Chapter 9: Heat Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is heat?

A

energy that makes an object hot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is another name for the energy from Sun that is reflected back by clouds?

A

thermal energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is heat in humans?

A

digestion

metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the difference between heat and temperature?

A

Heat:

  • form of energy
  • object absorb heat=hotter
  • object loses heat = colder
  • measured in joule(J)
  • flows from hotter to cooler

Temperature:

  • the measure of degree of hotness or coldness of an object
  • thermometer is used
  • Unit: celcius(℃) and kelvin (K) [Extra: Farenheit(℉)]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the factors that affect heat?

A

TQT=抬起头,太阳在那儿(tai yang=heat)

Type
Quantity
Temperature of material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the factors that affect temperature?

A

degree of movement of particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why when a spark fall on your hand, you don’t feel any pain, but a few drops of boiling water will?

A

Amount of heat in the spark is less than the amount of heat in the drops of boiling water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Does two objects at the same temperature have the same amount of heat

A

No, objects at the same temperature may not have the same amount of heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

From which temperature to which temperature does heat energy travels to?

A

Higher temperature to lower temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the relationship between the difference in temperature and heat flow?

A

The greater the difference in temperature, the faster the heat flows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

State 3 ways that heat travels.

A
  • convection
  • conduction
  • radiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is conduction?

A

The process at which heat flows from the hot to the cold end of solid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Do particles in the medium flow?

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

try to explain the concept of conduction.

A

the particle of the solid are arranged very
closely together (1),
particle that recieve heat energy directly vibrate FASTER, collide with neighbouring particle FREQUENTLY(2),
in this way heat is transferred to the cold end of spoon (3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is convection?

A

The process in which heat is transferred from one place to another by particles which move (move to transfer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does convection occur in?

A

liquids and gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Try to explain convection.

A

When fluid is heated, it expands and becomes less dense, causing it to move upwards (1)
The cold and dense fluids moves downwards to take it’s place (2)
This in turn gets heated and rises and repeats the cycle (3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is radiation?

A

The transfer of heat through vacuum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Does radiation require any medium?

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Give an example of radiation.

A

The heat of the Sun is transferred to the Earth by radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Can the thermometer be placed on top of the lighted bulb?

wants to have the temperature through radiation

A

No, to prevent heat from beig transferred to the thermometer through convection, since hotter air goes up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Can the thermometer be places in contact with the lighted bulb?
(wants to have the temperature through radiation)

A

No, to prevent heat from being transferred to the thermometer through conduction.

23
Q

Why is only radiation used in the warming of earth?

A

Because there is no medium in space to transfer the heat

24
Q

Try to explain how sea breeze is formed.

A

During the day, both land and sea absorb heat from the Sun. Since the land becomes hot faster than the sea, the air above land is heated, becomes less dense and rises, meanwhile cool air above the sea moves towards the land to take the place of the hot air.And this is why wind blows from the sea to the land

25
Q

Try to explain how land breeze is formed.

A

At night, the land cools faster than the sea, therefore, the sea is warmer than the land. The air above the sea rises as it is hotter, while cool air above te land moves towards the sea to occupy the place left by the warm air. And this is why wind blows the land to the sea.

26
Q

What are heat conductors?

A

Substances which conduct heat rapidly and becomes hot or cold quickly

27
Q

What are heat insulators?

A

Substances which do not conduct heat and prevent heat from flowing.

28
Q

State some examples of heat conductors

A
  • mercury
  • silver
  • copper
  • aluminium
  • zinc
  • iron
  • lead
29
Q

State some examples of insulators.

A
  • water,ice
  • glass
  • rubber
  • wood
  • cotton
  • asbestos
  • plastic
  • polystrene
  • air
30
Q

What is thermal equilibrium?

A

When 2 objects reach the same temperature when in thermal contact

31
Q

What happens when solid is heated?

A

Particles in solid vibrate faster, causing them to move apart from on another, making the solid expand, so their volume increases

32
Q

What happens when solid is cooled?

A

Particles in solid vibrates slower, causing them to move closer to one another, making it contract, so their volume decreases

33
Q

What is the observation of this picture (after heating)?

https://drive.google.com/file/d/1XQWdJue1ClZG3dZiZ9hBk1KWsqyZL78F/view?usp=sharing

A

The ball cannot go through the ring

34
Q

Why could the ball go through the ring again after cooling?

A

because the ball contracted

35
Q

What happens when liquid or gas is heated?

A

Particles move faster and randomly, causing the distance between particles increase, making te liquid or gas expand, so their volume increases

36
Q

What happens when liquid or gas is cooled?

A

Movement of the particles slow down and move closer to one another,making it contract, so their volume decreases

37
Q

Why did the balloon become inflated when put in hot water?

A

Air in the bottle expands, and then moves into the balloon.

38
Q

Why did the balloon become deflated when put into cold water?

A

air in balloon contracted, moving back into the bottle

39
Q

Why did the coloured liquid droplet in flask moves downwards when put in ice?

A

air inside the flask contracts because it lost heat

40
Q

Why did the coloured liquid droplet in flask moves upwards in hot water?

A

air inside the flask expands because it absorbs more heat

41
Q

Try to explain the use of expansion and contraction in thermometer.

A

When the surrounding temperature rises, the mercury expands and columns up to the capillary tube.
But when the surrounding temperature falls, the mercury contracts and returns to the bulb

42
Q

How is a bimetallic strip formed?

A

combining 2 types of different metals that have different rates of expansion and contraction

43
Q

What will happen when the bimetallic strip is heated?

A

It will curve with the metal with higher expansion rate on the outside

44
Q

What will happen when the bimetallic strip is put into cold surrounding?

A

It will curve with the metal with lower expansion rate on the outside

45
Q

Why are there small gaps between sections of rail?

A

to allow the tracks expand

46
Q

Why are electric cable and telephone wires fitted loosely?

A

to allow room for expansion and contraction

47
Q

How did people solve the expansion of a curved bridge?

A

One end of bridge is fixed while the other rest on rollers, so when it expands or contracts, it wont be damaged

48
Q

How to make a dented ball return to its original shape?

A

put it in hot water, as the air in ball expands, the ball will no longer be dented

49
Q

How to open a tighten jar lid?(if plastic cannot save u dy ahhaa)

A

put it in hot water, as (jar lids mostly are metal) metal absorbs heat faster and expands faster

50
Q

What does the amount of heat that is absorbed depends on?

A

type and colour of surface

51
Q

What type of surface absorbs heat better?

A

dark and dull

52
Q

Is a good heat radiator also a good heat absorber?

A

yes

53
Q

State the heat concepts used in daily life by using green building technology.

A
  • Using recycled materials
  • Using water efficiently
  • Using renewable energy
  • Using environment-friendly equipment
  • Reducing damage to the original landscape
  • Using good ventilation, drainage and lighting system
54
Q

What are the 10 ways to make our home eco-friendly?

A
  • eco-friendly building materials
  • LED lightning
  • solar panels
  • household water conversion
  • wind turbines
  • harness geothermal energy
  • sustainable insulation
  • energy efficient appliances
  • water re-use
  • rainwater harvesting