Ch.5.3

Question 1

The energy ________________ from a ________________ object to a ________________ one is called heat.

Answer 1

transferred, hotter, colder

Question 2

Three methods of heat transfer:
1.
2.
3.

Answer 2

Conduction
Convection
Radiation

Question 3

Conduction requires a ________________ (such as a ________________, a ______________ or a ______________) to transfer heat.

Answer 3

medium, solid, liquid, gas

Question 4

-

Answer 4

an object

between two objects in contact

Question 5

heat can be transferred by conduction through an object from the __________ end to the _________ end. Heat can be conducted in __________ _________________.

Answer 5

hot, cold

any direction

Question 6

some materials conduct heat ______________ ____________ ______________.

Answer 6

faster than others

Question 7

________________ such as ________________ and ________________ conduct heat ________________.
They are ________________ ________________ of heat.

Answer 7

Metals, copper, iron, fast, good conductors

Question 8

In general, _____________-________________ conduct heat more ________________. They are ________________ ________________/ ________________ of heat.

Answer 8

Non-metals, slowly, poor conductors, insulators

Question 9

Please list out 7 items in the order of poor conductor of heat->good conductor of heat.
1.
2.
3.
4.
5.
6.
7.

Answer 9

Plastic
Wood
Glass
Stainless steel
Iron
Aluminium 
Copper

Question 10

In general, liquids are ________________ ________________ of heat.

Answer 10

poor conductors

Question 11

________________ and _____________ are poor conductors of heat.

Answer 11

Water, air

Question 12

Uses of good conductors of heat:

• some ________________ ________________ are made of good conductors of heat such as ____________ and ________________
• these materials transfer heat very ______________ to the ___________
• this ________________ cooking time
• a ________________ ________________ is one of the components inside a ________________
• it is made of metal which can ________________ _____________ ____________ to _____________ the computer from _________________

Answer 12

Cooking utensils, iron, copper, quickly, food, reduces, heat sink, computer, conduct heat away, prevent, overheating

Question 13

Uses of poor conductors of heat:

• most of the ________________ of ________________ ________________ are made of poor conductors of heat
• ____________ and ________________ can ________________ a lot of ________________ inside them
• since air is a poor conductors of heat, we can wear _________ or _____________ ________________ to keep warm
• similarly, animals like ________________ ________________ keep warm by ________________ __________ in their ___________

Answer 13

Handles, cooking utensils, fur, feathers, trap, heat, fur, down clothings, polar bears, trapping air, fur

Question 14

In a ______________ ______________, hot water ______________ and cold water in the tube ______________ to take the place of the ______________ ______________ ______________. This cycle carries ______________ from ______________ ______________ to ______________ through _________________.

Answer 14

convection current, rises, sinks, risen hot water

heat, one place, another, convection

Question 15

Convection in ______________ takes place in the ______________ ______________ as in liquids. When the air above the candle flame gets ______________, it ______________. The ______________ air from the __________________ ______________ to take the place of the ______________ air. The ______________ of air forms a ______________ ______________ of air.

Answer 15

gases, same way, hot, rises, cold, surroundings, sinks, hot, movement, convection current

Question 16

Similar to conduction, convection requires a _____________ to transfer heat.
However, convection can take place only in _________________ and _________. It cannot take place in _____________.

Answer 16

medium, liquids, gases, solids

Question 17

Some electrical appliances make use of convection:

• the _____________ _____________ of an electric kettle is placed at the _____________ so that heat can be transferred by a _____________ _____________.
• an air conditioner is usually _____________ near the _____________. __________ air is blown out and _____________ while ________ air _____________ to _____________ it. A _____________ _____________ is formed and the room is _____________.

Answer 17

heating element, bottom, convection current

installed, ceiling, cold, sinks, hot, rises, replace, convection current, cooled

Question 18

We can observe many _______________ showing convection of heat in ________________: _____________ _____________ and _____________ _____________ are the effects of convection currents.

Answer 18

phenomena, Nature, sea breezes, land breezes

Question 19

Sea breezes: during the day, land _____________ heat from the Sun _____________ than sea water and the land becomes ________________________________________. Hot air _____________ from land and cold air _____________ in from the sea to replace the ______________________________________.

Answer 19

Absorbs, faster, hotter than the sea, rises, blows, hot air that has risen

Question 20

Land breezes: at night, the land _____________ _____________ faster than the sea and the land becomes _____________. Hot air rises from the _____________ and cool air blows from _____________ to _____________.

Answer 20

Cools down, colder, sea, land, sea

Question 21

The space between the ____________ and the _________________ is a _________________. Heat cannot be transferred through a vacuum by _________________ or _________________. This is because both processes require a _________________ to _________________ ____________.

Answer 21

Sun, Earth, vacuum, conduction, convection, medium, transfer heat

Question 22

Heat is transferred from the Sun to the Earth by _________________. Another example in real life is when we sit near an _________________ _________________, heat is transferred to us mostly by _________________.

Answer 22

Radiation, electric heater, radiation

Question 23

All objects _________________ radiation. For example, when we stand under the Sun, our bodies _________________ _________________ from it and our body temperature will _________________.

Answer 23

absorb, absorb radiation, increase

Question 24

In general, _________________ ________________ _________________ are _________________ absorbers of radiation, while _________________ _________________ _________________ are _________________ absorbers of radiation.

Answer 24

dull black surfaces, good, shiny silver surfaces, poor

Question 25

It is more comfortable to wear _______________-_________________ _________________ in summer as they absorb _________________ radiation from the Sun than ______________-_________________ _________________. Therefore, they help us stay _________________.

Answer 25

light-coloured clothes, less, dark-coloured clothes, cool

Question 26

All objects also _________________ radiation. Dull black surfaces are _________________ emitters of radiation while shiny silver surfaces are _________________ emitters of radiation.
Good/ poor absorbers of radiation are also _________________/ _________________ emitters of radiation.

Answer 26

emit, good, poor, good, poor

Question 27

The _________________ _________________ behind a refrigerator is usually painted black so that it _______________________________________________________.

Answer 27

heat radiator, loses heat easily by radiation

Question 28

Cooking utensils with _________________ _________________ can help keep water or food ___________________________________________________.

Answer 28

Shiny surfaces, hot for a longer period

Question 29

the following parts of a vacuum flask prevent heat transfer through:

• the stopper-> _________________
• the silver glass walls-> _________________
• the vacuum between walls-> _________________+ _________________
• stopper and support (which are usually made of _________________ or _________________ and are _____________ ______________ of heat)-> _________________

Answer 29

convection
radiation
radiation and convection
plastic, cork, poor conductors, conduction