[TP] thermal physics

Question 1

what is the kinetic theory of matter?

Answer 1

the kinetic theory of matter states that matter is made up of tiny particles that are in constant random motion

Question 2

what are the characteristics of the three states of matter?

Answer 2

difference in shape, volume, ease of flow and compressibility

Question 3

describe the characteristics of a solid

Answer 3

• fixed shape
• fixed volume
• do not flow
• not compressible

Question 4

describe the characteristics of a liquid

Answer 4

• do not have fixed shape, they take the shape of their container
• have a fixed volume
• flows
• not compressible

Question 5

describe the characteristics of a liquid

Answer 5

• do not have fixed shape (takes the shape of their container) and volume
• flows
• compressible

Question 6

what is the attraction between particles in a solid?

Answer 6

there are strong forces of attraction between particles in a solid

Question 7

what is the attraction between particles in a liquid?

Answer 7

the force of attraction is weaker than in gas but stronger than in gas

Question 8

what is the attraction between particles in a gas?

Answer 8

the particles in a gas experience very weak forces of attraction

Question 9

how are particles arranged in a solid?

Answer 9

particles in a solid are arranged in a fixed, regular pattern

Question 10

how are particles arranged in a liquid?

Answer 10

particles are slightly further apart than in solid, closer than in gas

Question 11

how are particles arranged in a gas?

Answer 11

particles in a gas have no fixed positions and no regular pattern

Question 12

how do particles in a solid move?

Answer 12

particles in a solid vibrate about fixed positions

Question 13

how do particles in a liquid move?

Answer 13

particles in a liquid slide past one another

Question 14

how do particles in a gas move?

Answer 14

particles in a gas move freely and randomly at high speeds, occupying any available space

Question 15

what happens to matter when it is heated?

Answer 15

it gains heat and expands

Question 16

what happens to matter when it is cooled?

Answer 16

it loses heat and contracts

Question 17

does the mass of matter change when it expands or contracts?

Answer 17

no - the mass remains the same

Question 18

why does matter expand when heated?

Answer 18

heating adds thermal energy, causing particles to vibrate more and move apart

Question 19

why does matter contract when cooled?

Answer 19

cooling removes thermal energy, causing particles to vibrate less and move closer together

Question 20

what are some negative effects of thermal expansion?

Answer 20

some examples are road cracking on hot days and warping of materials like railway tracks

Question 21

what is heat?

Answer 21

heat is the transfer of thermal energy from hot to cold regions

Question 22

what is temperature?

Answer 22

temperature is the measure of hotness and coolness

Question 23

what is conduction?

Answer 23

conduction is the transfer of thermal energy without the physical movement of the medium and is most effective in solids

Question 24

what is temperature measured in?

Answer 24

it is measured in Kelvin(K)

Question 25

what are some other units of temperature?

Answer 25

degree fahrenheit and degree celsius

Question 26

how does temperature relate to the average speed of particles in a substance?

Answer 26

higher temperature =. higher average speed lower temperature = lower average speed

Question 27

does the temperature of an object depend on its size or material?

Answer 27

no, temperature is independent of size or material

Question 28

how does the size of an object relate to the amount of thermal energy it contains?

Answer 28

larger objects contain more thermal energy due to their greater volume

Question 29

what is conduction?

Answer 29

conduction is the transfer of thermal energy without the movement of the medium. it can occur in any state of matter.

Question 30

why is conduction most effective in solids?

Answer 30

in solids, particles are closely packed, allowing for faster energy transfer through vibrations

Question 31

why are air and water poor conductors of heat?

Answer 31

in fluids, particles are spaced further apart, resulting in slower energy transfer through collisions between the particles

Question 32

explain the transfer of thermal energy through conduction

Answer 32

particles at the hotter end gain energy, vibrate more vigorously, and transfer kinetic energy to neighbouring particles through collisions

Question 33

what are good conductors of heat, and why

Answer 33

materials that allow more heat transfer this is because they possess free moving electrons that help transmit energy

Question 34

what are poor conductors of heat, and why

Answer 34

materials that allow little heat transfer this is because they lack free-moving electrons and hinder energy transmission

Question 35

what is convection?

Answer 35

convection is the transfer of thermal energy by the physical movement of a medium and occur in liquids and gases.

Question 36

how does convection work in a liquid/gas

Answer 36

the fluid at the bottom will gain heat and expand, becoming less dense and rises the cooler denser fluid will sink, creating a convection current that transfers heat

Question 37

why is the cooling unit at the top in a refrigerator?

Answer 37

cool air being denser sinks to cool the contents, while warmer air warmed by the contents rises and is cooled by the unit. this creates a convection current

Question 38

what is radiation?

Answer 38

radiation is the transfer of thermal energy from a hotter body to a cooler body without a medium, and it can pass through a vacuum.

Question 39

what four factors affect the rate of heat transfer by radiation?

Answer 39

surface colour, texture, temperature and the material’s ability to absorb or emit radiation

Question 40

what are good absorbers and emitters of radiation?

Answer 40

dull black surfaces

Question 41

what are poor absorbers and emitters of radiation?

Answer 41

shiny silver surfaces

Question 42

how does surface temperature affect radiation emission?

Answer 42

higher surface temperature leads ton a higher rate of emission of radiation

Question 43

how does the surface area of an object affect radiation emission and absorption?

Answer 43

objects with larger surface areas emit or absorb more heat per second compared to objects with smaller surface areas

Question 44

what material should be used to keep something warm in a cooler environment?

Answer 44

shiny silver material

Question 45

what material should be used to keep something cool in a warm environment?

Answer 45

a shiny silver material

Question 46

how can a vacuum be used to reduce heat transfer?

Answer 46

placing a vacuum between silvered surfaces reduces heat loss through conduction and convection

Question 47

how does a cap on a vacuum flask reduce heat loss?

Answer 47

it reduces heat loss through convection and evaporation