TENAGA HABA

1. Haba

2. What is Heat?
• Suatu bentuk tenaga -
kerana ia boleh
menggerakkan benda
- E.g: Makes a hot air
balloon rise.
- Steam engines
• Diukur dalam unit
JOULES (J)

3. Haba
Haba adalah bentuk tenaga yang boleh
mengalir dari kawasan panas ke
kawasan sejuk

4. Haba boleh bertukar bentuk
• Proses fotosintesis ( Tumbuhan membuat
makanan)
Tenaga cahaya & haba → Tenaga kimia
• Stesen Jana kuasa (Pembakaran minyak
dan gas)
• Tenaga haba → Tenaga kinetik →
Tenaga elektrik

5. Bagaimana haba dihasilkan?
• Pergerakan zarah-zarah menghasilkan
haba.
• Haba dapat dihasilkan melalui geseran,
pembakaran bahan api, tenaga elektrik
dan sebagainya.
• Haba menyebabkan pengembangan dan
pengecutan pepejal, cecair dan gas.

6. Haba Vs Suhu
• The temperature of an object tells us how
HOT it is
• Ukuran darjah kepanasan atau
kesejukkan suatu objek.
• Measured in degrees Celsius - °C

7. Haba Vs Suhu
• It is NOT the same as heat energy
although the two quantities are related.
• e.g. a beaker of water at 60 °C is hotter
than a bath of water at 40 °C BUT the
bath contains more joules of heat energy

8. Pengaliran haba
• Mengalir dari kawasan yang panas ke
kawasan yang sejuk.
• Objek panas dalam bilik akan menjadi
sejuk ke takat suhu bilik.
e.g: air kopi
• Objek sejuk dalam bilik akan dipanaskan
ke takat suhu bilik.
e.g: butter, ice

9. What do you think?

10. Pengaliran haba
3 cara
• Konduksi/ Conduction
• Perolakan/ Convection
• Sinaran/ Radiation

11. Konduksi/ Conduction
• Pengaliran haba dari kawasan panas ke
kawasan sejuk pada suatu pepejal.
• Zarah-zarah pada satu hujung rod pepejal
yang dipanaskan memperolehi tenaga
haba dan bergetar dengan lebih cepat dan
berlanggar dengan zarah-zarah
bersebelahan.
• Tenaga haba dipindahkan kepada zarah-zarah
bersebelahan secara berterusan
dan akhirnya ke seluruh rod logam.

12. Konduksi/ Conduction
• When you heat a metal strip at one end, the heat travels
to the other end.
• As you heat the metal, the particles vibrate, these
vibrations make the adjacent particles vibrate, and so on
and so on, the vibrations are passed along the metal and
so is the heat. We call this? Conduction

13. Why does metal feel colder than wood, if they
are both at the same temperature?
Metal is a conductor, wood is an insulator. Metal
conducts the heat away from your hands. Wood
does not conduct the heat away from your hands as
well as the metal, so the wood feels warmer than
the metal.

14. Perolakan/ Convection
What happens to the particles in a liquid or a
gas when you heat them?
The particles spread out and
become less dense.
A liquid or gas.

15. Perolakan/ Convection
• Proses pengaliran haba melalui bendalir
(cecair dan gas) akibat gerakan bendalir
dari kawasan yang lebih panas ke
kawasan yang kurang panas.

16. Perolakan/ Convection
• Think about when you boil water, the
bubbles move upwards
• Or think of a gas heater in the room, the
heat rises around the room

17. Perolakan/ Convection
Hot water
rises
Cooler
water sinks
Convection
current
Cools at the
surface

18. Perolakan/ Convection
Where is the
cooling
compartment
put in a fridge?
Cooling
compartment
It is put at the top,
because cool air
sinks, so it cools the
food on the way
down.
It is warmer at
the bottom, so
this warmer air
rises and a
convection
current is set up.

19. Convection questions
Why does hot air rise and cold air sink?
Cool air is more dense than warm air, so the cool air ‘falls
through’ the warm air.
Why are boilers placed beneath hot water
tanks in people’s homes?
Hot water rises.
So when the boiler heats the water, and the hot water rises, the water tank
is filled with hot water.

20. How does heat energy get
from the Sun to the Earth? There are no particles
between the Sun and the
Earth so it CANNOT
travel by conduction or
by convection.
? RADIATION

21. Sinaran/ Radiation
• Proses pemindahan haba daripada
suatu sumber haba ke kawasan
persekitarannya tanpa medium
• Mengalir ke semua arah daripada
objek yang panas.
• Semakin panas objek, semakin
banyak haba yang mengalir melalui
sinaran.
• Does the surface affect the way heat
is radiated?

23. Radiation – Think Pair-Share
Radiation travels in straight lines
True/False
Radiation can travel through a vacuum
True/False
Radiation requires particles to travel
True/False
Radiation travels at the speed of light
True/False

24. Radiation questions
Why are houses painted white in hot countries?
White reflects heat radiation and keeps the house cooler.
Why are shiny foil blankets wrapped around marathon runners at the end of a
race?
The shiny metal reflects the heat radiation from the runner back in, this stops
the runner getting cold.

25. Konduktor haba dan
penebat haba
• Konduktor haba – bahan yang
membenarkan haba melaluinya dengan
mudah. e.g: most metals
• Penebat haba – bahan yang menghalang
haba mengalir melaluinya. e.g: wood,
plastic, glass
• Why do many sauce pans have plastic
handles?

26. Konduktor haba Vs Penebat haba

27. Conductor or Insulator?
• Wood?
• Aluminium?
• Plastic?
• Glass?
• Iron?
• Polystyrene?
• Copper?
• Cardboard?

28. Pelbagai Kegunaan konduktor dan penebat
dalam kehidupan harian
Bincangkan…
Pemanas pada dasar cerek elektrik
Periuk dan kuali
Seterika elektrik
Radiator kereta
Merkuri
Kotak ais

29. Pelbagai Kegunaan konduktor dan penebat
dalam kehidupan harian
Rajah di sebelah menunjukkan
struktur binaan sebuah kelalang
termos. Struktur binaan kelalang
termos bertujuan untuk
mengurangkan kehilangan haba.
Bincangkan.

30. Penyerap dan Pembebas haba yang Baik
• Keupayaan suatu objek untuk menyerap
dan membebaskan haba dipengaruhi oleh
ciri permukaan objek (jenis dan warna)
• Permukaan yang gelap dan kusam
menyerap dan membebaskan haba lebih
baik daripada objek putih dan berkilat

31. Emission experiment
Four containers were filled with warm water. Which
container would have the warmest water after ten minutes?
Shiny metal
Dull metal
Dull black
Shiny black
shiny metal
The __________ container would be the warmest after ten
minutes because its shiny surface reflects heat _______ radiation
back
into the container so less is lost. The ________ dull black
container
would be the coolest because it is the best at _______ emitting
heat
radiation.

32. Absorption experiment
Four containers were placed equidistant from a heater. Which
container would have the warmest water after ten minutes?
dull black
The __________ container would be the warmest after ten
minutes because its surface absorbs heat _______ radiation
the best.
The _________ shiny metal
container would be the coolest because it is
the poorest at __________ heat radiation.
absorbing
Shiny metal
Dull metal
Dull black
Shiny black

33. EEmmiitttteerrss
Hotter objects emit (give out) heat
Different surfaces emit heat at different speeds
A dull black surfaces loses energy more
quickly – it is a good radiator
A bright shiny or white surface is a poor
radiator
Marathon runners need to keep warm at the end
of races, covering in shiny blankets reduces
radiation and therefore heat loss.

34. EEmmiitttteerrss ooff hheeaatt
Bright shiny can
Poor radiator
Dull black can
Good Radiator

35. AAbbssoorrbbeerrss
Cooler objects absorb (take in) heat
Substances absorb heat at different speeds
Dull, black surfaces absorb heat quickly
Bright, shiny surfaces absorb heat slowly
In hot countries, people wear bright white
clothes and paint their houses white to reduce
absorption of energy from the sun.
Petrol storage tanks sprayed silver to reflect
sun’s rays

36. AAbbssoorrbbeerrss
Shiny, bright can
Poor absorber
Dull black can
Good absorber

37. Revision
1. Which of the following is not a
method of heat transfer?
A. Radiation
B. Insulation
C. Conduction
D. Convection

38. Revision
1. Which of the following is not a
method of heat transfer?
A. Radiation
B. Insulation
C. Conduction
D. Convection

39. 2. In which of the following are
the particles closest together?
A. Solid
B. Liquid
C. Gas
D. Fluid

40. 2. In which of the following are
the particles closest together?
A. Solid
B. Liquid
C. Gas
D. Fluid

41. 3. How does heat energy reach
the Earth from the Sun?
A. Radiation
B. Conduction
C. Convection
D. Insulation

42. 3. How does heat energy reach
the Earth from the Sun?
A. Radiation
B. Conduction
C. Convection
D. Insulation

43. 4. Which is the best surface for
reflecting heat radiation?
A. Shiny white
B. Dull white
C. Shiny black
D. Dull black

44. 4. Which is the best surface for
reflecting heat radiation?
A. Shiny white
B. Dull white
C. Shiny black
D. Dull black

45. 5. Which is the best surface for
absorbing heat radiation?
A. Shiny white
B. Dull white
C. Shiny black
D. Dull black

46. 5. Which is the best surface for
absorbing heat radiation?
A. Shiny white
B. Dull white
C. Shiny black
D. Dull black

47. Key Words
Heat
Radiation
Convection
Conduction
Cold
Insulator
Conductor
Temperature
Emit
Absorb
Transfer