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Energy & Resources:

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).”

9

What is energy’?

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

It’s easy to go wrong

  1. The moving pencil uses kinetic energy.’ (QCA)

  2. 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)

  3. Carbonaceous matter is converted to heat or other forms of

energy.’ (Physics World)

  1. Energy makes things happen.’ (ASE Big Ideas)

  2. The bulb lights because energy flows from the battery to the bulb.’ (Sophie, Year 9)

12

It’s easy to go wrong II

  • 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

Why these are wrong…

  • 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…

Vis Viva becomes energy” in 1802

The product of the mass of a body into the square of its velocity may properly be termed its energy.”

Phlogiston/Caloric/Work-Heat

Forms…

Forms of 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.”

From BBC Bitesize…

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22/06/2020 20

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Energy today

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.

22

How does a microphone work?

  1. - A microphone converts sound energy to electrical energy.

  2. - A microphone converts a sound wave into an electrical signal.

Energy stores & pathways

http://supportingphysicsteaching.net/En02TA.html

  1. 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.

  2. 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).

  3. 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.

A circus of energy experiments

Working with someone from another school…

…do as many experiments as you can. ~30 minutes

Thoughts?

Students often confuse …

39

Mechanical energy

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

Energy efficiency

product labelling

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Thermal transfers

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.

UK Energy futures

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’

A balance sheet

Energy consumed

Energy produced

Cars

Wind

Planes

Solar

Heating and cooling

Hydroelectricity

Lighting

Offshore wind

Gadgets

Waves

Food and farming

Tide

Stuff — materials from cradle to grave

Geothermal

Public services

Fossil fuels - coal, oil and gas

Energy industries

Nuclear

Ben Goldacre, Bad science

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.’

In the science classroom?

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

Useful websites

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/

https://www.talkphysics.org/groups/exeter-iop-

network-meetings/

Resources

Energy Resources is about ways of generating energy

Investigations;

Peltier

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