Temperature and thermometer

24. Check-point 1 – Q4 100 C  26.1 cm, 37 C  12.0 cm
Let x be the length of mercury column in ice.
By proportion,
distance between 100 C and 37 C
100 – 37 =
distance between 100 C and 0 C
100 – 0
( ) – 12.0
( ) – ( ) = 63
100
26.1
26.1 x
x = 3.72 cm
1.1 Temperature and thermometer

25. The End
1.1 Temperature and thermometer

26. A mercury-in-glass thermometer
Example 1
A mercury-in-glass thermometer
An unmarked mercury-in-glass thermometer was put...
in melting ice, mercury column = 4.5 cm
in boiling water, mercury column = 22.0 cm
in warm water, mercury column = 11.5 cm
What is the temp. of warm water?
1.1 Temperature and thermometer

27. A mercury-in-glass thermometer
Example 1
A mercury-in-glass thermometer
In warm water, mercury column = 11.5 cm
Graphical method: plot a calibration graph
11.5
Warm water is 40 C.
1.1 Temperature and thermometer

28. Example 1 100 divisions between 4.5 cm & 22.0 cm By proportion,
A mercury-in-glass thermometer
in melting ice, mercury column = 4.5 cm in boiling water, mercury column = 22.0 cm in warm water, mercury column = 11.5 cm
100 divisions between 4.5 cm & 22.0 cm
By proportion,
11.5 – 4.5
Temp. of warm water =
 100
22.0 – 4.5
= 40 C
1.1 Temperature and thermometer

29. Return
1.1 Temperature and thermometer