Transcript 9E * Reactions of metals and metal compounds

TODAY – starting P3
• LO: Describe some different types of
renewable energy [C] Know how energy is
generated in power stations [B]
STARTER
List as many renewable energy sources that you can think of!
Renewable vs Non-Renewable
• Fossil fuels are non-renewable, once they
have been burnt they cannot be used
again and it will take millions of years for
them to re-form.
• Renewable energy
• Solar Power
sources
do
not
• Wind Power
run out and can
• Tidal/Wave power
be used over and
• Hydroelectric power
over again.
• Geothermal energy
Examples are
Fossil Fuels
• The three fossil fuels are coal, oil and gas.
• They can be burnt in a power station to
generate electricity.
• Because the electricity has to be
produced from another energy form we
call it a secondary energy source.
• Electricity cannot be stored, so it has to
be generated all the time.
How a power station works
Fuel is burnt to
heat water which
produces steam
The steam turns
a turbine
The turbine drives
the generator
which creates
electricity
A transformer is two
coils of wire on an iron
core. It changes
electricity into a higher
voltage so it can be sent
around the national grid
at 400000v
How a power station works
Task
• Using the templates and the information
sheets create fact files for at least 4
different energy types.
• HINT: It is a good idea to do Nuclear as one
• Things to include:
– How does it generate electricity (C)
(include a diagram if necessary)
– Advantages (B)
– Disadvantages (B)
Extension Task (A)
• You are a local politician and have been
asked to help decide which type of
power station you will have in your local
area.
• Which one will you choose and why??
• Things to think about: What is the area
you live in like? Does it have many
people? Does it have much space? What
is the weather like?
Energy Sources
Energy
source
Advantage
Disadvantage
TITLE - efficiency
• LO: how to calculate the efficiency of
appliances [B] how to represent energy
transfer using a Sankey diagram [C] how we
can make buildings more energy efficient [D]
STARTER
When you eat a burger what does your body use the energy for?
Make a list!
Energy efficiency
efficiency = energy usefully transferred × 100%
total energy supplied
• Energy efficiency is a measure of how much
useful energy an appliance makes compared
to how much initial energy is put into it
• The more efficient it is
the better as it saves
money and resources
• We can show efficiency
using a diagram
Efficiency questions
1. Kettle – Input energy: 250j Useful output:
150j 60 %
2. Toaster - Input energy: 150j Useful output:
120j 80 %
3. Microwave - Input energy: 500j Useful
output: 190j 38 %
4. Television - Input energy: 250j Useful
output: 200j 80 %
5. Hairdryer - Input energy: 150j Useful
output: 80j 53 %
6. Bulb – Input energy: 200j Useful output: 10j
5%
Sankey Diagrams
Show how one type of energy can be
converted into other types of energy.
LAW
Energy can not be created or destroyed it can
only be transformed from one form to
another.
Sankey Diagrams show the FLOW of ENERGY
Normal Light Bulb
Energy Saving Light Bulb
Task
Produce an informative leaflet that gives
advice on how to make your home more
energy efficient
• Grade D – Give at least 3 examples of
ways to make your home more energy
efficient
• Grade C – Explain how each method
makes your home more efficient
• Grade B – Discuss why some methods are
better than others and why (think about
cost vs what you will save)
EXAM QUESTION
• 5 minutes
Thinking Task
• Mr Green is worried that
his energy bills are really
high and he cant afford
to pay them, what advice
would you give him of
how to save money on his
bills??
Wasted Energy
Pick an object
from the
kitchen and
draw an energy
flow diagram
for that item.
Then explain
which is the
wasted and
which is the
useful energy
output.
TITLE – Electrical Energy
• LO: know how and when to use ‘electrical
energy’ equations
STARTER
Use the efficiency equation: efficiency =
useful energy X100
total energy
•A light bulb is supplied with 20 000 J of energy. 19 000 is wasted
as heat. How efficient is the bulb?
5%
Power (W)
Voltage (V)
X
Current (A)
Energy Transferred (J)
Power (W)
X
Time (s)
Energy Transferred
(Kilowatt-Hours)
Power (kW) X
Time (hrs)
Cost
Number of kWh
X Cost per kWh
Efficiency =
Energy Usefully Transferred
Total Energy Supplied
X 100
Task
Produce a revision guide page that include the
‘Electrical Energy’ equations.
D – include information on power, electricity
and energy
C – include all 4 formula triangles
B – create your own worked examples for each
formula triangle
Extension – write some quiz questions on this topic
Quiz – which triangle?
An exam question gives you
information that includes
Power is 600W and the Voltage is 30V
what is the current?
20 A
An exam question gives you
information that includes
You use 40kWh of electricity at a cost of
2 p per kWh, what is the cost?
80p
An exam question gives you
information that includes
Work out the power. 600kWh of energy is
transferred in 3 hours.
200 kW
An exam question gives you
information that includes
400 J of energy is transferred at a power
of 80 W. How long does this take?
5s
Objectives
• Describe how energy is produced from
fossil fuels
Starter Activity
• List 2 non-renewable and 2
renewable energy sources
• Give one advantage and one
disadvantage for each type
Objectives
• Describe how energy is produced from
nuclear sources
Nuclear Power
• Certain radioactive materials can be
used to produce electricity in a power
station instead of using fossil fuels.
• The nuclear fuel is not burned though
like fossil fuels. It is put into a nuclear
reactor and nuclear fission occurs.
• Nuclear fission releases huge amounts
of heat energy that is used to heat
water, creating steam to turn a turbine.
Nuclear power generator
Control rods
control the
speed of the
nuclear reaction
(Uranium fuel rods)
What is Ionising Radiation?
• Ionising radiation is given off by
radioactive particles.
• It is called ionising because it has enough
energy to collide with atoms and knock
electrons off it causing it to become a
positively charged particle called an ion.
• Ionised atoms have more energy so are
more likely to react chemically and damage
cells in the human body, causing cancer.
Uses of Ionising Radiation
• Ionising radiation can be useful as it can
be used to sterilise surgical equipment,
kill cancer cells, as radioactive tracers
and to preserve fruit.
• Generally however it is harmful and
causes cancer so we must limit the
doses we are exposed to e.g. X rays.
• We can protect ourselves by using lead
and concrete to stop it and monitoring
how much we are exposed to.
Task: Using pages 234-235 of the textbook and the internet
create an informative poster or PowerPoint explaining:
– How a nuclear power station works and
include a diagram of the nuclear
reactor (C)
– How the nuclear waste from the power
station is dealt with (B)
– What nuclear fission is and how the
chain reaction occurs (A)
Geiger-Müller Counter
• Radioactivity can be
detected using a
Geiger-Müller Counter.
• When radiation enters the tube, atoms
inside are ionised by the radiation.
• These ions are counted and shown as
counts per second or counts per
minute.
Nuclear Debate
• In pairs you need to come up with
arguments for and against having a
nuclear power station built in Leeds.
Energy resources, Generators
and the National Grid
• LO: Consider environmental impacts of energy sources
as well as cost [D] know that electricity is distributed
by the national grid [C] know how generators use
magnets to make electricity [B]
What is ionising radiation and why is it dangerous?
electron
photon of ionizing radiation
positively charged atom
Ionization happens when a photon with enough
energy hits an atom or molecule inside a material.
How a Generator Works
You can make electricity by
moving a magnet in or near
a coil of wire.
This diagram is one of a
small dynamo to power a
bicycle light but works on the
same principle as large
power station generators.
Answer the Questions
1.
2.
3.
4.
What 4 things would the best energy source be?
Give 2 cost related issues on energy sources
Give 2 environmental issues of energy sources
Using the table on 97 compare the good and bad
points of each energy source
5. Explain how a generator works
6. Why does the National Grid distribute electricity
at a high voltage rather than at a high current?
EXTENSION – construct a mind map using
‘electricity’ as your centre word
Working out the cost