Wednesday 30 July 2008

Tanneries and water - meandering through Morocco

Morocco is a hot, dry place. We were lucky enough to visit the town of Marrakech last week, and apart from being stunning to look at, it was 40 degrees and chaotic! This latest post is not meant to be a travel blog - there are plenty of them out there - but instead we are going to take a look at some of the science from this most recent trip abroad.


To work in a tannery in Marrakech is to work under some of the harshest working conditions there are. Not only are you exposed to the blazing sun, but you are are soaked in blood, animal bodily fluids and parts, pigeon poo, and get paid appallingly.

But there is some science to the ancient Moroccan tannery tradition.

Legend has it that the tanners are descended from demons who lived under a black king. As they didn't obey his rules, they were condemned to work in the tanneries. They use hundreds of concrete vats to process animal skins which are bought locally in the souks. The skins (mainly sheep and goat although cow and camel are sometimes used - lions are no longer used as they were hunted to extinction in the region around 1900) are treated far differently to the way leather is treated in other parts of the world as the process clings to its ancient traditions. Hair and flesh are removed by soaking the skins in quicklime (Calcium Oxide formed when limestone - calcium carbonate - decomposes) and water. After this, the skins are placed in a vat of water and blood, then separated and rung out, before being coloured using a few natural products:
  • Pomegranate for yellow;
  • Olive oil for shininess;
  • Bark for various colours, presumably brown;
  • Saffron for golden yellow;
  • Henna for red/orange;
  • Poppy for many other colours including white, pink, yellow, orange, red and blue.
The skins are stretched out and left to dry for over 20 days in little piles that look rancid. Pigeon poo is used to soften the leather, and if anyone knows why, I would love to know. Presumably the poo is slightly acidic. Pigeon poo has actually been reported to be quite dangerous, with people almost dying after ingesting it. The poo adds to the smell of the place, with there being large pigeon coups near the top in which you could wade knee deep in the brown-smelly stuff.

Our guide, apart from ripping us off ridiculously, did give us some mint to hold under our noses to mask the smell.

If you want to be a tanner, you need to be born into it, and only men are allowed. Many suffer from arthritis and are forced into an early retirement. And it has been reported that in Bangladesh, half a million people are at risk of serious health issues due to their tanneries emitting toxic chemicals such as sulphuric acid. Not a place I would like to work.


Morocco has a massive water problem. It rains about a third of that in Canberra, Australia, which is considered in severe drought. The average rainfall in a summer month is 3 mm, and there are increasing demands on the scare water-supply by a massive push to increase tourism and reduced rain-fall, presumably due to global warming. The period in which crops woudl grow in the 1960s was about 180 days per year. Now it is 110, and most of the country still live off the land. Add to this food shortages and there will be a problem in the years to come.

It has not always been this way. When Marrakesh was originally settled by the Almoravids, who had lived in the desert all their history, water management was done well. The Almoravids built massive underground piping systems called khettaras which brought water from melted snow from the Atlas Mountains, a few hundred kilometers from Marrakech. It was quite an engineering project, but unfortunately western irrigation techniques, developed in places where there is lots of water, are now being used and water is running out. There are still magnificent oases in Marrakech, such as the Palmeraie and the Majorelle Gardens, but these are irrigated using modern methods.

I took my recording gear to Marrakech, so listen up to the podcast here. You will also here some commentary from the local lads on Australia, east and west coast America, and north and south England, and some of the sounds of Marrakech.

Listen here:

More of my Marrakech photos can be found on my flickr site.

Monday 28 July 2008

Cocoa Condoms

Not too long ago we sort to find out whether or not you can recycle condoms, and didn't reach a conclusion. However, there has been one recent development in this area, with the condom manufacturer Condomi releasing condoms that are slightly higher up the ethical stakes.

Condoms are made from latex, which comes from the tropical rubber tree Hevea brasiliensis. Liquid latex, a dispersion of rubber particles (30%) in water (70%), lies between the bark and wood and is collected by slashing through the bark and allowing the latex to flow out. Ammonia is added to counter the acid production of waste products from the bacteria that naturally feed on the latex and cause it to curdle.

The liquid latex is centrifuged to concentrate the rubber particles so that it is 60% solid rubber. Other chemicals including an antioxidant, a sulfur-based vulcanizing agent, and a vulcanizing accelerator, are added to increase both the rate and extent of cross-linking in the latex compound during vulcanization - a process in which polymer molecules are cross-linked by sulfur atoms or carbon-carbon bonds under high heat. This makes the latex harder and more durable.

This is where there is some ethical debate. The manufacture of condoms usually involves casein, a phosphoprotein that occurs in milk and cheese and so is from cows and not vegan friendly. Casein is added at this stage to toughen up the latex. Condomi have replaced casein with cocoa powder. It is thought that these condoms might be a tiny bit weaker.

I'm not sure which option is the best for the planet as the latex produced is still largely not biodegradable, but it's good to see that the best brains on the planet have made life a bit easier for a couple of vegans. I always figured there was some connection between sex and chocolate...

Friday 18 July 2008

Who is your favourite fictional scientist?

Who is your favourite fictional scientist? I've come up with my top 14 covering my favourites from my formative years, including Doc Emmette Brown and his flux capacitor, the parapsychology-studying ghostbusters and the crazy muppet scientists Beaker and Honeydew.

Have a vote in the poll and once we get enough responses, we'll close it off and write detailed profiles of those scientists who top the list.

If you can't see the poll (perhaps you are viewing in a feed reader that doesn't like flash), then follow this link: View Poll. Or check out the poll in the right sidebar of our homepage.

To get you in the mood, have a look at Forbes Magazine's Top 15 richest fictional characters, topped by Scrooge McDuck. This list features two characters who are arguably scientists - Tony Stark (from Iron Man) and Monty Burns (from The Simpsons). But I prefer to classify them as businessmen who work in scientific industry.

If we have missed anyone off this list, then please leave a comment.

Thursday 17 July 2008

Run away and join the circus - the science circus that is

Good looking science types

Interested in science communication? Love travelling? Then the Science Circus might be for you.

If you are a recent science or technology graduate and enjoy science communication, then you can earn a prestigious Graduate Diploma from ANU and travel Australia communicating science in cities, towns, outback stations, indigenous communities, schools, nursing homes, just about everywhere around Australia. Your HECS is paid for, and you get a living allowance.

I did the course in 2001 and it was fantastic, although judging from the picture above, and with all due respect to my year, it looks like the students have got better looking...

Not only have I now seen places in Australia that barely anyone gets to see, but I had a ball and made contacts in science communication fields. Plus, you are on tour much of the year and believe it or not, when you aren't, Canberra is a pretty good place to live.

Applications are due Friday 29 August 2008 - see the circus website, or this flyer, for more information.

For my reflections on my 2001 year, see my Science Circus flickr photo set and this rather silly Mr Science story - if you're game, listen to the podcast of that episode to hear me sing...

Wednesday 9 July 2008

Science Podcasters

I am happy to announce that The Mr Science Show has joined up with, a fledgling organisation for supporting and promoting science podcasts. It was started by Ginger Campbell, MD host of the Brain Science Podcast. The purpose of this website is to create a site where people can find high quality science podcasts about a wide variety of fields. It offers science podcasters a place to post announcements, show notes and links back to their websites and content. This is not a directory or hosting site. Our main motivation is a spirit of mutual support. We all believe in the importance of using podcasting as a tool to communicate science to a broader audience. We have chosen the blog format in recognition of the fact that sites with content that is constantly updated is also more attractive to search engines. The more content we post on this site, the more we will help all the shows on the site to get the recognition they deserve.

So get over and check out

Tuesday 8 July 2008

The 118118 Challenge

118118 is a directory enquiries phone number in the UK that has recently expanded to "answer any question you put to us, no matter how big or small."

So we thought we might test them out with some of the unsolved questions from our show, and then some maths.

Listen here, with the voice of 118118 played by the AT&T Text-to-Speech synthesiser.

Marc: Can you recycle condoms?
118118: In general, condoms are made of latex and are not recyclable. It is probably better to dispose of your used condoms in the rubbish. Thank you!
Verdict: Pretty much what we came up with too. To read more about recycling condoms, see the Mr Science article Recycling Condoms.

Marc: How many colours to do you need to colour a political map of the world such that no two bordering countries are the same colour?
118118: Four colour theorem: any plan separated into regions, the regions may be coloured using 4 colours in such a way that no 2 adjacent regions receive the same.
Verdict: Pretty good. The four colour theorem is correct, although it is just a theorem and so no one has conclusively proven that you only need 4 colours to colour the map. See the Plus article The origins of proof IV: The philosophy of proof.

Marc: Is there a formula for solving quintic equations, like there is for quadratic equations?
118118: There is no formula for general quintic equations over the rationals in terms of radicals. Some can be solved by factorising into radicals. Thank you!
Verdict: Correct. For more on the quintic, see the Plus article The equation that couldn't be solved.

Marc: Is the Mandelbrot set locally connected?
118118: The Mandelbrot set is a set of points in the complex plane. It is a compact set, contained in the closed disk of radius 2 around the origin. Thanks!
Verdict: Well, that's correct but not an answer. That the Mandelbrot set is locally connected is an outstanding conjecture. To read more about the Mandelbrot set, see the Plus article Unveiling the Mandelbrot set.

Then I got my Plus co-editor Marianne involved, and she was less forgiving...

Marianne: Can any even number bigger than two be written as the sum of two primes?
118118: Every even number bigger than 2 can be written as a sum of two
primes. Thank you.
Marianne: But that's wrong!
118118: 2 is the only even prime.
Marianne: But that's got nothing to do with the question.
118118: Every even number bigger than 2 can be written as a sum of two primes.
Marianne: Still wrong.
118118: No charge. Please direct any questions to our customer service
Verdict: It was a bit harsh asking 118118 an unproven conjecture. The Goldbach conjecture postulates that all even number greater than 4 can be written as the sum of two odd primes. To read more about the Goldbach conjecture, see the Plus article Mathematical mysteries: the Goldbach conjecture.

Finally, a couple of big questions.

: Can science disprove God?
118118: It's a personal decision for you to make. Everything was "created", therefore decide if you believe it was by someone, some being or a metaphysical force.
Verdict: Nice answer!

And an even bigger one...

Should you have sex the night before a big sporting event? (see map)

Yes - Good for your performance:
No - Bad for your performance:
I'll take it when I can get it:
Only if you're married:
Makes absolutely no difference to your performance:
Total Votes: 199
Powered by Blog Flux Polls

Marc: Should you have sex before sport?
118118: Various studies have been carried out to examine the possibility that intercourse before a sporting event drains an athlete of their physical ability.
Verdict: Well, not an answer. So let us turn to readers of this site, and as you can see, 32% of voters say sex before sport is good for your performance and 24% will take it when they can get it, whilst 25% think it is bad for performance and 15% think it makes no difference. Only 5% thought you should be married. So from our poll, you definitely should have sex before sport, even just to get it when you can.

Listen here:

Wednesday 2 July 2008

Pi appears in crop circle, Mr Science appears in cliff face

If we are to believe the latest signs from outer space, the local aliens are keen mathematicians.

A new crop circle appeared on the 1st of June this year in a barley field near Barbury Castle in Wiltshire, England, measuring 150 feet in diameter and correctly representing the first 10 digits of the irrational constant pi.

If you look at figure, you will notice that the grooves in the circle spiral outwards with steps at various points along the way. You can see that these steps occur at particular angles — the circle is divided into 10 equal segments of 36 degrees each. Starting at the centre, you can see that the first section is 3 segments wide. Then there is a step and underneath this step is a small circle. This is the decimal point. The next section is 1 segment wide and then there is another step. The following section is 4 segments wide, and so on until the final number encoded is 3.141592654. Michael Reed, the astrophysicist who first decoded the image, is quoted on as saying:

"The fact that the Pi decimal point is included and there is rounding up to 10 decimal places is to me a little mind boggling!"

The location of the new Pi crop circle is 51.488258 degrees north, 1.771964 west, but unfortunately it has not yet appeared on Google maps.

This latest crop circle has appeared on the eve of the new X-files movie I want to believe and has created quite a storm amongst crop circle enthusiasts. Lucy Pringle, a crop circle researcher, was quoted in The Scotsman as finding it hard to believe such an intricate crop circle could have been created by humans, and whilst there was rain the night before it appeared, there was no mud inside the formation.

"You can do it on a computer, but you try putting that in a field in the middle of the night and achieving that degree of mathematical accuracy."

Pringle's theory is that crop circles are created by a spiralling electromagnetic force that hits the ground for a nanosecond.

Local councillor Stewart Dobson said: "It's hard to believe somebody managed to work (the design) out so it shows pi so accurately. It's either a very educated person who has done it or a very educated alien." I think that an alien capable of making it millions of light years across the Universe to visit us is more than likely to have some understanding of pi...

The mysterious Mr Science rock carving of BrazilIt is not the first time mathematics has appeared in a crop circle. Indeed, whether it's the nerdy nature of crop circle fraudsters, or because aliens choose maths as a method of communication because of its fundamental role in the Universe, mathematical patterns are fairly common. One of the best-known mathematical crop circles appeared in the form of the Julia set 12 years ago, again in Wiltshire, near Stone Henge.

For the latest buzz on this crop circle, and to have a peek at all the theories regarding it, see crop circle connector. And whatever caused these mathematical imprints on the face of the Earth, always remember, the truth is out there.

It reminds me of the mysterious alien Mr Science rock carving of Brazil. Some things are just not meant to be understood.