Transcript P1 - Powerpoint - tonyconnett.com

Monday, 13 April 2015
Btec Level 2 – Phys 1
Aims of lesson:
Lesson 1 – Forms of Energy • Know that energy can
•
exist in many different
forms
Understand where energy
is being changed from one
form to another
Starter Questions
1.
2.
3.
Name 9 different forms of
energy (K….., H……,
S……, L……., E…….,
G……, C……., N…….,
E……….)
What types of energy are
produced by a light bulb?
In question 2 what form of
energy is wasted?
Forms of Energy
Kinetic
Heat
Sound
Light
Electricity
Gravitational
Chemical
Nuclear
Elastic
(moving objects)
(hot objects)
(vibration of air or other medium)
(from luminous objects)
(flow of electricity along a wire)
(‘high up’ objects)
(things you ‘burn’ to release heat)
(atoms that disintegrate to produce heat)
(stretched objects)
Energy Changes
Objects change energy from one form into
another, e.g.
Electricity
Light (useful)
Heat (wasted)
Chemical
Heat (useful)
Light (wasted)
Electricity
Kinetic (useful)
Heat (wasted)
Sound (wasted)
Draw energy diagrams (like the previous ones) for the
following events…
1. A car engine
2. A wind turbine
3. Roller Coaster a
the top of a slope
4. A archer about to
shoot an arrow
5. A battery
6. A nuclear reactor
e.g.
Chemical → Car engine →…. (useful)
→…. (wasted)
Things to do…
• Longman FND. Page
176-177, Q 1-9 &
‘Summary’
• Worksheet E5.1 ‘Types
of energy;
Questions (HT)
1.
2.
3.
4.
5.
6.
7.
The diagram B shows two items that give
out both heat and light energy. Name two
other things that give out heat and light
energy.
Name something that does not use
electricity, but produces sound energy.
Explain what would happen to the water
molecules in a cup of water as the
temperature decreases from 20°C to -20°C.
What would eventually happen to the
particles if the temperature continued to
decrease?
A person sleeping upstairs has gravitational
potential energy. Explain why this energy is
called potential energy.
A blown-up balloon has stored energy.
What is the form of this energy and how
could you release this energy?
What type of energy do both petrol and
13-Apr-15
Module 9 - Energy
Lesson 18 – How we generate our Electricity
Aims:
• How electricity is generated from non-renewable
fuels
• Know how a power station produces electricity
Starter Questions…
1. Name two fossil fuels?
2. Name a renewable fuel?
3. What sort of power station
uses uranium and
plutonium?
Fuels
A “fuel” is something that can be burned to release heat and
light energy. The main examples are:
Coal, oil and gas are called “fossil fuels”. In
other words, they were made from fossils.
Power stations
Boiler
Transformer
Turbine
Cooling
tower
Generator
What does
each part do?
The boiler is where the fuel is burnt to boil
water
The steam from the boiler is used to turn a
turbine
The turbine is connected to the generator,
which acts like a dynamo – it generates
electricity out of movement
The steam is cooled down and turned back
into water in the cooling tower
Nuclear power stations
These work in a similar way to normal power stations:
The main difference is that the nuclear fuel is NOT
burnt – it is used to boil water in a “heat exchanger”
Relatively
Advantages of non-renewable
fuels
Reliable
cheap
Coal, oil
and gas
Relatively
easy to find
Flexible in
meeting
demand
Cheap fuel
costs
Don’t produce
as much
pollution
Nuclear
The problems…
Power stations using coal, oil, gas or nuclear fuels can certainly
whack out the energy, BUT…
Problem 1 –
Fossil fuels and nuclear sources will RUN OUT
Problem 2 –
Burning fossil fuels will pollute the atmosphere
Problem 3 -
Nuclear plants run the risk of contamination and the
cost of shutting them down (“decommissioning”) is
very high
So what’s the solution?
13-Apr-15
Things to do…
Questions:
(blockbusters)
Longman FND, book 1. Page 192-193.
Q 1-7 & ‘Summary’
Homework:
Worksheet E14.1 ‘Power Stations’
1.
2.
3.
4.
Explain how steam is used to generate electricity
What fuels can be used in a power station?
What form of energy
(a) goes into,
(b) comes out, of a generator
Copy and complete the following sentences…
Power stations use _____ to heat water and
change it into steam. Steam turns ____, which
spin large magnets. Magnets spinning inside a
coil of wire produce an ____ current.
Electric Fuels Turbines
5.
6.
What harm can power stations do to the
environment
How could you reduce this harm?
Rollercoasters
Rollercoaster Activity – Pass Criteria
This lesson…
• You have design the plans
for a rollercoaster.
• The rollercoaster
construction team need a
‘side view’ of your design.
• E.g.
You must include…
1. How the rollercoaster gets
up the fist slope.
What energy changes are
taking place here
2. What heights are the drops.
Why the heights of the
drops are different
3. What energy changes take
place as the rollercoaster
travels
What forms of energy are
Useful / wasted?
Plan…
• This lesson…
Draft (on one side of A4) show to Mr C
• Next lesson…
Final copy – once draft has been checked
Module 9 – Energy, Lesson 9
Monday, 13 April 2015
Gravitational Energy
Aims of lesson:
•
•
Know how to calculate the
energy of an ‘elevated’
object
Know how elevated
objects store energy
Starter Questions
1.
2.
3.
What is the energy
change as a roller coaster
goes down a slope?
As the rollercoaster goes
down the slope is any
other form of energy
produced?
How does a hydro-electric
power station use
gravitational energy?
Energy
Form of Energy
Light
Heat
Electrical
Kinetic
Chemical
Gravitational
Example
Diagram
Energy
Energy
Energy
Energy
Energy
Energy
Gravitational Energy
The amount of energy an object has depends on
three things…
•The mass of the object
•The height it is lifted
•The strength of gravity
Mass & Weight
The amount of ‘stuff’ in an object.
Mass always stays the same (kilograms)
Gravity (a force) pulls on objects (with mass). The force of
gravity on an object is its weight. (Newtons)
Mass:
Weight:
Weight = mass x gravity
(N)
=
(kg) x (N/kg)
1 kg
Mr Connett has a mass of 74kg. This
is the amount of stuff that makes
him.
Weight =
mass x gravity
=
74kg x 10 N/kg
=
740 N
On Earth gravity pulls on each
kilogram with a force of 10N
Calculation of Gravitational Energy
GPE (gravitational potential energy) = Mass x strength of gravity x height
GPE (gravitational potential energy) = Weight x height
Energy (or Work done)
= Force x distance
Questions…
(1)
(2)
(3)
(4)
A force of 100N drags an object 7 m. How much work is done?
An object, mass 3Kg is 6 m above the ground. How much potential
energy does it have?
A force of 6N is used to move an object 1 m. How much work has
been done?
(a) An object, mass 1kg is 10 m above the ground. How much
potential energy does it have this high up?
(b) How much energy will it have if is only 0.5 m above the
ground?
(c) How much energy will it have if it is at ground level?
(d) How much energy must it have lost if it falls from the original
height, in part a) to the ground?
Calculation of Gravitational Energy
GPE (gravitational potential energy) = Mass x strength of gravity x height
Questions…
(1)
(2)
An object, mass 3Kg is 6 m above the ground. How much potential
energy does it have?
(a) An object, mass 1kg is 10 m above the ground. How much
potential energy does it have this high up?
(b) How much energy will it have if is only 0.5 m above the
ground?
(c) How much energy will it have if it is at ground level?
(d) How much energy must it have lost if it falls from the original
height, in part a) to the ground?
Remember: Gravity = 10 N/kg
Calculation of Gravitational Energy
Energy (or Work done) = Force x distance
(joules)
Questions…
(1)
(2)
(3)
(4)
(newton)
(metres)
A force of 100N drags an object 7 m. How much work
is done?
A force of 6N is used to move an object 1 m. How
much work has been done?
A car is pushed a distance of 1000 m. The pushing
force is 300N, how much energy is used?
300 Joules of energy was used to move an object.
The force was 50N, how far was the object pushed?
Quantity Mass
…
Unit…
Strength Weight
of
Gravity
Height
gain
Energy
gain
1.
2.
3.
4.
5.
6.
What is the equation that links force, distance moved in the direction of
the force and work done?
What are the units of the above equation?
(a)
What are the units of work?
(b)
How much energy is transferred when a crane lifts a load of
5000N through a distance of 30m?
(c)
When does a force not do any work?
A car follows a lorry up a hill, which would have the most gravitational
energy at the top of the hill – explain your answer?
Sue weighs 500 newtons. She dives 4 metres into a swimming pool.
a) What is Sue's weight?
b) What is her change in height?
c) How much gravitational potential energy does she lose?
Work out the gravitational potential energy that these objects have:
a) A bird weighing 1 N, perched at the top of a 20 m high tower.
b) A football weighing 7 N, kicked 3 m up into the air.
As a bungy jumper falls through the air his gravitational potential
energy decreases.
a) Sketch a graph to show how his gravitational potential energy
changes into kinetic energy during his first fall.
Start your graph like this:
b) Where does the energy come from to make him bounce back
upwards?
1. What is the name of energy that ‘high
up’ objects have?
2. An object has a mass of 3kg, it is lifted
5m, how much energy does it have?
3. Mr C (mass 75kg) walks up some stairs
(10m). How much energy did he use?
4. What energy does a roller coaster have
(a) at the top of a slope
(b) at the bottom of a slope
5. As a roller coaster travels down a slope,
energy is wasted as H___ and S____.
6. At lunchtime Mr C, goes to Torridge Way
chippy. Does he have more or less
energy at the chip shop, compared to
school – why?
Mass & Weight
The amount of ‘stuff’ in an object.
Mass always stays the same (kilograms)
Gravity (a force) pulls on objects (with mass). The force of
gravity on an object is its weight. (Newtons)
Mass:
Weight:
Weight = mass x gravity
(N)
=
(kg) x (N/kg)
1 kg
Mr Connett has a mass of 74kg. This
is the amount of stuff that makes
him.
Weight =
mass x gravity
=
74kg x 10 N/kg
=
740 N
On Earth gravity pulls on each
kilogram with a force of 10N
Gravitational
Energy
GPE (gravitational potential energy) = Mass x strength of gravity x height
GPE (gravitational potential energy) = Weight x height
Recap…
• e.g.
• A car has a mass of 1200kg.
• It dirves up a hill 80 m high.
• GPE
= Mass x strength of gravity
= 1200kg x 10 N/kg
= 960000 Joules (J)
x height
x 80m
Gravitational
Energy
GPE (gravitational potential energy) = Mass x strength of gravity x height
GPE (gravitational potential energy) = Weight x height
At the top of the hill the car
has more gravitational
potential energy
At the bottom of the
hill the car has very
little GPE
Recap…
• e.g.
• A car has a mass of 1200kg.
• It dirves up a hill 80 m high.
• GPE
= Mass x strength of gravity
= 1200kg x 10 N/kg
= 960000 Joules (J)
x height
x 80m
1.
2.
3.
4.
5.
As a bungy jumper falls through the air his gravitational
potential energy decreases.
a) Sketch a graph to show how his gravitational potential energy
changes into kinetic energy during his first fall.
Start your graph like this:
b) Where does the energy come from to make him bounce back
upwards?
A weightlifter lifts a weight of 2250 N above his head.
It is lifted a height of 2m, how much work is done?
Mr C has a mass of 73kg
(a) What is his weight?
(b) If Mr C cycles up Efford lane, his height increases by 70m.
How much energy does Mr C use cycling up Efford Lane?
Calculate the gravitational potential energy of a mass of 3509kg
that has been lifted by a crane a distance of 20m.
The Earth’s gravitational field strength is 10 N/kg
Repeat question 2, but this time the crane is on the moon,
where the gravitational field strength is only 1.6 N/kg
Calculating Power…
EnergyUsed( J )
Power(Watts) 
Tim etaken( s)
Run or walk up stairs (from LSDH to maths floor) – Time taken = ……………s
My mass = ………. Kg
Energy used to run up stairs = mass (kg) x gravity (10 N/kg) x height (8.5m)
= ……… kg x
10 N/kg
= ……… J
Power = Energy used / Time taken
= …………. J / …………s
= …………… W (or Joules per second)
x
8.5m