Download Heat Energy Transfer

3 Methods of Heat Transfer
Nothing in the textbook!
Heat Transfer
Lesson aims:
To understand CONDUCTION, CONVECTION
and RADIATION.
Conduction
1. Listen once.
2. Listen again, take notes.
3. Construct an explanation with a partner.
Conduction (only occurs in solids)
• Hot particles vibrate a lot
• Cool particles vibrate a little
Conduction
• Fast-moving particle (lots of energy) collide
with neighbouring particles
• This gives them more energy, making them
vibrate faster
Conduction
• This continues along the length of the solid
until all the particles are vibrating with lots
of energy
Conduction
1. Listen once.
2. Listen again, take notes.
3. Construct an explanation with a partner.
Conduction (mainly occurs in
solids)
• Hot particles vibrate a lot
• Cool particles vibrate a little
Conduction
• Fast-moving particle (lots of energy) collide
with neighbouring particles
• This gives them more energy, making them
vibrate faster
Conduction
• This continues along the length of the solid
until all the particles are vibrating with lots
of energy
Conduction
1.
2.
3.
4.
Listen once.
Listen again, take notes.
Construct an explanation with a partner.
Now check!
Conduction (only occurs in solids)
• Hot particles vibrate a lot
• Cool particles vibrate a little
Conduction
• Fast-moving particle (lots of energy) collide
with neighbouring particles
• This gives them more energy, making them
vibrate faster
Conduction
• This continues along the length of the solid
until all the particles are vibrating with lots
of energy
Another demo…
Conduction Investigation
Investigation:
Which substance is the best conductor?
brass
iron
glass
Predict, in your books, which material you
think will be the best CONDUCTOR, and which
the best INSULATOR.
Conduction Investigation
How do you think this experiment works?
Conduction Investigation
Conclusion:
Brass is the best conductor, glass is the best
insulator (or worst conductor).
This is because the bonds between the atoms in
metals are not as strong as in glass (nonmetals). Therefore, the particles are better able to
vibrate and transfer heat energy.
Heat Transfer
Lesson aims:
To understand CONDUCTION, CONVECTION
and RADIATION.
Convection Demonstration
How does this
happen?
Convection Investigation
What will happen when
purple dye is put in a
beaker, and the water is
heated?
Set it up and try.
A CONVECTION
CURRENT is created.
Why do some objects FLOAT or
SINK??
What do you remember
about density?
Convection (only occurs in fluids)
• A fluid is a liquid or a gas
• One part of the fluid gets heated – the
particles move around with more energy
•“Hot” particles are
more spaced out
so they are less
dense, and rise
•“Cool” particles or
closer together so
they are more
dense, and fall
A better demonstration of this…
Now…
Find the steps of the creation of a
CONVECTION CURRENT and put them in
order.
You are allowed to write down NUMBERS
ONLY!!
(They may be around the room or outside…)
The process…
D. Particles are heated up.
B. The particles with more energy move around
more.
F. The faster moving particles take up more space.
C. Their density is lower.
E. The lower density fluid rises.
G. This pushes the cooler fluid down.
A. A convection current is created.
Heat Transfer
Lesson aims:
To understand CONDUCTION, CONVECTION
and RADIATION.
How does…
energy reach us from the sun??
Radiation
• When heat is moved from one place to another
without using particles, it is called radiation
• Heat radiation is infrared energy waves
Radiation
• These energy waves can travel through any
type of material but can be blocked by
anything that is too thick or dense
• Heat radiation can travel through a vacuum
– this is how the heat from the Sun reaches
us
How else can thermal energy
move?
• All objects transfer
thermal energy by
infrared radiation.
• The hotter an object
is, the more infrared
radiation it gives
off.
Radiation
• No particles are involved in
radiation, unlike
conduction and convection.
• This means that thermal
energy transfer by
radiation can even work in
space, but conduction and
convection cannot.
Radiation Investigation
Put 100ml of water into
cans of different colours.
Put a lamp close to the
cans.
Measure the temperature
every minute.
Conclusion
The dark cans gained the most heat, whereas
the metallic cans gained the least.
This is because the shiny and light coloured
surfaces reflect the radiated heat from the
lamp.
However, the dull and dark surfaces absorbed
the heat.
Radiation Investigation II
Repeat the same investigation, but with hot
water (and no light).
HYPOTHESIS?
BONUS ACTIVITY!
Thermos Flasks…
Does anyone have one of these?
What is it used for?
BUT HOW??!
Thermos flasks…
In your group, explain
what is going on!
Think about how
CONVECTION,
CONDUCTION and
RADIATION are being
reduced…
Tight fitting
insulated bottle cap (lid)
Tight fitting so that there’s less (almost none)
heat transfer by convection
Insulated so that there’s hardly any heat transfer
by conduction
Glass bottle or stainless
steel (unbreakable ?)
with hollow container walls and
no particles inside i.e. vacuum
- So no heat transfer by
conduction or convection
Silvered
(bright and shiny) inside and outside
covering
this limits the amount of heat
transfer (absorption and
emission) by radiation
Insulated placers to keep the bottle safely and
firmly in place, and away from the outside wall of
the container
Thermos lid/cup
Heat Transfer
Lesson aims:
To understand CONDUCTION, CONVECTION
and RADIATION.
BONUS ACTIVITY
2!
BIG HEAT TRANSFER QUIZ
Answers on your whiteboards…
Q: Heat is a form of..
A: Energy
.
Q: Heat will travel
along this rod by...
A: Conduction
Q: Heat can travel through
space by the process of ...
A: Radiation
Q: A material which does not
conduct heat is called an...
A: Insulation
Q: There are no particles in
space, it is a...
A: Vacuum
Q: Which colour of t shirt
would absorb heat best?
A: Black
Q: When particles are heated
they...
A: Rise
Q: Heat can travel through metals
by conduction so they are called....
A: Conductors
Q: When particles in a metal are heated
they start to
more
A: Vibrate
Q: Heat can only travel by
convection in a
or
A: Liquid or Gas
Q: Which colour of teapot would
keep your tea hotter for longer?
A: Silver
Heat Transfer
Lesson aims:
To understand CONDUCTION, CONVECTION
and RADIATION.
Energy Sources
Lesson aims:
To know how the world meets its energy needs.
To consider how energy production may change in the future.
Energy Sources
Task:
A case study on a country’s energy production
Research a country’s method of creating electricity.
Go to the following page for information on the task
requirements (1 period only).
www.bit.ly/energyresourceposter
You will be given a country at random…
The COUNTRIES:
1.
2.
3.
4.
5.
6.
7.
8.
Sweden
UK
Brazil
Argentina
Vietnam
China
Japan
France
9. Australia
10.Thailand
11.USA
12.Germany
13.Denmark
14.Egypt
15.Canada
Market Place Activity
1. One of you will present the information on your poster.
2. The other will go and find out about other countries.
3. Make notes and record information to share with your
partner.
4. Swap roles after 3 countries.
5. Return to your seat.
6. Complete notes on 3 countries.
GO!!