transfer of thermal energy 🌬

Question 1

define conduction

Answer 1

conduction is the transfer of thermal energy through a medium without any flow of the medium

Question 2

describe the process of conduction in non-metals

Answer 2

• particles at the hotter end gain kinetic energy and vibrate more vigorously about fixed positions
• particles collide with neighbouring particles, transferring kinetic energy to the cooler end

Question 3

describe the process of conduction in metals

Answer 3

• particles at the hotter end gain kinetic energy and vibrate more vigorously about fixed positions
• particles collide with neighbouring particles, transferring kinetic energy to the cooler end
• free eelectrons move at greater speeds from the hotter end to the cooler end, transferring kinetic energy from the moving electrons to particles during collisions

Question 4

define convection

Answer 4

cinvection is the transfer of thermal energy by means of convection curremts in a fluid due to difference in density

Question 5

descrbe the process of convection in a food container with an ice pack on top

Answer 5

air nearest the ice pack cools, contracts, becomes dennser and sinks. the warmer air at the bottom of the box which is less dense. rises. this sets up a convection current

Question 6

define radiation

Answer 6

radiation iis the transfer of thermal energy in the form of electromagnetic waves such as infrared radiation without the aid of a medium

Question 7

radiation surfaces

Answer 7

• dull, black: good absorber and emitter
• shiny, silver: poor absorber and emitter