Thermal Physics

Question 1

Properties of solid

Answer 1

• Closely packed
• Particles held in place
• Particles vibrate in place within the structure

Question 2

Properties of liquids

Answer 2

• Slightly packed together
• Particles able to move past each other
• Particles slide over each other in random motion

Question 3

Properties of gases

Answer 3

• Particles widely spaced
• Particles able to move freely
• Particles have random and faster movement

Question 4

Temperature of a gas

Answer 4

• When temperature increases the average kinetic energy of particles increase
• More forceful and frequent collision between particles and walls –> increase pressure

Question 5

Temperature of liquid

Answer 5

• Temperature increase –> increase kinetic energy
• Particles overcome some intermolecular force –> expansion and decrease in density

Question 6

Temperature of a solid

Answer 6

• Temperature increase –> vibration energy increases
• Spacing between molecules increase –> thermal expansion

Question 7

Brownian motion

Answer 7

Small particles (e.g. smoke) moving randomly due to constant collision with other fast-moving particles

Question 8

Melting

Answer 8

-The solid absorbs heat energy to overcome the intermolecular forces
-The absorbed energy is used to break the bonds between solid particles

Question 9

Boiling

Answer 9

-The liquid absorbs heat energy to overcome the intermolecular forces
-The absorbed energy is used to break the bonds between liquid particles

Question 10

What is a melting point

Answer 10

The temperature at which is changes from solid to liquid
e.g. water = 0 C

Question 11

What is a boiling point

Answer 11

The temperature temperature at which changes from liquid to gas
e.g. water 1 C

Question 12

Distinguish boiling and evaporation

Answer 12

Evaporation: Lose molecules from surface that has the highest energy at any temperature

Boiling: Happens at boiling point because molecules have enough energy to leave

Question 13

What is condensation

Answer 13

Gas to liquid

Question 14

What is solidification

Answer 14

Liquid to solid

Question 15

Pressure and temperature change

Answer 15

High temperature - Increase in pressure

Question 16

Pressure and volume change

Answer 16

Low volume - Increase in pressure

Question 17

Solid thermal expansion

Answer 17

• Atoms vibrate more
• Atoms move slightly further apart and expands a little in all directions

Question 18

Liquid thermal expansion

Answer 18

• Atoms vibrate more as they move around
• Molecules are spaced further apart due to smaller forces
• volume increases

Question 19

Gas thermal expansion

Answer 19

• Increase in volume much more then liquid and solids

Question 20

What is sensitivity

Answer 20

The amount of change in thermometric property for a unit change in temperature

Question 21

What is range

Answer 21

The maximum and minimum temperature

Question 22

What is linearity

Answer 22

Same change of physical property for same change of temperature

Question 23

Name good conductors

Answer 23

Silver, gold, copper, aluminium, steel, iron, seawater

Question 24

Name bad conductors

Answer 24

Glass, plastic, rubber, air, wood

Question 25

what is conduction

Answer 25

The transfer of heat energy or an electric charge through a material

Question 26

Explain the conduction process

Answer 26

-When heated atoms vibrate vigorously and passed on to other atoms
- Metals: Has free electrons, which transfers some of their KE to atoms (Speeds up conduction)

Question 27

What is convection

Answer 27

The main method of energy tranfer in fluids

Question 28

The convection process

Answer 28

• The heated liquid causes expansion and leads to a lower density
• Low dense material float on top
• The warm liquid starts to cool and become denser and sinks down