3 Thermal Physics

Question 1

State the distinguishing properties of solids, liquids and gases; relate them to the forces and distances between the molecules and to the motion of the molecules - the arrangement, separation, and motion of the molecules

Answer 1

Solids: fixed shape and volume; particles vibrate about fixed positions
Liquids: fixed volume but no fixed shape; particles vibrate, but can change positions
Gases: no fixed volume or shape; particles move about freely

Question 2

Describe qualitatively the pressure of a gas and the temperature of a gas, liquid or solid in terms of the motion of its particles

Answer 2

Gas - the motion of its molecules and their colliding with the walls creating a force
Liquid -
Solid -

Question 3

Brownian motion and the kinetic molecular model of matter

Answer 3

The random path of particles due to collisions with other particles

Question 4

Describe the use of thermometers to measure temperature on the Celsius scale

Question 5

Describe melting and boiling in terms of …

Answer 5

energy input without a change in temperature

Question 6

State the meaning of melting point

Question 7

State the meaning of boiling point

Question 8

Recall the melting and boiling points for water

Answer 8

0ᵒC, 100ᵒC

Question 9

Distinguish between boiling and evaporation

Answer 9

Evaporation - the escape of more-energetic molecules from the surface of a liquid
Boiling -

Question 10

Describe condensation and solidification

Question 11

Explain evaporation in terms of the escape of
more-energetic molecules from the surface of a
liquid

Question 12

Relate evaporation to …

Answer 12

the consequent cooling of the liquid

Question 13

3 factors that affect the rate of evaporation

Answer 13

temperature, surface area and draught over the surface

Question 14

Describe qualitatively, in terms of molecules, the effect on the pressure of a gas of a change of temperature at constant volume

Question 15

Describe qualitatively, in terms of molecules, the effect on the pressure of a gas of a change of temperature at constant volume

Question 16

Describe qualitatively, in terms of molecules, the effect on the pressure of a gas of a change of volume at constant temperature

Question 17

Describe qualitatively the thermal expansion of solids, liquids and gases at constant pressure; explain in terms of the motion and arrangement of molecules, the relative order of the magnitude of the expansion of solids, liquids and gases

Question 18

Describe how a physical property that varies with temperature may be used for the measurement of temperature, and state examples of such properties

Question 19

Understand the terms sensitivity, range and linearity in measuring temperature; describe and explain how the structure of a liquid-in-glass thermometer relates to its sensitivity, range and linearity

Question 20

Describe the structure of a thermocouple and show understanding of its use as a thermometer for measuring high temperatures and those that vary rapidly

Question 21

Recognise the need for and identify fixed points when measuring temperature

Question 22

Describe and explain the structure and action of liquid-in-glass thermometers

Question 23

Recognise and name typical good and bad thermal conductors

Question 24

Explain conduction in solids in terms of …

Answer 24

molecular vibrations and transfer by electrons

Question 25

Convection is the main method of energy transfer in …

Answer 25

fluids

Question 26

Relate convection in fluids to density changes

Question 27

Radiation is the method of ______ transfer that doesn’t require a ______ to travel through

Answer 27

energy, medium

Question 27

Radiation is the method of ______ transfer that doesn’t require a ______ to travel through

Answer 27

energy, medium

Question 28

Infrared radiation is the part of the _____________ ________ often involved in ______ transfer by _________

Answer 28

electromagnetic spectrum, energy, radiation

Question 29

Most effective surface colour and texture for radiation

Answer 29

Black, dull or matt

Question 30

Least effective surface colour and texture for radiation

Answer 30

White or silver, shiny

Question 31

Identify and explain some of the everyday applications and consequences of conduction, convection and radiation