Never Mind the Bullocks, Here's the Science (10 page)

Human beings are basically hairless apes with big brains.

Hair Tangles—Experiment

Theory is one thing, but experiment is another.

His experiment involved two hairdressers checking for tangles in the hair of their clients, for three weeks. They checked 212 people (123 with straight hair, and 89 with curly hair) in the late afternoon between 4 and 7 pm. This time was specifically chosen to allow the maximum time and opportunity for the hair to tangle after a hard day of waving about in the breeze and rubbing against the trees.

In science, you need definitions. Therefore, a ‘tangle’ was defined as a ‘cluster or grouping of hairs that resist combing’. This excluded natural clusters of hair, such as a curl or a ringlet. To find any tangles, the hairdressers used a comb with a 3 mm separation of the teeth.

The experimental results were astonishing—on average, 5.3 tangles were found in each head of straight hair, but only 2.9 for curly hair.

At this stage, we still don’t fully understand what is going on.

Why More Tangles with Straight Hair?

The initial theory implies that the shafts of straight hair cross each other less often than do the shafts of curly hair. Now this is reasonable, because you would think that the straight hairs would tend to stay parallel to each other, and not cross each other.

But the physicist’s theory also told him that when the straight shafts do cross, they do so at a greater angle than for curly hair. Perhaps this is the clue—the critical factor. Human hair does not have a perfectly smooth surface. A microscope shows that the surface is coated with fish-like overlapping ‘scales’ with shallow notches.

Perhaps these scales ‘lock’ into each other only when the hair shafts cross each other at a large angle?

Perhaps the individual strands in curly hair tend to move as a single unit, while the strands in straight hair tend to move individually?

The ‘worst’ hair for tangling is dry, fine, chemically treated hair. With this type of hair, perhaps the scales stick to each other very easily? Unfortunately, this early model does not yet account for this fine detail.

Why is Pubic Hair Curly?

This question came up on the Triple J Science Talkback show. I was perfectly honest, and said that I did not know, but that I would go looking for an answer.

I came up with a whole bunch of potential reasons. Obviously, not all of them would carry the same weight, and some of them could even be wrong. But, for better or for worse, here are some of them:

1. Maybe because pubic hair is located in a warmish moist environment, and is scrunched up all the time.
   
2. Maybe it’s caused by the sulphur in the proteins that make up the keratin in hair. Pubic hair possibly has more sulphur, and this sulphur can carry a charge, which can give the proteins in hair a ‘twist’. Perhaps this ‘twist’ gets carried up from the micro scale to the macro scale.
   
3. Maybe it’s caused by the shape of the hair shaft. Apparently, in cross section, the shape of scalp hair is a circle – so it will resist a bending force equally well in all directions. And again, apparently, the cross-sectional shape of pubic hair is like an oval. In the longer direction, this cross section is very strong and quite resistant to bending, but in the shorter direction it is quite weak and susceptible to bending. Anyhow, for what it’s worth, this is another possible (but not necessarily true) reason.
   
4. The sex hormones act on the hair follicles in the genitals to make them generate curly hair – perhaps via oval exit holes for the hair.
   
5. Perhaps curly hairs trap pheromones (hormones that leave the body to travel to another body).
   
6. Perhaps pubic hair is curly to stop it poking you in the eye…
   
7. …and other silly reasons.
   

Anyhow, the next week I came back on air and ran through these ideas hoping that the truth was somewhere in there…

But then a sex worker from Kings Cross phoned in to Triple J and said that she had noticed (in her line of work) that Asians tended to have straight pubic hair. And the next phone call was from a sports coach who was shepherding a group of Japanese sportsmen around Australia. He had noticed in the showers that they had straight pubic hair. And he said that his female counterpart had noticed the same phenomenon in the Japanese sportswomen travelling with them.

So my line of thought was limited by my Western point of view. But, seeing as how pubic hair is becoming a thing of the past with all the Brazilian waxes going on down there – as opposed to out there – this research may never get the public attention it deserves.

We still don’t know where this research will take us. But perhaps it will lead to better Velcro-type materials, because Velcro involves hairy fibres crossing each other and hopefully getting entangled. Or perhaps the large hair product companies will swing the resources of their massive laboratories to finally solving the vexing problem of tangling hair. After all, the problem of tangled hair is a curly one…Or perhaps they aren’t too fussed about splitting hairs!

References

Kunzig, Robert, ‘The biology of…hair: zeroing in on the molecular switches that regulate hair growth’,
Discover
, February 2002.

Masson, Jean-Baptiste, ‘Why does curly hair get less tangled than straight hair’,
American Journal of Physics
, August 2007, Volume 75, Issue 8, pp 701-706.

Nicholson, Christie, ‘Straight hair is knottier than curly hair’,
Scientific American
, 13 March 2008.

Flat Earth
(The Truth is on the Horizon)

There are many false perceptions about what happened in bygone eras. One of the most common ones is that before Columbus, everybody believed that the world was flat. This is not so! The inhabitants of Medieval Europe (back in the 15th century) did not believe that the Earth was flat and that Columbus would simply sail off its edge.

In fact, people have known the Earth to be a ball (or a sphere) for a long time.

The biographer Samuel Eliot Morison wrote in his Pulitzer Prize-winning biography of Christopher Columbus: ‘…for of all the vulgar errors associated with Columbus, the most persistent and the most absurd is that he had to convince people “the world was round”. Every educated man in his day believed the world to be a sphere, every European university so taught geography, and seamen…knew perfectly well that the surface of the globe was curved.’

‘The Last Iconoclast Dies’

This was the headline in
The Fortean Times
when Charles Kenneth Johnson, President of the International Flat Earth Society, died in Lancaster, California, on 19 March 2001.

Samuel Shenton and his wife, Lillian, from Dover in the UK, had founded the International Flat Earth Society in 1956. Charles Johnson became the leader of the society when Shenton died in 1971.

Johnson had embraced the Flat Earth belief when he was just eight years old. ‘When I was at school, the first maps I saw were flat. Then Roosevelt flooded all the classrooms with globes. Well, I didn’t believe it.’

He maintained that our world was a circle of unknown size, with the North Pole in the middle, the South Pole on the circumference, and the whole thing surrounded by a wall of ice approximately 50 m high (the Antarctic ice). The Moon and the Sun, he claimed, were the same size – about 50 km across – and they circled above the disc of the Earth at a height of about 4,800 km. They didn’t touch the sky, which itself was a dome reaching to a height of about 6,400 km. And sunrise and sunset – easy, just optical illusions.

History of Round Earth

About 2,500 years ago, Pythagoras (c. 582-c. 507 BC) postulated that the Earth was spherical, not just a flat circular disc. He did this for aesthetic reasons, because a sphere was supposedly perfect.

Aristotle (384-322 BC) agreed. But he had some experimental evidence.

First, there are the lunar eclipses, where the shadow of the Earth falls on the Moon. These happen at many different times—when the Moon is close to the horizon, or when it is high in the
sky. So, if the Earth were a flat disc, every now and then there would be a lunar eclipse in which the light of the Sun would hit the supposed disc of the Earth at an angle, not square on. This would produce an ellipse on the surface of the Moon. But, instead, every lunar eclipse has the Earth throwing a circular shadow onto the Moon. Aristotle wrote: ‘The sphericity of the earth is proved by the evidence of…lunar eclipses. For whereas in the monthly phases of the moon, the segments are of all sorts—straight, gibbous (convex), crescent—in eclipses, the dividing line is always rounded. Consequently, if the eclipse is due to the interposition of the Earth, the rounded lines result from its spherical shape.’ The conclusion is obvious—the Earth has to be spherical.

Second, said Aristotle, sailors knew that when seeing a distant ship, they would first glimpse the top of the mast before sighting the rest of the ship. Once again, this shows that the Earth has to be round.

And, third, some southern constellations rise only a little above the horizon in the Northern Hemisphere. But, said Aristotle, when travellers went further south, they saw these constellations rise higher in the sky. This could not happen with a flat Earth—but could with a spherical Earth.

About a century later, Eratosthenes of Cyrene (c. 276-c. 194 BC), the Third Librarian of Alexandria, did some very simple geometry based on the length of shadows. He estimated the circumference of the spherical Earth—and got very close to the correct figure!

And well into the next millennium, around 830 AD, the Muslim astronomer al-Farghani, working with other astronomers of Calif al-Ma’mun, undertook a series of measurements. They measured the Earth’s circumference as being 40,253 km—within 0.5% of the current figure of 40,075 km.

Measure Size of Earth with Sticks

Eratosthenes was a Greek who lived in Alexandria in the 3rd century BC. Using just a stick and some maths, he measured the circumference of the Earth.

He had been told by travellers of something wonderful in the Egyptian town of Syene (situated near the giant dam on the Nile, today it is known as Aswan). On just one day of the year, the Summer Solstice, the light of the Sun would reflect off the water in the bottom of a well, for a few moments around midday. That meant that on the Summer Solstice, the Sun was vertically overhead (and that Syene was on the Tropic of Cancer). So on the same day, 21 June, Eratosthenes set up an experiment in his home town of Alexandria. He set up a stick to be perfectly vertical and, around midday, measured the smallest shadow that it threw. The shadow was about 7.2° away from the stick. Now, 7.2° is about one-fiftieth of the 360° that make up a circle.

So that meant that the distance between Syene and Alexandria was one-fiftieth of the circle that makes up the Earth (roughly 800 km).

All Eratosthenes had to do was find the north-south straight line distance between Syene and Alexandria. This came to about 5,000 stadia (one stadia was the length of a foot race in a stadium).

If 5,000 stadia represented one-fiftieth of the circumference of the Earth, then the full circumference was 250,000 stadia.

But a few assumptions were made.

First, Syene was not exactly on the Tropic of Cancer, but slightly north of it. So the Sun was not exactly vertical on the day of the Summer Solstice.

Second, Syene was not exactly south of Alexandria, but a little to the side—so the measured north-south distance between them was a little inaccurate.

Third, the Sun is not a point infinitely far away, so its rays are not exactly parallel. Indeed, over the distance between the Earth and the Moon, they diverge by one-sixth of a degree.

Fourth, it is really difficult to maintain accuracy when you have to pace out a distance of 800 km.

Fifth, how big was a stadia in those days? How many ruined stadiums do you have to average? The Greek historian Herodotus (c. 484 BC-c. 425 BC) reckoned that one stadia was 600 feet. But how big is a foot? Depending on the purpose of the measurement, and which culture measured it, a stadia could range between 157 m and 209 m. So the circumference of the Earth would range from about 40,000 km to about 46,000 km.

Anyhow, depending on the exact measurements used and other factors, Eratosthenes got to within 0.5-17% of the true value—which is pretty good using just a stick as the measure!

Eratosthenes—Always Second Best

Eratosthenes spread himself over many fields. Besides being an astronomer, a geographer and a mathematician, he was also a poet and an athlete. He worked out the circumference of the Earth, and the tilt of its spin axis. He also devised a system of latitude and longitude, and a calendar that included leap years.

His colleagues called him ‘beta’ (the second letter of the Greek alphabet), because they reckoned he was the second best in almost any field.

Myth of Flat Earth

So, for the past 2,500 years, in Europe and in the Middle East, the Flat Earthers were in a very small minority.

At least, this is what the historian Jeffrey Burton Russell, of the University of California at Santa Barbara, believes. His book
Inventing the Flat Earth: Columbus and Modern Historians
claims that since the 3rd century BC, practically all educated people in the Western world believed in a spherical Earth.

Looking into the historical record as an historian, he found tens of thousands of Christian theologians, poets, artists and scientists who believed that the Earth was a sphere. On the other hand, he could find only five Christian authorities who believed in a Flat Earth. Dr Russell wrote: ‘In the first fifteen centuries of the Christian era, five writers seem to have denied the globe, and a few others were ambiguous or uninterested in the question. But nearly unanimous scholarly opinion pronounced the Earth spherical, and by the Fifteenth Century all doubt had disappeared.’