Water, the cause of surfing.

English: Environmental Science student samplin...
English: Environmental Science student sampling water from a stream. Picture courtesy of Environmental Science program at Iowa State University. (www.ensci.iastate.edu) (Photo credit: Wikipedia)

I came across one of those pages on the Internet which state something like “At least a few molecules of the water in your body probably passed through the kidneys of Julius Caesar“. They generally use statistics to show that what they are saying is true.

Only those who believe in homeopathy should be disturbed by this. To anyone else, a molecule of water is a molecule of water, and the fact that it had once been contained in a stream of urine is irrelevant. In any case it is too late. 60% of our body is made up of water, so water from Caesar’s urine is already in us.

Julius Caesar, Summer garden, Saint-Petersburg
Julius Caesar, Summer garden, Saint-Petersburg (Photo credit: Wikipedia)

Water is a fascinating chemical. It carries stuff around as it is the basis for blood and lymph and all the other fluids of our bodies. It carries nutrients up the stems of plants. It wears away mountains and builds rocks, it cools lava to form other rocks. It brings nutrients to our crops and washes them away. It even sinks ships.

“You are water
I’m water
we’re all water in different containers
that’s why it’s so easy to meet
someday we’ll evaporate together.”
― Yoko Ono

It’s difficult to think of any occurrence in our familiar world which is not mediated or affected by water in some way. Shortage of water to a society is a disaster, as food cannot be produced, leading to famine and deaths.

Much of the western U.S. is in "extreme d...
Much of the western U.S. is in “extreme drought” (Photo credit: Wikipedia)

Water is thought by most people to be liquid at usual temperatures, though there are some places where it is to be found in solid form. Actually there is a great deal of it around in the gaseous phase, or vapour. We measure this airborne water in terms of the humidity or wetness of the air.

Water is extraordinarily pervasive and can be found in all the nooks and crannies in the materials that we have around us. It acts as a lubricate, and if the water is driven off, by heating or chemical means things become stiff and fragile. Even so, water cannot be completely removed from things – even a diamond probably has a few entrapped water molecules.

Water molecules attaching to each other by hyd...
Water molecules attaching to each other by hydrogen bonds (Photo credit: Wikipedia)

Water plays a role in rotting things down. A corpse kept in a very dry environment desiccates and turns leathery and fragile. I guess that this is because the organisms that rot a body away cannot function in a water free environment.

A body of liquid water fills things from the bottom up. Gravity pulls the water down to the lowest parts of a container and water continues to layer the container. The surface appears to be flat, but that is an illusion. At a small scale, if a tiny bit of the water happens to be higher than the rest of the water, gravity will pull it down, while the other water molecules resist by being in the way.

English: Dilmah - photo by me on today.
English: Dilmah – photo by me on today. (Photo credit: Wikipedia)

Eventually as the water stills, the differences in level even out, and the water surface becomes as level as it can. However, at the molecular level, molecules of water, which are moving relatively fast on these scales, can pop out of the liquid and float away. Other molecules can also pop in to the liquid, so that on average the water is level.

Why doesn’t the surface appear blurry and ill defined then? Well we can’t see at the molecular scale, and also the water molecules form weak electrical bonds with each other. A water droplet is like a large crowd of people all milling about, holding hands much of the time. Those on the outside are not as tightly bound as those further in.


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Imagine now that the crowd is surrounded by a storm of people who are moving faster, and are more spread out so they rarely join hands. One of these gaseous people will now and then bump into the crowd. They may knock loose one of the crowd who will shoot off and become one of the gaseous people, while gaseous person who hit him may now be travelling more slowly and link up with the crowd.

Even in the macro world a water surface is rarely really flat. The dynamic nature of the flatness is apparent when a container is jolted slightly and tiny waves form on the surface as compression waves disturb it. Wind and rain also cause visible disturbances in a lake or pond.

Surface waves
Surface waves (Photo credit: Wikipedia)

Flowing water often forms a smooth, if not level surface. A submerged rock in a river or a weir or fall in a river can form persistent ripples of flumes as the water flows over them. Kayakers know to aim their craft at a flume to safely descend a rapid or waterfall, although downstream of flumes the river often forms “haystacks” where turbulent water is forced into humps which can prove difficult to navigate.

A little stream may be described as turbulent as it makes its way over and around boulders and small drops, but interestingly it is not random. It is not chaotic. A close look will reveal that the bow waves of stones in the flow may flutter and throw off little whirling vortexes, but the bow wave and the pattern of vortexes persists. The little waterfall over a small stone ledge persists, even though the shape of the waterfall may ripple a little.

Ripple effect on water.
Ripple effect on water. (Photo credit: Wikipedia)

In large bodies of water, such as lakes and seas, winds form waves which can travel many thousands of kilometres across oceans and seas. Water waves don’t represent the movement of water over those distances – the only thing that moves is the energy in the wave. Water molecules in a wave move mainly up and down and only a little forwards and backwards.

Circular water current in a wave
Circular water current in a wave (Photo credit: Wikipedia)

However when a wave travels over a beach or shoal, the movement in the vertical direction is curtailed, and the energy is transformed into a forward motion – the wave breaks. Water is transported forward, with the water higher up moving faster than the water at the sea bed which may be water draining off the beach from the previous wave and the wave steepens until it collapses. Hence surfing!


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Early television and that mess of metal on the roof

English: British Murphy black and white 405 li...
English: British Murphy black and white 405 line Television receiver 1951. (Photo credit: Wikipedia)

In the beginning the consumer television set was a large box with a small blurry screen. To successfully receive one of the few channels being broadcast one needed an aerial to pick up the broadcasts. They came in two sorts. One was a huge “H” or “X” shape that was located on the roof and aligned with the signal from the broadcaster. The other was a small device consisting of a base made of plastic and two metal prongs, known as “rabbit’s ears“.

Of the two types you will only see the rabbit’s ears aerial still being used today. Since television has moved from the VHF (Very High Frequency) band to the UHF (Ultra High Frequency) band, television aerials have shrunk in size and the technology has now improved so that television aerials have become the compact roof top Yagi style aerials that are common today.

Nederlands: Schets Yagi antenne
Nederlands: Schets Yagi antenne (Photo credit: Wikipedia)

Although it is obvious from the shape of the Yagi aerials that they receive a directed signal, I suspect that not many people know why they are the shape that they are. There is only one element that picks up the signal and that is one of the cross bars on the main shaft of the aerial. All others elements (including the mesh element at the back if there is one) serve to concentrate and direct the incoming signal towards the main element or dipole.

This means that the aerial can pick out weaker signals from general noise but it does mean that the aerial must be aligned fairly accurately with the transmitters signal.

English: Communal aerial This seems to be a co...
English: Communal aerial This seems to be a communal TV aerial for the farms hidden between Baugh Fell and the Howgills. (Photo credit: Wikipedia)

There is a new type of aerial that has become common in recent years and that is the dish aerial. Dish aerials are generally used to pick up signals from stationary satellites and need to detect weak signals broadcast from space. The actual dipole is in the small plastic box in front of the dish. The dish is a passive reflector and just concentrates the small signal onto the dipole in the box, much like the Yagi aerial does for UHF frequencies. Satellite signals are of even higher frequency than the UHF ones.


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In the early days of broadcasting and with the use of VHF frequencies, ghosting was a problem. Because early aerials (and “the rabbit’s ear” type of aerials) were not particularly directional they could receive signals which had bounced off various obstacles on their way from the transmitter to the receiver. The reflection from obstacles such as hills and large buildings meant that the receiver would collect signals which had travelled by different routes and hence had taken slightly different times to reach it.

The result of this was that the images on the screen either appeared to have shadows or duplicates. This phenomenon was called “ghosting” and in a bad case it might appear that in a broadcast soccer match that the match was being contested by two teams of twenty two players using two balls.


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This phenomenon is not often seen these days as UHF signals and satellite signals are much more directional and hence do not receive signals bounced from obstacles in their line of view which has a much narrower angle.

In the early days of television technology the electronic equipment in the receivers was in its infancy. The circuits leaked signals between their parts, and components were not as stable as they are today. Valves and other components had to “warm up” to operating temperature and often the oscillators and other circuits tended to “drift” away from the nominal operating frequencies.


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In real terms this meant that those watching the program would often find that the picture would appear to roll up or down the screen. Someone would have to leap up and twiddle the controls at the back of the television to try to stop the picture rolling. Very often the twiddler would adjust the control to stop the rolling, only to find that his or her very presence had affected the circuits and the screen would start to roll as soon as he or she moved away.

Other effects would cause other issues. Unstable circuits would cause the image to shake like a jelly, or tear completely in one or more places. It was a true art form to twiddle the available knobs (of which there were many) to produce a decent and more or less stable picture.


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Screens were small. Early sets had dimensions of perhaps 9 inches (23 cms). Today screens of 50 inches or more are common. Each screen had (in the UK at least) 405 lines all of which were scanned in one or more cycles. The early television tubes were not very accurate and each line could be clearly seen, and so sometimes could the “flyback” as the circuitry returned the beam to the top of the screen for the next scan.

The end effect was a small picture blurred by circuitry instabilities, often with artifacts like the “flyback” lines polluting the picture, and plagued by instabilities, but which showed pictures of news around the world, or educational programs or discussion panels, plays or game shows. And they even broadcast cartoons for the kids. Everyone wanted one, of course!


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Obviously things improved very quickly. Television electronics became much better, and the pictures much more stable especially when transistors were introduced. The screen increased in size, and colour television was introduced. Some would argue that the quality of the television content has dropped dramatically, but that doesn’t change the fact that most people have one or more televisions in their house and it has become the central focus of many lounges and living rooms. Many people have them in bedrooms, bathrooms and kitchens these days.

It is ironic that broadcast television may well have peaked. More and more people use their television sets to show content that has not been broadcast, but which has been obtained over the Internet. It may be that this network distributed content may totally displace the broadcast television service and that people will no longer be tied to a broadcast schedule, picking up content that they want to watch from a myriad of Internet sources.

English: How to connect telephone, radio, tele...
English: How to connect telephone, radio, television, internet via glass fibre Nederlands: Aansluiten van telefoon, radio, televisie, internet via glasvezel (Photo credit: Wikipedia)