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1983
Forms -> Stores
Why & how teach energy?
In small groups, discuss:
Why and how has energy been taught at KS3/4?
What do students gain from it?
Is this useful for further studies?
I’ll ask for your thoughts in…
5 minutes
8
What is ‘energy’?
“The property of matter and radiation which is manifest as a capacity to perform work (such as causing motion or the interaction of molecules).”
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‘It is not a description of a mechanism, or anything concrete; it is just a strange fact that we can calculate some number and when we finish watching nature go through her tricks and calculate the number again, it is the same.’
Richard Feynman
‘The moving pencil uses kinetic energy.’ (QCA)
‘The steam [from a volcano vent] is converted into energy and transported to Europe via a 1,200-mile sea-floor cable.’ (a London newspaper)
’Carbonaceous matter is converted to heat or other forms of
energy.’ (Physics World)
‘Energy makes things happen.’ (ASE Big Ideas)
‘The bulb lights because energy flows from the battery to the bulb.’ (Sophie, Year 9)
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The useful energy input of a food processor is electrical energy and its useful energy output is kinetic
Some of the energy released by the Sun is converted into electrical energy
A microphone converts sound energy to electrical energy
Machines are noisy. They transfer energy and some of the energy is transformed into sound
Green plants capture light energy and use it to grow
The cells in animals and plants all use energy for the jobs they do.
Chemical energy from hydrocarbon fuel is converted into motion
treat energy as a substance (when it is a calculation tool)
are ambiguous and inconsistent
Use energy like phlogiston
give causal powers to energy
Teaching challenges…
“The product of the mass of a body into the square of its velocity may properly be termed its energy.”
You should be able to recognise the main types of energy. One way to remember the different kinds of energy is to learn this sentence:
Most Kids Hate Learning GCSE Energy Names
Each capital letter is the first letter in the name of a type of energy.”
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How many Mars bars would I need to climb a mountain?
How much coal/oil do I use in a day?
Will UK electricity production match peak demand? (Aside)
…requires calculation.
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- A microphone converts sound energy to electrical energy.
- A microphone converts a sound wave into an electrical signal.
Observation: the spring unwinds and lifts the masses. The spring may have got a little warmer — though it would be hard to notice that in a small system.
Discussion/Explanation: the coiled spring exerts an upwards force on the masses that is bigger than their weight. Therefore there is a net upwards force and they accelerate. They quickly reach a steady speed and the spring does work to raise them. It also does work against friction and air resistance and raises the temperature of the mechanism and surrounding air (ever so slightly).
Energy analysis:
Start point: there is an elastic store associated with the wound spring;
End point: there is a gravitational store associated with the masses. This store has filled as the elastic store has emptied. Some internal stores have also filled a little.
Working with someone from another school…
…do as many experiments as you can. ~30 minutes
Thoughts?
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For an object starting from rest,
impulse=force´ time=mv
Work done
W =F´ displacement =F´ (average velocity´ time)
W =Ft´ v =mv(v)=mv2
2 2 2
Therefore no surprise that, in some mechanical systems,
mgh+mv2 =constant 2
e.g. roller coaster, or pendulum
product labelling
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Energy transfer from one store to another because of a temperature difference. conduction: Ek transferred from atom to atom
convection: bulk movement of a fluid caused by localised thermal expansion and hence differences of density in the fluid. radiation: warm body emits a continuous spectrum of electromagnetic radiation, with peak frequency related to absolute temperature.
David MacKay, Sustainable energy – without the hot air
Concerns about UK energy policy:
Fossil fuels are a finite resource • Security of energy supply
for the UK population and the economy
not reliant on foreign energy sources — diversified sources mean more robust
CO2 and climate change
‘Numbers, not adjectives’
| Energy consumed |
|
|---|---|
| Cars |
|
| Planes |
|
| Heating and cooling |
|
| Lighting |
|
| Gadgets |
|
| Food and farming |
|
| Stuff — materials from cradle to grave |
|
| Public services |
|
| Energy industries |
|
12 December 2009
Climate change? Well, we’ll be dead by then
’Zombie arguments survive, immortal and resistant to all refutation, because they do not live or die by the normal standards of mortal argument.’
Carefully structured discussions to develop skill in policy-related argument, based on
science, if possible including quantitative estimates
social values
a basic understanding of how collective (social, political and economic) decisions are made in the UK
… simplifying the breadth and depth of science to match pupils’ age and ability
Climateprediction.net follow links Support -> Schools
Realclimate.org climate scientists’ blog and archive
Google Earth v5 time series images show impact of climate change UK Energy Flows comprehensive Sankey diagram published every 3 years
The Guardian pages on Climate change - plus related
Environment pages … and weblinks
http://supportingphysicsteaching.net/EnHome.html
https://www.talkphysics.org/ https://www.talkphysics.org/groups/
“Energy Resources” is about ways of generating energy…
