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Copy of Bits of P1, P2 and P3 (OCR 21st Century)

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on 29 April 2014

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Transcript of Copy of Bits of P1, P2 and P3 (OCR 21st Century)

As the temperature rises, more water is evaporated from the surface of the oceans. Why will this further accelerate climate change?
The Carbon Cycle
Investigate how the changes in the atmosphere can change the Earth's climate
Determine the producers and absorbers of CO2 in the carbon cycle
Questions to be getting on with
Name two greenhouse gases
What's the difference between the ozone layer and greenhouse gases
What will happen as a result of an increase in greenhouse gases?
Draw your own simplified carbon cycle in your books
To farm intensively, trees are cut down and burnt. The ground is used to graze methane belching cows.

Name all of the ways that this increases the level of greenhouse gases in the atmosphere.
The Gulf Stream
The North Atlantic
Name three things that....
Produce greenhouse gases
Remove greenhouse gases
So why are we worried about climate change...?
The Gulf Stream and North Atlantic
drift are responsible for the mild climate in the UK.
After all we're on the same latitude as Canada
That video was created by the Australian Medical Students’ Association (AMSA). This is the representative body for Australian medical students.

Can and should we trust their video? Should we view it with cynicism?
The Effects of Climate Change
Outcomes - Discover the effects of
producing more carbon dioxide.
Three things you should have learnt by
the end of the lesson:
That a change in global temperatures will impact health as well as climate
The three greenhouse gases
How to evaluate scientific sources for accuracy and reliability
Developed countries like the UK and US are now trying to use more costly but more environmentally friendly energy production.

This is generally too expensive for poorer countries to build. Do we have a right to demand that they build renewable energy plants?
Radiation Carries
- Draw an analogue
and digital signal
- Learn benefits and negatives
of digital information

Things that are analogue have a continuous variation, rather than steps.

A good example is the dial on a radio.

Come up with two other examples.....

Things that are digital have very defined steps or states.

A good example is a light switch. It is either on or off.

Come up with two other examples.....

What's an analogue example of a light switch?
We transmit information using EM radiation. We use microwaves and radio waves for mobile phones and radio waves for radios and televisions.

To transmit and receive this information we need masts.
What kind of radiation is used for television?
What are the uses of Gamma Rays?
How do we work out the temperature of previous ages, using ice from the Artic?
Create a prezi which, explains:
The benefits and drawbacks of using digital and analogue signals
Explain how we filter out noise from digital and analogue signals
Explain why we use microwaves and radio waves for communication
Describe how an optical fibre works
Explain the benefits of using it
Bits and Bobs - The Final Wrap-up
Outcomes -

Cover the final parts of the P2 Syllabus
Learn about photons
Investigate storage of digital signals
Optical fibres transmit digital signals.

They are used in:
phone lines
some stereo cables
A couple of times every second the value of the analogue signal is read.

That value is turned into a digital signal and transmitted down the optical fibre.

In this way an analogue signal can be converted into a digital one.
Using total internal reflection, the same thing that enables you to see yourself in a window when you look at it sideways, beams of light are sent down the optical fibre.
To transmit the signal the pulse of light turns on (1) and off (0).

It's much like flashing a torch on and off to pass on a message.
Draw an optical fibre and explain how information is transmitted.
When we transmit information using electromagnetic waves, we use a carrier wave.

This is a wave with a regular frequency and amplitude.

To pass on the information, the signal is merged with the carrier wave. The resulting wave is then transmitted and separated out by the receiver.
We talk about light as a wave but in actual fact it is made up of little packets of waves.

These are called photons. They were discovered by Einstein early in the 20th Century.
Name two pieces of analogue data storage and two pieces of digital data storage.

Write down one benefit of digital data storage.
But how does a phone call become a digital signal?
Introduction to Energy
Determine primary and secondary energy sources
Explain why energy demand is increasing
A primary energy source is one that is found or occurs naturally.

Name three primary energy sources

A secondary energy source is created from a primary energy source.

They are easier to control and use than primary ones.

Electricity is a secondary energy source.
Energy is conserved and cannot be created nor destroyed.

It can only be transferred from one place to another.
What is the transfer of energy in a lamp?
Why do we call these last set primary energy sources?
What is this graph

Discuss in pairs

Why are all the bars going up?
Why will the increasing global population have an impact on our total energy use?

Why do African countries use
less electricity per person than
we do?
Why might we want to consider using wood burning power stations rather than coal, oil or gas?
Why might we want to consider using hydroelectric power stations rather than coal, oil or gas?
The supply of fossil fuels won't last forever
How much electricity do things use?
Use the equation to determine how much electricity an appliance uses
Read an electricity bill
Energy = Power x Time

Power is the rate at which something uses energy.

If Usain Bolt sprints 100m he can do it in 9.58 seconds.

If he walked the 100m it would take far longer.

It takes about the same amount of energy to travel 100m. By walking it however Usain is using far less energy every second.

The more energy used per second the more powerful something is
Energy (Joules) = Power (Watts) x Time (seconds)
Work out the electrical energy in Joules if I use a 2000W kettle for half an hour. You will need to use time in seconds for this equation.

The same energy in Wh (Watt Hours).

Which are the best units to use?
Energy is measured in Joules but this electricity meter has different units.

It says kWh or kilowatt hours. Why does it use this unit instead?
Electrical bill = Energy used x Cost of 1 kWh
(£) (kWh) (£/kWh)
Name 3 primary energy sources

Name 3 renewable energy sources

Name 3 energy sources that don't emit carbon dioxide
Sources of Energy
Use the efficiency equation
Explain how a power station works
Come up with 5 efficiency problems for your neighbour to solve.

Challenge your neighbour to draw a Sankey Diagram of your choosing.
Write a step by step account of how a power station works. Discuss in pairs and then do your best to put it in order.
When a wire passes through a magnetic field an electric current is induced in the wire.

The current can be strengthened by using more wire (a coil), a stronger magnet or by moving the wire more quickly.
Why do power stations produce alternating current?
Top fact - Over 90% of the energy lost in fossil fuel power stations is lost through the cooling towers
Explain simply how a simple generator produces a continuous electrical output using a coil of wire and a magnet. (a simple pencil-sketch diagram from top-left of p88 might be useful)
Explain what is meant by ‘alternating current, ac’ and how this is different to d.c.`
Describe three changes you can make to generate a bigger electrical output.
You are going to produce a powerpoint on one of the following types of electricity generation:
Fossil fuels
You need to include the following pieces of information:
How does it work? How does it create electricity?
How sustainable is it?
How widely used is it?
What conditions does it need, where can these power stations be built?
From Powerstation to Home
Explain how electricity travels
Describe why we need transformers (NOT robots in disguise)
Electricity to homes
Power = Current x Voltage

For the same power, as voltage increases then the current decreases.
Step-up transformers

These step-up voltage so that only a small current needs to flow along the wire.
Step-down transformers

These step-down voltage so that a larger current can flow along the wire.
Wegener and Continental drift turns up on EVERY exam, almost guaranteed. So do Global Warming and the Hole in the Ozone Layer. Make sure you know these!!!
Wegener was the scientist that came up with the idea of continental drift. He believed that tectonic plates were moving because:
He found similar fossils on very distance continental plates
Land masses appeared to fit together like a puzzle
The scientific community didn't believe him however because:
He was a meteorologist (weather specialist), not a geologist (rock specialist)
You can't observe the changes he claimed were taking place, you don't see tectonic plates moving
Geologists thought they had a solution to the 'fossils in different places' argument with the idea that there had been 'land bridges' crossing vast bodies of water
Answer these:
What is space?

What's our solar system called?

What is the solar system?

What are the names of the planets in it?
This is the Milky Way,
our galaxy
What is the Universe?
The Universe was formed 14 billion years ago....
That's 153,846,153 human lifetimes, a really stupidly big number
AStronomers have to measure distances without being able to use metre rules or tape measures.

How could you measure the size of the classroom whilst not moving from your seat?
Put these in size order:
Solar System
Introduction to P1

Know the order of the planets
Describe how we can measure vast distances
Lesson Objective - Organise the major events of the Universe in terms of how recent they are.
The history of the Universe
The evolution of man from the first walking creature took about 3 million years.
In comparison the Earth has been around for 4.5 billion years. That's 1000x longer.

In numbers we write it as 4,500,000,000 years!
The Universe has been around for 14 billion (14,000,000,000).

Try and work out the percentage of the Universe's existence that the Earth has been around for.....
Divide the age of the Earth by the age of the Universe.

Multiply this by 100.
To work it out...
The percentage of the Universe's life that humans have been around for...
Now try....
Lesson Objective - Describe the two methods used to measure the distances to the stars
Measuring the distances to the stars
Work in pairs to come up with as many ideas as you can
How could you measure the size of the classroom without leaving your seat?
The Brightness Method
The Parallax Method
Let me see your thumbs
Full transcript