Last year I stumbled upon a book called “The Back of The Napkin” by Dan Roam which is all about “visual thinking” and how to use simple drawing techniques to solve problems. I was sitting in a doctor’s waiting room when I picked up a supplement of The Guardian newspaper and saw an article about the book. It looked like the kind of thing that interests me and so I rapidly followed this up by purchasing and then reading the book. I enjoyed it and dabbled with the ideas a bit but that was about it (although I did completely alter the way that I delivered my first year physics lectures as a result). Anyway, the author, Dan Roam, also has a website/blog and I always keep an eye out for interesting bits and pieces that appear on this so I was really pleased when I spotted an entry which links to a 60 minute presentation given by Dan Roam about his visual thinking techniques (here is a link that goes straight to the full presentation – to get this to work I have found that I need to click it once and wait for it to finish downloading and then click it a second time to actually watch presentation). I’ve just watched the whole presentation and it is a really nice introduction to the material covered in the book and has re-inspired me to look at these ideas some more.
Category: Random stuff
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Humans as ultra-mobile worms
Any alert readers of this site (ha, as if there are any readers…) might have noticed that I am gradually working my way thorugh some recent back issues of New Scientist highlighting a few interesting articles along the way. Something that intrigued me from New Scientist Issue 2697 (28 February 2009) was the response to a letter from a parent asking a question on behalf of their daughter (age not given). The daughter wanted to know why humans have evolved to have two systems to excrete waste products (“poo” and “wee”). I’ve never thought about this before, but the responses indicated that in fact we only have one real excretion system, “wee”, as this takes waste products from inside our bodies and ejects them to the outside. It turns out (and this is the good part) that really our bodies can be thought of as having an elongated annular shape, by which I mean that we are a chunk of connected organic matter that surrounds a long tube. We feed by drawing material in through our mouth, squashing it about a bit, squirting acid on it, sucking the good bits into our interior and leaving what is left to drop out of the end of the tube. This is certainly a very different view of things, but clearly it is not wrong. Now I keep thinking of humans as being quite like some ultra-mobile and (presumably) ultra-intelligent worms, roaming through space enveloping food, and leaving a trail of waste behind us… What a great question.
Sunshine on a rainy day
It is a rainy day today here in Plymouth so it’s a good time for me to draw attention to a fascinating and very beautiful image of what visible light from the Sun looks like when it is split into its constituent colours in New Scientist Issue 2697 (28 February 2009). It would be a breach of copyright for me to include the image in this post but here is a direct link though to the image on its own.
VAT’s a mystery
If I buy a cappuccino from the canteen at work it costs me £1.09. If a student buys a cappuccino from the same canteen is costs them 95p. I believe that the difference (14p) arises because students do not have to pay Value-Added-Tax (VAT) on their food and drink purchases whereas staff do. I can understand this but what I would like to know is does it make a difference i) who drinks the cappuccino? or ii) who’s money is used to buy the cappuccino? or iii) who hands over the money that is used to buy the cappuccino? What would happen in each of the following situations:
- I buy a cappuccino for a student to drink
- A student buys a cappuccino for me to drink
- I use a student’s money to buy a student a cappuccino to drink
- I give my money to a student to buy a cappuccino for me to drink
- I give my money to a student to buy a cappuccino for them to drink
- A student gives me the money for me to buy myself a cappuccino to drink
It seems to me that in cases 1, 3 and 4 the cost of the cappuccino is £1.09 and in cases 2, 5 a 6 the cost is 95p but in cases 2, 4 and 6 I get to do the drinking and in cases 1, 3 and 5 the student does the drinking. Case 4 is the best one for me, so if any of my students are reading this and want to come to some kind of arrangement, feel free to get in touch (there’s the seed of a money-making idea in here somewhere).
Ice circles
In the first year tutorial sessions that I run on our Ocean Exploration and Ocean Science courses we give all of our students an opportunity to give a short informal presentation to their group on a topical piece of marine science news (though sometimes the topics, being selected by the students, have relatively little to do with marine science). The idea is that these presentations are a prelude to an assessed presentation that the students give later in the term and a chance to get a bit of practice and confidence-building. Most of these presentations cover topics that I am familiar with but occasionally they throw up something completely new to me… A couple of weeks ago we ran this year’s sessions and one of the students spoke about “ice circles”. These are, what appear to be, perfect circles of ice that form in rivers and rotate slowly as the river flows around and underneath them. One such ice circle, 10 feet wide and potentially the first to be observed in a British river, had recently formed in the River Otter in Devon and the news story had been picked up by this student’s home local newspaper (and reported subsequently in various places including here in The Times newspaper). Apparently ice circles are much more common in Scandinavia and there is some debate about how they form with one suggestion being that they are the result of alien activities… whatever the truth (and personally I don’t go for the alien stories) it’s well worth having a bit of a google for “ice circles” to look at some of the spectacular images that are out there on the web.
Eight is not the magic number
I spend quite a lot of my time in meetings of various committees, sometimes acting as Chair. So, it is perhaps not surprising that I was interested to read a recent New Scientist article (“The curse of the committee”, Issue 2690, 10 January 2009) describing some recent work by a couple of Austrian physicists which set out to create a mathematical model of the interactions that occur in committees and organisations of various sizes. This work revisits ground covered in the 1950s by C Northcote Parkinson (who is one of those “famous” people belonging to my “I know the name but I don’t know why” category). Parkinson is best known for the so-called “Parkinson’s Law” which basically states that work expands to fill the time available for its completion (a principle that certainly seems to have a lot of truth in it). Anyway, the new research explored how the size of a committee or administrative structure influences its effectiveness.
Based on knowledge of organisations throughout history, Parkinson argued that there was an upper limit on membership size beyond which an organisation becomes ineffective and will split into smaller units. The new research supports Parkinson’s hunch but more intriguingly, it was found that when the number of decision-makers involved in a group decision-making activity is eight there is a very high probability of deadlock occuring with the group splitting into two equal but opposing factions. So, the number eight is simply a bad number for committee membership etc. Thinking about this a little, it seems to me that this is an obvious result – look at the symbol for number eight: 8. It’s made up of two small loops (two groups) that touch each other but don’t overlap; two opposing factions that are unable to reach a consensus, like this:

Sparrow rescue
Earlier today I was in our garden clearing up some fallen twigs and leaves when I spotted a distressed sparrow hanging upside down in one of our trees. On closer inspection it became apparent that one of its “toes” (I’m not sure that birds have toes but I think you’ll know what I mean) had become tightly fixed onto a very small but strong branch by some fine white tape which the sparrow must have been collecting as nesting material. I guess that after the sparrow was initially trapped it managed to twist the tape tighter and tighter around its “toe” as it struggled to get free. I called my wife over and while she supported the bird with a dust-pan I tried to free the bird by removing the tape but our initial efforts were unsuccessful, partly because the tape was so tightly wound but also because one of our next door neighbour’s cats had also spotted the sparrow and was determined to make it a bite of lunch… In the end we had to call out our eldest daughter to remove the cat and once this was done we were able to concentrate fully on the rescue. With one neat snip of my pen-knife scissors the tape was cut and the sparrow immediately flew away, taking refuge in a nearby tree. At first we thought it might have suffered permanent damage because it sat there fluttering about whilst all its friends twittered wildly, but after a few more moments it flew off again and from the last we saw of it, it seemed fine. It is amazing how much saving a life like this, albeit the life of just a little bird, leaves you feeling like you have done something really worthwhile.
The Poles are not healthy
The staff canteen at work has a number of TV screens on the walls that are invariably tuned to BBC News 24 or Sky News. Fortunately the volume is turned down to zero but the screens display the instant subtitles that can accompany the news feeds. I always find it interesting to read these subtitles when I am waiting for colleagues to join me at lunchtime etc. It is amusing to observe how badly the spoken words are translated into subtitles and there are often great mis-translations that entirely alter the meaning. One such gem occurred today in a political report. The reporter must have been talking about the current level of support for the Government in the latest opinion polls but the translation came out as “The Poles are not healthy”. So there you have it, the hard-of-hearing across the country will now be thinking that the Polish people are suffering from ill-health. It’ll be down to eating too many meat dumplings, too much fermented cabbage and that dreaded extra slice of poppy-seed cake I’ll wager (information on Polish cuisine courtesy of Wikipedia).
Extreme ironing
I used to teach a student who listed Extreme Ironing as one of his leisure pursuits. For the uninitiated, Extreme Ironing involves taking an ironing board and an iron to a remote or in some way difficult location, setting it up and then doing so ironing. If you don’t believe me, you can check this out for yourself with this BBC News report from 2002. Being a diver, his particular brand of the sport involved ironing underwater…
Recently, news of a different sort of marine ironing has come to the fore, namely the idea of adding iron (the chemical element) to ocean waters in order to promote growth of phytoplankton (microscopic plant life). Iron is a nutrient that is required for phytoplankton growth but it is lacking in many parts of the oceans. It is argued that the enhanced phytoplankton growth caused by the addition of iron leads to increased absorption of carbon dioxide from the ocean waters which then absorb more carbon dioxide from the atmosphere. When the plankton subsequently die the solid parts sink to the seafloor taking the absorbed carbon with them and forming sediments in which the carbon remains locked for thousands of years. Thus the plankton bloom caused by the increased iron level serves to remove carbon dioxide from the atmosphere and so reduces its impact there as a Greenhouse Gas and its contribution to global warming. That’s the theory anyway and there have a been a couple of small scale experiments to try to see this process in action and establish its potential for a means of reducing atmospheric carbon dioxide concentrations. Not surprisingly, this is a controversial topic as it is not clear how efficiently it would work and what other impacts adding iron might have to marine ecosystems. Now there are plans for a new (larger) experiment on iron fertilisation in the Southern Ocean and there was a nice piece about this, and about measurements of the effects of naturally occuring iron fertilisation caused by volcanic islands, on the BBC Radio 4 programme “The Material World” last week. Further details and more relevant web-links can also be found at this related BBC News report.
The most fun you can have with 31 small pieces of paper?
Every week this term I am taking a couple of one hour sessions with first year students that are designed to improve their understanding of basic statistical concepts – you might know this already because you might be one of those students (or you might be saying to yourself “so that’s what it’s all about”). This week’s session (Number 5 in a series of 9) is all about exploring the difference between population statistics (i.e. statistics obtained when the whole population has been measured – such as the mean height of all students at the university) and sample statistics (statistics obtained when it is only possible or practical to measure a subset of the whole population – such as the mean height of 100 randomly chosen students at the university). Usually it is only possible to measure sample statistics but what we really want to know are the corresponding population statistics.
So, the session involved taking an entire population of measurements (the 31 maximum daily August temperatures in Plymouth in 2003 as it happens) and calculating the mean and standard deviation for this population. Then small samples of varying size (2, 4, 8 and 16 values) were selected randomly from the population and the sample mean and standard deviation for the sample were calculated in each case. When you do this lots of times you find that the statistics obtained with the small sample sizes vary a lot and can be a long way off the population statistics but when the sample sizes are larger there is less variation and the values are close to the population values (which is a fairly obvious result but still a nice one to demonstrate). Anyway, the fun part revolved around how the students obtained their random samples from the population. To do this I gave small groups of students a strip of printed numbers (1 through to 31) which they ripped up into 31 small pieces of paper (each with one number on) then folded (to obscure the numbers) and then randomly picked however many numbers they needed. It is such a simple process but at the end of a busy day (for them) it was a joy to watch them all merrily ripping up their paper strips, mixing up the numbers, drawing them out and then doing the calculations. They were smiling and laughing and joking when they messed things up and I was instantly struck by the thought that this must undoubtedly be the most fun you can have with 31 small pieces of paper. Unless that is, you know otherwise…