Protons for Breakfast Week 1: Electricity November 2009

Protons for Breakfast

Week 1: Electricity

November 2009

In the event of an alarm sounding…

Toilets…

Parents and children…

The plan for the evening…

7:00 p.m. to

7:59 p.m.

8:00 p.m.to

8:29 p.m.

Walkabout 8:59 p.m.to

9:00 p.m.

Feedback

Talk

8:30 p.m.to

8:59 p.m.

More talk

Who is helping? • Jonathan Pearce• Laurie Winkless• Lindsay Chapman• Mateusz Szymanski• Matthew Tedaldi• Clive Scoggins• Neelaksh Sadhoo• Paul Carroll• Peter Quested• Peter Woolliams• Piers de Lavison• Rainer Winkler• Richard Gilham• Robin Underwood• Ruth Montgomery• Sharmila Hanson• Stephanie Bell• Tim Burnitt

• Amanda Law• Andrew Hanson• Arzu Arinc• Averil Horton• Bufa Zhang• Deborah Lea• Emma Woolliams• Gianluca Memoli• Heather Browning• Jacquie Elkin• James Miall• Jeff Flowers• Jenny Wilkinson• Jian Wang• Joanna Lee• John Makepeace• John Mountford

Acknowledgements

• NPL:– The National Physical Laboratory

• Serco:– Manage NPL on behalf of the BIS

• Amey:– Who set out the rooms

• Baxter Storey:– Who do the tea & biscuits

Who is Michael de Podesta?

Age 49:• Lecturer in Physics at

Birkbeck College and University College London for 13 years

• Scientist at NPL for 9 years.

• Building the most accurate thermometer ever.

• Married with two sons (aged 11 & 13)

• Keen on Water Rockets• MBE!

MBE!

Why are you here?

A selection of your reasons for attending…• My son and I are very interested in learning about science• To improve my understanding and my teaching of Physics.• I am interested in all aspects of science and how it affects

us and everything around us.• To try to understand more about the world (more than I can

take in from reading).. • I love Physics! I am very interested in Physics as a potential

career.• It looks very interesting and I want to share the experience

with my daughter who will then be in Year 8.• Poor Science lessons at my grammar school. Teachers

seemed more concerned with neat writing• Near total ignorance. No Physics since 1944

Why am I here?

I am here because I believe …

Science is humanity’s greatest achievement

But there is a problem about how we, as citizens, relate to science…

The image of science:1Mad Muppets top cult science poll

Dr Honeydew is known the world over for his disastrous research at Muppet Labs,

"where the future is being made today".

His experiments invariably go awry, with poor old Beaker usually being blown to bits or electrocuted. BBC 6/9/2004

The image of science:2Science Gone Wrong

The final touch… What! BANG!

Alex Noble (Age 9)

The image of science:3An un-scientific experiment

Scientist

……… Scientist

In contrast…

• A room full of people who want to learn about science• Helped by volunteers • In a world where ignorance makes us powerless

Tonight’s talk

• The scale and size of the Universe – Its very big, but full of very small things

• The electric force– It dominates every physical phenomenon on our scale.

• How the force works– Electric particles– Electric field

• Light– Waves in the Electric field

Tonight’s talk

The scale and size of the Universe

Or

‘How not to be boggled’

The imperceptible and the vast (1)

As human beings we can judge:• temperatures close to ‘normal’

• weights greater than a gram up to around 1000 kilograms

• distances greater than a millimetre or less than a few kilometres.

• times greater than a second or less than a fraction of a lifetime.


As human beings we cannot judge:• temperatures more a few degrees away from ‘normal’

• Such temperatures just feel ‘very hot’ or ‘very cold’• weights beyond a few tonnes or less than a gram

• Such weights seem either stupendously heavy or negligible• distances less than a millimetre or greater than a few kilometres.

• Such distances are too tiny or too far to perceive directly• times less than a second or more than a fraction of a lifetime.

• Such times are too small or too long for us to appreciate


Quantities and qualities that extend beyond our ability to perceive them often seem:

imperceptible or vast

? ?


• Measurement: Quantitative comparison• Measuring instruments extend our senses

• Telescopes & Microscopes, • Weighing machines,• Devices sensitive to electricity & light, • Clocks

• NPL• Enables people to trust measurements


• We can be unaware of things because they are– Too small– Too large– Change too quickly– Change too slowly

• Science can help us to quantitatively assess matters we commonly perceive as imperceptible or vast

– But these things can still induce a feeling of being ‘boggled’

Diameter:

12,800 km

Deepest hole: 10 km

Atmosphere: 10 km

The Planet Earth

Photo Credit: NASA

The Moon

Diameter

Earth:

12,800 km

Moon:

3476 km

Photo Credit: NASA

The Sun

Diameter: 1,390,800 km

Photo Credit: NASA

Powers of Ten

I hope that you are now a little unsettled and ready to go on a 9 minute journey to see how the world looks at different levels of ‘fantasy magnification’

Photo Credit: Powers of 10

Very Very Small

Very Very

Large

Powers of Ten (1)

1 metre

1000 m

1000000 m

1000000000 m

1000000000000 m

0.001 m

0.000001 m

0.000000001 m

Can you see the problem with very small and very large numbers?

Powers of Ten (2)

Very Very Small

Very Very

Large

1

1000103

106

109

1012

1015

1000000

0.00110-3

10-60.000001 1018 1024 1030 1036

1021 1027 103310-15 10-9

10-18 10-12

100

Powers of Ten (3)

Very Very Small

Very Very

Large

1 metre

103

106

109

1012

101510-3

10-6 1018 1024 1030 1036

1021 1027 103310-15 10-9

10-18 10-12 1012

1000000000000 m

0.000000000001 m

Powers of Ten Length Scale in metres

Very Very

Large103

106

109

1012

101510-3

10-6 1018 1024 1030 1036

1021 1027 103310-15 10-9

10-18 10-12

?Very Very Small

100

Human Relationships

Atoms & molecules

Nucleiof atoms

Current estimate of the size of the

universe

Nearest StarLight YearTallest MountainNanotechnology

Distance to the Sun

Diameter of the Earth

Diameter of a hair

MicrobesViruses

Quarks

Powers of Ten Length Scale in metres

103

106

109

1012

101510-3

10-6 1018 1024 1030 1036

1021 1027 103310-15 10-9

10-18 10-12 100

Human Relationships

Distance to the Sun

Atoms & molecules

Nucleiof atoms

Current estimate of the size of the

universe

Nearest StarLight YearTallest MountainNanotechnology


Diameter of a hair

MicrobesViruses

Quarks

Powers of Ten Global Warming

Very Very

Large

100

103

106

109

1012

101510-3

10-6 1018 1024 1030 1036

1021 1027 103310-15 10-9

10-18 10-12

Very Very Small

Human Relationships

The phenomenon of global warming involves physical processes with

length scales spanning 20 powers of 10!

Distance to the Sun

Tallest Mountain


Atoms & molecules

Microbes

Powers of Ten Nuclear Power

Very Very

Large

100

103

106

109

1012

101510-3

10-6 1018 1024 1030 1036

1021 1027 103310-15 10-9

10-18 10-12

Very Very Small

Human Relationships

Tallest Mountain

The issues surrounding nuclear power involve

physical processes with length scales spanning 25

powers of 10!

Nucleiof atoms

Distance to the Sun


Atoms & molecules

Microbes

Powers of Ten (time)Time scale in seconds

Very Very short

Very Very Long

100

103

106

109

1012

101510-3

10-6 1018 1024

102110-15 10-9

10-18 10-12

Time for a molecule to jiggle once

Light wave wiggles once

Earthmoves once

around the Sun

Estimated time since the big bang

Age of the EarthEnd of last ice age

Lifetime of a Civilisation

A human lifetime

Fastest response of human

eyeSound

travels 1 metre

1 second

The Universe – Its very big, but full of very small things

The imperceptible and the vast

? ?

Electricity

Electricity

Now we can begin…

Electromagnetic waves

Atoms

Heat

Electricity

Electricity

Eeeee - lec- tric-ity

Electricity

Some experiments…

Lets take a look at some odd phenomena…

• A balloon and a piece of paper

Lets take a look at some odd phenomena…

• If I balance my glasses carefully…

Even a sausage…

• Sausages…

…its everything…

The balloon affects anything and everything nearby

To understand this, we need to understand • what matter is made of, and • how this ‘influence’ is communicated across ‘space’

A simple scientific instrument: The gold leaf electroscope

• Scientists can develop instruments to measure the relative strengths of the ‘electric influence’

• Based on the same effect we saw with bits of paper

The Van de Graaff Generator

• Scientists can develop machines to automate and amplify the ‘rubbing’ process with the balloon

Photo Credits: Katherine Robinson and MIT


It is not important to understand how a Van de Graaff generator works

PictureCredits: http://www.ikp.uni-koeln.de/~3T/tandem-prinzip1.htmlhttp://science.howstuffworks.com/vdg1.htm


It is not important to

understand how a Van de Graaff generator works

The Wimshurst Machine

Sorry: I cannot easily explain how a Wimshurst Machine works!

Photo Credits: Wikipedia and http://www.coe.ufrj.br/~acmq/electrostatic.html

Electrostatic Generators

• People have been doing this for a long time…

Photo Credits: http://www.ikp.uni-koeln.de/~3T/tandem-prinzip1.html

Conclusion…

Electricity is present inside ALL matter

Its ‘influence’ can be communicated

across ‘empty’ space

Not Stuff • the gaps in

between matter• fields

Stuff • matter

How do we describe the world?

How do we describe the world?

Not Stuff (Fields)• Fields

• Gravitational• Electroweak• Strong

• Extend throughout space

Stuff (Particles)• Atoms

• Electrons• Neutrons• Protons

• Very small

We need to know about both particles and fields

Two different kinds of physical entity

The electrical nature of matter

Particle

with electric charge

Particle


Interact by meansof an electric field

Tonight’s talk…(3)


• The electric force– It affects everything




• Electric charge is a fundamental property of electrons and protons.

• Two types of charge (+ and -)• If particles have the same sign of electric charge they repel• If particles have different signs of electric charge they attract• The forces (attractive or repulsive) get weaker as the particles get

further apart.


• Electric charge is a fundamental property of electrons and protons.

• Two types of charge (+ and -)• If particles have the same sign of electric charge they repel• If particles have different signs of electric charge they attract• The forces (attractive or repulsive) get weaker as the particles get

further apart.

How it all fits together…

Electromagnetic waves

Atoms

Heat

Electricity

Atoms

Atoms

Protons, neutrons and electrons normally exist inside atoms

Atoms are small• Think of a millimetre

Atoms

1 mm

0.1 mm0.01 mm0.001 mm

• Atoms are roughly 10,000 times smaller than this…

Atoms

• There are VAST numbers of atoms in everything.– In just a handful of anything there are about the

same number of atoms as there are grains of sand on all the beaches and deserts on Earth combined

Photo Credit: http://www.morguefile.com ID = 104101


AtomsInternal Structure

How are atoms made?

proton

Interact by the short range ‘strong’ force – not electrical

Electrical Repulsion

How are atoms made?

Atoms (4)

Electrons• ‘orbit’ around the outside of an atom• very light• possess a property called electric charge

Nucleus• occupies the centre• very tiny and very heavy• protons have a property called electric charge• neutrons have no electric charge

How are atoms made?

• Nuclei (+) attract electrons (-) until the atom as a whole is neutral• The electrons repel each other

– They try to get as far away from each other as they can, a– and as near to the nucleus as they can


ChemistryAtoms, Elements & Molecules

AtomsThe Periodic Table

• Atoms with up to about 82 protons can be stable.• A material made up of a single type of atom is called an element

D:\CURRENT PROTONS Local Folder\Presentations\PfB10\PfB10 Week 1\elements-p.swf

D:\CURRENT PROTONS Local Folder\Presentations\PfB10\PfB10 Week 1\elements-p.swf

H

Atoms& Molecules

H2

N

N

• A molecule is a collection of atoms stuck together electrically.

H

H

0

H20

H

N2


Solids

Atoms (3)

• Atoms can be imaged on a surface

Photo Credit: Patrick Joseph Franks: NPL


• In ‘normal’ matter, there are equal quantities of positive and negative charge so that there is no attraction or repulsion of objects.

Object 1

Object 2


Mechanical Properties

Atoms and mechanics(9)

• Whenever two materials touch, the forces between them are the forces between the outer (valence) electrons

• All mechanical forces are actually electrical in nature

Object 1

Object 2


Conductors and Insulators

Atoms in solids (8)

Solids are made up out of lots atoms very close together.

– If the electrons can’t move easily from atom to atom: • The material is called an insulator

– If the electrons can move easily from atom to atom: • The material is called a conductor


How the balloon affected the paper…

Odd phenomena…


Odd phenomena…



How is the electrical force transmitted from one charged

particle to another?

How do charged particles interact?

It’s a three-step process…

Particle


Particle


Interact by meansof an electric field

…but the steps happen very quickly

The nature of interactions (1)

Analogy with water level and water waves

Tonight’s talk…(4)


• The electric force– It affects everything.



Summary

• Physics concepts span vast ranges of mass, length and time.

• The universe has two kinds of objects in it: Matter and Fields

• All matter (on Earth) is made of atoms which interact electrically.

• In matter as we normally experience it, there are equal amounts of the two types of electric charge and their effects cancel

• If we add or remove some particles with electric charge from matter then we can see the electrical effects.

Homework?

Homework

• Activity: Remember when you have your breakfast that you are eating protons and neutrons coated with tasty electrons.

• Research: What is the ‘frequency’ of your favourite radio station? Don’t just get the number (98.9, 198 etc.) get the units as well! They should be in – Hertz– Kilohertz– Megahertz

One minute feedback

• On the back of your handouts!• Rip off the last sheet• Please write down what is in on your mind RIGHT NOW!

– A question? OK– A comment? OK– A surprising thought in your mind? I’d love to hear it!

On-line Resources

• www.protonsforbreakfast.org –This PowerPoint ™ presentation.–Handouts as a pdf file

• blog.protonsforbreakfast.org –Me going on about things

• links.protonsforbreakfast.org –Links to other sites & resources

http://www.protonsforbreakfast.org/

http://www.protonsforbreakfast.org/

http://blog.protonsforbreakfast.org/

http://blog.protonsforbreakfast.org/

http://links.protonsforbreakfast.org/

http://links.protonsforbreakfast.org/

See you next week!

Don’t forget your pencils and badges!

GoodnightGoodnight

GoodnightGoodnight

Documents

Protons for Breakfast Week 1: Electricity November 2009