1. P.1 Book 1 Section 1.2 Thermometers Galileo thermometer Thermometers Check-point 3 1.2Thermometers

2. P.2 Book 1 Section 1.2 Thermometers Galileo thermometer When temperature changes, the spheres rise or sink. The tag on the lowest floating sphere tells the temperature. 1.1 Galileo thermometer Video

3. P.3 Book 1 Section 1.2 Thermometers Thermometers liquid thread narrow glass tube liquid bulb T , liquid expands T , liquid contracts Length of the thread  temperature Commonly used: liquid-in-glass thermometer

4. P.4 Book 1 Section 1.2 Thermometers Thermometers Commonly used liquids: alcohol and mercury T > –115 °C T < 357 °C freezing point of alcohol boiling point of mercury Slow response Quick response Non-poisonous Poisonous Alcohol-in-glass Mercury-in-glass

5. P.5 Book 1 Section 1.2 Thermometers Thermometers Thermometer Temperature-dependent property Liquid-in-glass thermometer Volume of liquid Infra-red radiation Curvature of bimetallic strip Infra-red thermometer Rotary thermometer

6. P.6 Book 1 Section 1.2 Thermometers Thermometers Thermometer Temperature-dependent property Resistance thermometer Resistance of metal coil Thermistor thermometer Liquid crystal thermometer Colour of liquid crystal Resistance of thermistor

7. P.7 Book 1 Section 1.2 Thermometers Let’s begin Example 2 Calibrating a resistance thermometer Thermometers

8. P.8 Book 1 Section 1.2 Thermometers Resistance of the platinum wire: 100  in melting ice 139  in boiling water Example 2 Calibrating a resistance thermometer Platinum  resistance varies linearly with temperature  commonly used in resistance thermometers

9. P.9 Book 1 Section 1.2 Thermometers (a)What are the fixed points used in calibrating the thermometer? The ice point and the steam point. Example 2 Calibrating a resistance thermometer 100  in melting ice 139  in boiling water

10. P.10 Book 1 Section 1.2 Thermometers Example 2 Calibrating a resistance thermometer (b) When the resistance is 125 , what is the temperature? By proportion, temperature = 125 – 100 139 – 100  100 = 64.1  C 100  in melting ice 139  in boiling water

11. P.11 Book 1 Section 1.2 Thermometers (c)Describe the differences in particle motion in ice and hot water. The average K.E. of particles is higher in hot water The particles in hot water can move freely Example 2 Calibrating a resistance thermometer due to higher temperature. while those in ice can only vibrate.

12. P.12 Book 1 Section 1.2 Thermometers Check-point 3 – Q1 Match the thermometers to the appropriate temperature-dependent properties. Resistance thermometer Liquid-in-glass thermometer Thermistor thermometer Liquid crystal thermometer Colour of the liquid crystal Resistance of metal Volume of liquid Resistance of thermistor

13. P.13 Book 1 Section 1.2 Thermometers Check-point 3 – Q2 Which property does a rotary thermometer depend on to measure temperature? A Expansion of volume of liquid B Curvature of the bimetallic strip C Infra-red radiation released D Colour

14. P.14 Book 1 Section 1.2 Thermometers The End