transfer of hear energy and its effects

Question 1

what is the SI unit for temperature

Answer 1

K(kelvin)

Question 2

Temperature changes occurs when heat energy is transferred from

Answer 2

a region of higher temperature to a region of lower temperature

Question 3

heat energy=

Answer 3

thermal energy

Question 4

effects of heat

Answer 4

expansion and contraction

Question 5

When an object is heated, its _________ remains the same

Answer 5

mass

Question 6

When an object is heated, its _________ increases

Answer 6

volume

Question 7

Therefore, when an object is heated, its _________ decreases

Answer 7

density
because density=mass/volume,
less density=same mass/more volume

Question 8

heated air ______

Answer 8

rises because less dense than surrounding air

Question 9

example of hot air rises

Answer 9

hot air balloon

Question 10

how is heat transferred

Answer 10

• Conduction
• Convection
• Radiation

Question 11

what is convection

Answer 11

the transfer of heat through fluid(liquid/gas) caused by the molecule motion

Question 12

what is conduction

Answer 12

the transfer of heat or electrical current from one substance to another through physical contact

Question 13

what is radiation

Answer 13

energy that is radiated or transmitted in the form of rays, waves or particles

Question 14

How do particles (atoms and molecules) transfer energy to each other?

Answer 14

• Collisions
• One molecule collides with another molecule and passes on kinetic energy
• Molecule with greater KE passes energy to the molecule with less KE

Question 15

sort the states of matter in increasing order based on which one expands the most when subjected to the same change in thermal energy?

Answer 15

gas>liquid>solid

Question 16

why conduction and convection of thermal energy from the sun cannot take place in outer space?

Answer 16

• Space is a vacuum
• There are no particles for conduction and convection to take place

Question 17

how does sea breeze work/happen

Answer 17

In the daytime, the land heats up faster than the sea. Warm air above the land becomes less dense and rises.
Cool air above the sea which is denser moves towards the land. This sets up a convection current known as the sea breeze.

Question 18

describe, using particles, how heat is transferred in metal pipes by conduction

Answer 18

when the pipe is heated, particles will gain more energy and vibrate more. These particles bump/collide into nearby particles and transfer some of their energy to them. this continues from the hot end down to the colder end of the object

Question 19

what is the application of bimetallic strips

Answer 19

• fire alarms(old school)
• oven alarm

Question 20

what are the 2 bimetallic strip materials that go together

Answer 20

• brass and steel
• copper and iron

Question 21

how does a bimetallic strip work (in a fire alarm)

Answer 21

when the bimetallic strip is heated, it would bend more towards the side of the steel/iron. the bimetallic strip would touch the electrical wire and complete the electric circuit. this would cause the fire alarm to ring.

Question 22

what material is worse radiator of heat

Answer 22

• white
• smooth
• shiny

Question 23

how to make bimetallic strip go back to original shape

Answer 23

let it cool down

Question 24

what material is better radiator of heat

Answer 24

• black
• matte
• rough

Question 25

why hot air rise

Answer 25

gain heat, less dense & rise.

Question 26

how is heat transferred in metal pipes by conduction

Answer 26

• conduction occurs when a sustance is heated, particles will gain more energy, and vibrate more.
• these particles then bump into nearby particles and transfer someof their energy to them, this continues from the hot end down to the colder end of the substance.