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Stardate Friday 13 October 2006 Issue 204

It’s Friday 13th – welcome to all you paraskevidekatriaphobics. You what?  That’s fear of Friday 13th to you and me.  Don’t worry, there are plenty of little tricks to ward off bad luck, and we’ve peppered this week’s newsletter with them. Superstitious?  Us?  Never! We are scientists after all.  Now where did we put that rabbit’s foot…

The line-up this week:

  1. Mind-blowing Maths: Disappeared into thin air…?
  2. Activity of the Week: Green pennies
  3. Stump the Scientist: Milky eruption
  4. Mouses at the Ready for Flipsides
  5. Noticeboard: FYI
  6. Recommended websites of the week
  7. The Winners’ Enclosure
  8. Joke of the Week

1. Mind-blowing Maths
Here’s Ben Craven, one of our two resident math-magicians, to tell you something that will scramble your synapses.  This week he tells us that all that separates us from space is… thin air! Prove it Ben!

Stand on a mountaintop and look at another mountain 10 kilometres away. It doesn’t seem very far, and on a clear day it can seem startlingly close. But when you look at that other summit, you are looking through more air than if you look up at a star in space above your head.

But don’t books tell us that the Earth’s atmosphere is 30km thick, 100km thick, or even thicker?

Actually, it’s a matter of opinion where the atmosphere stops and space starts – the air just gets gradually thinner with altitude.  It’s more revealing to ask – how much air is there between us and space?

To do this, let’s ask how thick the atmosphere would be if it contained the same amount of air, but instead of fading away gradually, was at sea-level density all the way up to a point where it stopped and the near-vacuum of space started.

Air pressure at sea level is about 105 newtons per square metre. That is, if we take a column of air whose cross-section is 1 square metre, going right up into space, the air in that column will weigh 105 newtons.

Now weight is given by mass multiplied by g, the acceleration due to gravity. At sea level, g is 9.81 metres per second squared, declining only slightly through the thickness of the atmosphere. This means that the mass of the air column is about 10,500 kilograms. 

The density of air at sea level is about 1.2 kilograms per cubic metre, so 10,500 kilograms of air at this density would occupy 10,500/1.2 = 8500 cubic metres, roughly. So if our column of air were all at sea-level density, it – and therefore the atmosphere - would be only about 8 or 9 kilometres high.

That’s walking distance. This is all the air that is between us and space. This is all the air that has to take the carbon dioxide and other pollutants that we merrily churn out.

Not much, is it?

A pinch of salt over the shoulder - that should do the trick.  Oops sorry Mrs Miggins, didn’t see you there…
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2. Activity of the Week: Green pennies

You will need:

  • A saucer
  • Some paper towels
  • Vinegar
  • 3-5 pennies

What to do:

  1. Arrange the paper towels into a wad on your saucer.
  2. Pour enough vinegar into the saucer to cover the paper towel.
  3. Place the pennies on top of the wet paper towel and leave for a few hours.
  4. Encourage observations; look at both sides of the pennies. The tops of the pennies turn green and the bottoms of the pennies stay copper coloured.

What’s going on?

Vinegar is an acid that has the chemical name of 'acetic acid'. Part of this acid combines with the copper of the pennies to form a green coating that is composed of copper acetate. Oxygen must be present for this chemical reaction to occur. Oxygen comes from the air, and this is why the tops of the coins turn green but the bottoms do not.

All’s going well so far – touch wood.  Aaagh! A splinter…
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3. Stump the Scientist

Before we finally shut the dishwasher on last week’s debate the last word has to go to Peter Levitt 

“Re: plastic and ceramic plates

This has stirred my grey cells.

I think that thermal conductivity might be the real answer. To evaporate a given mass of water from the plates - assuming equal areas and plates at same temperature - will need the same quantity of heat for each plate.

So the rate of evaporation - the key to which plate feels wetter when removed from the dishwasher at a given time after it is switched off - will depend on the rate of heat transfer through the material. The thermal conductivity of ceramics is about 3 times that of thermoplastics so the process will go about 3 times quicker - hence the ceramic plate will feel drier after a given time.

I think the idea of 'retaining heat' is not helpful since everything loses heat to the surroundings as long as it is at a higher temperature. The thermal conductivity idea might also explains why plastic plates always feel cooler (in Simon Lampitt's argument) and John Marshall's point about the nature of the surface is also a likely contributing factor.

However - and in conclusion - as educators, shouldn't we be selling our energy guzzling and environmentally unfriendly dishwashers and getting back to hot water, elbow grease, dishcloths and tea towels!!”

Good point Peter.

So on to this week’s stumper…

Angela Pollard writes:

Making my coffee in the staff room the other morning, I added a spoonful of coffee granules to half a cup of hot milk, only to find that the milk erupted and splashed spectacularly out of the cup. I've since tried to repeat this 'success', with varying results. What was going on?

If you can help or if you have a burning question of your own then send us an email with STUMP THE SCIENTIST in the subject line to planet-science.news@nesta.org.uk

I’m looking over, a four-leaved clover – that I overlooked before …  tra la la. Oh. How lucky is it to tread in a cowpat?

4. Mouses at the Ready

Ooh how eerie – we’re talking about the new ultraviolet tattoos in the October issue of Flipside. It's a cosmic special, so UFOs, those ultraviolet tattoos (brilliant idea - you don't see them unless there's an ultra violet light on), Chinese robotics, how to tell if someone's lying, and reporting on your young person’s path to Olympic glory if they make a start now!

We’ve got FIVE copies to give away.  Simply send an email with your name and address, and the words FLIPSIDE in the subject line, to planet-science.news@nesta.org.uk.

If you want to know more about this fantastic mag then check out their site.

The draw will take place at 5pm on Wednesday 18th October.

Carrying rabbits’ dismembered limbs around for good luck is hardly very pc is it?  How did all that start anyhow? One source says that it’s not just any old foot.  More specifically it’s the left hind foot cut off a live rabbit shot with a silver bullet in a cemetery during a full moon on Friday the 13th. But they didn’t have any of those at Poundstretchers so we bought a horseshoe key-ring instead.
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Noticeboard

 

NESTA's speed networking event

From those lovely people who bring you Planet Science, another cordial invitation. Get Connected...

...and join NESTA's speed networking event.

Networking can unlock a whole world of opportunities - a chance to meet people who can open doors, share experiences and be a source of inspiration and advice. At this speed networking event you will meet 12 people in one hour - guaranteed.

Date: Friday 17th November
Time: Arrive to register 6.30pm, first whistle at 7pm
Venue: Dana Centre, 165 Queen's Gate, South Kensington, London, SW7 5HD

This event is free and being organised by NESTA as part of Enterprise Week. It is all about sharing knowledge and expertise, connecting people, and getting people talking. It will bring together a unique mix of entrepreneurs, educators and young people to share experiences, advice and create opportunities.

Drinks and nibbles? Absolutely!

If you feel it’s not quite your thing then please do pass this invite on to the staff member of your school whose street it might very much be up.

To register:
futureinnovators@nesta.org.uk
 

 

London 2012 has launched 'On Your Marks', a new online education resource.

On Your Marks! contains fact sheets, news articles and  cross-curricular teaching ideas including some on forces and healthy living.
 

 

Computer Science Writing Competition 2006/07

Inspire, inform and put the spotlight on computer science. There are prizes of up £1,000 on offer.

Computer science research impacts on all areas of modern life - from banking to healthcare and commerce to computer games. If you think you could write an article about how computer science research affects our lives then why not enter.

The competition is being organised by the Engineering and Physical Sciences Research Council in association with the British Computer Society, the Institute of Engineering and Technology and the Royal Academy of Engineering.
 

 

Engineering Grants: £4000 - £40,000

INGENIOUS - A grants programme to raise public awareness of engineering.
There are two levels of funding available, and Educators are one of the listed professions eligible to apply:

Activities and Development grants (£4,000 to £40,000)
Individual grants (up to £2,000)

For more info

Application deadline is Friday 19th January 2007.
 
 

Planet Science Quiz

There’s still time to enter our humerus October Quiz.  Answer the questions right and a magnificent ‘Skeletons in the Closet’ game could be yours and/or a selection of skelly themed tat and sweeties in time for Halloween. Tricks and Treats, see?!
 

 

Horrible Science Last Week

Roll up! Roll up! Our biggest giveaway yet has reached its last week, so only a week to go to win one of 10 brilliant science kits or one of 15 Measly Medicine Horrible Science Books.

The three ‘horrible’ multiple choice/guess questions may look bamboozling to the younger visitor, but judicious use of the Planet Science search facility will reveal that all the answers are in the quiz archive on the site. Hurry, Hurry, Hurry!
 


 

Vote for Scottish Science Hall of Fame

The National Library of  Scotland is currently developing a website feature called 'Scottish Science Hall of Fame' which will profile 10 figures from the past whose scientific discoveries or inventions have affected the way we live today. They want people to vote for the top 10 scientists to be included on the site, and would particularly like to encourage schools to take part in this.

Anyone can vote by following a link on the National Library website.

Voting closes at the end of October.
 

 

See a pin, pick it up and all day you’ll have good luck! Luckier still if you saw the pin before you trod on it in your BARE FEET.
 

6. Recommended Websites of the Week

Check out some cool new stuff to download on www.atomsclub.co.uk. Use your detective skills in the Cracking Codes activity sheets & play the Beetle Drive game - just in time for the new school year! 

BBC Science & Nature presents Supergoose.

– follow the action as ten geese take-off on an 8,000km migration from Ireland to Arctic Canada and back. Goodbye Douglas. Sob! We’ll never forget you.

Reader’s Recommended Website:

Another thumbs up for Doc Brown's Science Revision.

Martin Fletcher says “I have got all my key stage 3 teachers to use doc brown as part of our revision programme at the end of each topic test with years 7, 8 and 9. It is excellent”

Hello, it’s Jet the coal-black moggy from next door - nearly tripped me up there Jet, running across my path like that! Watch the road!!! Whoaaaa…
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Last week’s winner of the family place on the ‘Protons for Breakfast’ course was Su Bowerman of Chiswick. Well done!  Hope you enjoy it. Best with semi-skimmed…

A horseshoe. You can’t get much luckier than that. Unless you backed the horse that lost it in the 3.25 at Kempton Park…
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8. Joke of the Week

Two video funnies for you this week:

- Stop global warming
- Entrepreneurial cavemen

And if you can’t play videos, you’ll have to suffer this groansworthy one:

A man went to the doctor because he didn't feel well. "What do you eat?" asked the doctor.

"For breakfast I have a couple of red snooker balls, and at lunchtime I grab a black, a pink and two yellows. I have a brown with my tea in the afternoon, and then a blue and another pink for dinner."

"I know why you are not feeling well," exclaimed the doctor. "You're not getting enough greens."

Can you do any better? You know where we are: planet-science.news@nesta.org.uk Don’t forget to put JOKES in the subject line.
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That’s all for this week but remember – if you’ve got anything to add then drop us a line: planet-science.news@nesta.org.uk.We’re open to contributions 24/7.

Have a great week.

If you would like to view the Planet Science Newsletter Archive click: http://www.planet-science.com/about_sy/news/ps_index.html You can read back issues of Wired-Up for younger teens here: http://www.planet-science.com/wired/wiredNL/archive/ Or you can read back issues of Hay-Wire for Under 10s: http://www.planet-science.com/wired/haywired/archive/

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