The Mechanics of Electricity

Anything that moves is subject to the natural laws of mechanics.

Note; The “Laws of Mechanics” have been in existence since before there was any life in the universe, and are therefore not related to university degrees, Newton, mathematics etcetera. 

Electricity is electrons in motion, therefore its energy is in the momentum of the electrons. Can this be true?

Consider ‘static’ electricity. Static is a quantity of electrons constrained to stay in one location.  Static normally only occurs on insulators, which do not provide an escape path. Electrons do not like to be close to other electrons (Like charges repel each other),  therefore the electrons are in a (compression) stressed condition, each electron pushing against others. The ‘strength’ of the charge depends on the quantity

Note;

If they don’t like each other why don’t they just leave, you may ask? Unfortunately, they need a pathway or a force to escape because they do not have any momentum, they are STATIC. To become electricity they need to be moving. To become heat they need to be moving. To become light they need to be moving.

How do we get them to move? If we move an object that has less ‘static’ electrons slowly towards our original static charge, eventually they will jump across. Whilst they are jumping across they are electricity.

Note; Deserts are a major source of static. The sand is a fairly good insulator and the constant movement of the sand creates a lot of static due to the breakdown of the sand particles releasing electrons.

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If light is electrons in motion, why does light not travel down a copper wire?

Light is electrons travelling at very high speed. Copper is highly opaque to light and therefore its energy is reduced into the heat range. Shining a light into a copper wire will cause heat radiation(slow speed electrons).

If light travels easily down a glass rod, why does electricity not travel down it?

A lot more to come on this.

Author – Brian Williams.

Physics in the News- Gravity Waves. The Mechanics.

What is a gravity wave? Stand on the sea shore and watch the tide come in. You are watching the result of a gravity wave. This gravity wave, twice daily(roughly) not only moves the seas but also moves the land.

The force of the moon’s gravity creates a moving force field (gravitational wave) that travels around the Earth. This wave is also affected by the gravitational force of the sun, the planets and, to an exceedingly small amount, all other stars and planets in the universe.

All bodies having mass and moving relative to another mass create a gravity wave.

Note that bodies that are in geosynchronous mutual orbits do not create a moving force field and therefore do not create a gravitational wave because the bodies do not move relative to each other.

Yes, I do understand that the current proposed experiments are an attempt by the physics establishment to force gravity into the ‘Wave Theory of Everything’ syndrome. Gravity is a force, not a wave. Light is particle transmission, not a wave.

However, they are attempting to use the same experimental set-up as used in the Michelson-Morley experiment, which is full of errors, both logical and mathematical.

In fact, the results obtained in the Michelson – Morley experiment actually proves that light does not travel at a constant velocity and that light is not a wave.

Also, the experiments are set up on Earth and therefore subject to massive gravitational forces relative to the forces that they are attempting to measure.

Latest World Headlines, gravity waves found, a few computer created graphics, two prints from graphs, but no evidence presented to allow the claims to be checked out.

Author – Brian Williams

See also;

How-Gravity-Works-and-What-Causes-It.

The Full Mathematics of the Michelson-Morley Experiment-Part-1

Liquid Balance On Saturn Satellite Mimas.

Understanding Waves

The Mechanics of True Perspective.

INTRODUCTION.

 Throughout known history man has produced pictorial representations of his environment, from the earliest cave paintings of animals, hunting scenes, weapons, & man, through to the masterpieces of the great painters of the renaissance. Bearing in mind the wide variations in artistic talents of the general population of today, and considering the extremely low population of early man, one is tempted to conclude that early man had a greater artistic capability. Many cave painting have great technical assurance, and considering the severe circumstances in which they were produced, would indicate an enthusiasm beyond that of most artists. Produced on rough rock faces, using charcoal or home-made dyes, applied with sticks, fingers etc., carried out in semi-darkness by the light of guttering torches, and in an atmosphere full of smoke, it is doubtful that many of our great painters could have done better in the same circumstances.

If these same cave painters had sable brushes, stretched canvases, and the wide variety of painting media that we have today, they would be world famous artists. It is sad to consider that their greatest works would have been done outside the caves, in more congenial circumstances, but these would have been destroyed by weather and erosion.

It is clear that these cave painters understood the importance of perspective, demonstrated in many of the their paintings. Even the artists of ancient Egypt, often unjustly accused of not being able to ‘draw properly’ (See later note.), understood the basic requirements of perspective.

The technical aspects of perspective were intensively studied during the renaissance, and in fact our present systems of perspective show no improvement on these early studies.

I first became interested in perspective whilst a student at Bolton Municipal College of Art, where, having a keen interest in mechanics as well as art, I was intrigued by the apparent incompatibility between the art of perspective and the mechanics of perspective as given in all the text books on the subject.

One of the points that emerged from my later research was the practical incompatibility of the art of perspective, with the mechanics of perspective. This will become apparent as we continue.

A further point relates to what in many cases are referred to as ‘ optical illusions’, or faults in our eye or brain. In fact, many of these are accurate assessments of the information (in the form of light) that is arriving at the eye.

Note: – The stylised ‘side only’ drawings on most Egyptian artefacts were certainly not created due to any lack of ability to draw full frontal or angled drawings. The artists’ abilities are clearly demonstrated by the large number of superb statues, masks etc. in existence. There are also full frontal drawings in existence that were patterns for statues. There are various possible reasons for the stylised form of art;

a. Economy. It is easier to draw figures in this way, and the large numbers of figures in most tombs etc. would made this an economic method of drawing.

b. Suitability. Most figures are carrying out some form of activity. It is easier to show these activities in a side view rather than a full frontal or angled view. This style of drawing figures is often used in instruction manuals today.

c. Labour. It is unlikely that the master artist carried out all the paintings, therefore numerous other artists or semi-skilled technicians would have carried out the work. ‘Patterns’ would be used for guidance by these ‘auxiliary’ artists.

d. Style. More realistic drawings methods would lose much of the important aspect of the drawings, i.e. they are primarily a means of recording messages. Every picture has clarity of meaning, even if the picture is not truly realistic.

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True Perspective.

The simple drawing below is of a group of buildings. This is actually what you see, even though you will initially argue against my statement.

 Let us look at Fig.2 which shows four areas to consider.

Let us now look at these areas in isolation.

Looked at in isolation, as happens with the human eye’s small area of high definition, I think you will agree that they do not seem to be particularly distorted.

Normal Methods used in Perspective.

Author – Brian Williams

Much more to come on this subject.

Understanding Heating and Ventilation – Rev 1

Originally posted on October 3rd, 2010. (In the last few weeks it disappeared for some unknown reason)

Understanding mechanics is nothing to do with mathematics, it is the reality of what is actually happening and why it is happening.  Note:- I have been asked “what has heating and ventilating got to do with mechanics?”

Mechanics is about moving things, and relates to anything that moves, whether levers, steam engines, ships, aircraft, spacecraft, arms and legs, water, sewage, blood, air, heat, light, magnetic radiation, radio waves, electricity etcetera.

Heating and ventilating is primarily about moving air, water and heat.

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As one of the jobs that my wife has added to my very long list of things more important that physics, I am now in the process of redoing my loft insulation, a most uncomfortable job.

This has brought to mind an occasion many years ago when one of my duties was to arrange for ‘Air Curtains’ (An industrial version of the air curtains found in many shopping centres and stores.) to be fitted to the industrial doors in a large production area.

I arranged for quotations from 6 manufacturers.  Over the next few days I took manufacturers engineers around the production area to enable them to produce their quotations.  These visits normally took about 2 hours.  However, one manufacturers engineer was there for two days.

The following week  I received the quotations and arranged separate interviews with the manufacturers to discuss their quotations.

The company whose engineer had taken two days I left till last, because their quotation had been the lowest and I was curious.

When I finally asked them how they had arrived at their price, I was given a technical file of about 30 pages.  That included the details of every single source of heat production within the manufacturing area.  This included machinery, pipe-work, workers and normal heating devices.  It even included variations allowing for summer/winter and night/day.  They got the job, but I had difficulty with our directors, who had a practice of throwing the highest and lowest quotes out, and then choosing between the remainder.  They did not understand that being a real expert allowed you to bring your prices down.

What finally convinced them were the running costs and guarantees.

The same problems arise with home heating and ventilation.  Every item in your house affects the temperature and ventilation requirements.  Heating costs are higher in a ‘minimalist’ environment,  (all goods and furniture are like storage heaters.) An empty room can lose all its heat in a few minutes, but an over furnished house will take hours to drop to the same temperature.  I have been looking after an old terraced cottage for a lady in hospital for 12 months.  The cottage is stuffed with furniture and other goods, but over the severe winter in which outside temperatures hardly ever got above zero, the temperature inside the cottage never felt uncomfortably cold.  There is no central heating in the cottage and the only form of heating was a gas fire, and the gas was turned off.

Like our manufacturing area, every item in a house either stores heat or produces heat.  The heat storage includes walls, furniture, goods and even items down to cutlery and children’s toys.  The heat producers include lighting, electrical equipment, bodies (including animals) sunlight and finally your main heating source whether a central-heating system or electric fires, gas fires or solid fuel burning.

Basically your central heating system compensates for reductions in the overall heat input into your house.

If you decide to switch off all your lights, the central heating system will compensate for the heat loss.  (The energy dissipated by lighting is nearly all heat, only a  small amount is radiated as light, and most of this is converted to heat when striking some object.  In the olden days when I was a lad, it was not uncommon for people to put an electric light bulb in a biscuit tin or similar metal container to use as a heater)

If everyone leaves the house, the central heating system will make up for the heat loss.  If you let the cat or dog out, the central heating will make up the heat loss.  If you switch off all your electrical equipment that is in standby mode, the central heating system will make up for the heat loss. However, if the outside temperature is high, switching off ‘heat producing items’ will save you from discomfort and save you money.  During the summer we had about 8 days in which the central heating was off, but the radiators were still very warm due to the heat accumulated in the roof-space, and we had ‘free’ hot water for a week.

Normally, in Britain, you will only save energy by ‘energy saving light bulbs’ or switching off electrical goods that are normally on standby mode’ when the outside temperature is higher than the set temperature of your central heating system, and that doesn’t happen very often.

I have saved a little bit of energy by adding external insulation to our freezer, (its under the stairs in my computer room so it doesn’t worry about looking pretty).  I used under-floor insulation which is only about 2.5mm thick but is a good insulator.  If you put your hand on anything and feel the cold immediately, then it is a serious source of heat loss.  The only problem is that fridges and freezers circulate heat.  Any heat removed from inside the fridge is returned through the radiator at the back.  Obviously, if your fridge or freezer is outside in a garage or shed you should save energy and money.  However, if it is inside the house you will not save much money however ‘energy efficient’ it is.  My computer room is about 5 degrees Fahrenheit cooler than the rest of the house therefore I save some heat.

Generally, it is better to look at more obscure methods of saving heat.  Many people will quite happily insulate the hot water pipes in a house, but ignore the cold water ones.  However, the cold water pipes in your house absorb heat from the general house temperature.  In winter, flushing your toilet loses more heat than boiling a pint of water.  (I will be carrying out some experiments to verify the actual amount lost, and trying a method of insulating the cistern on the inside to reduce heat loss into it, and also reducing the condensation on the outside which can be a problem sometimes)

When you run your cold water tap, the water in the pipe-work has been absorbing heat from your house, which is then generally flushed down the drain.  (This depends on how close to the main water inlet  to your house is to the particular tap you are running, complicated isn’t it?)  Water can absorb a lot of heat, which is why it is used in central heating systems.  The ideal solution for showers is a heat exchanger in which the draining water heats the incoming water feeding the shower.  This can save approximately 40% of the cost of running the shower, but can be difficult to construct in many houses.

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How HOT Is It?

Many people get confused when attempting to estimate whether something is hot or cold.  This, in many cases, is because of the ‘rate of heat flow’ between different materials.  In between the two extremes of freezing and boiling (or burning) there is a ‘comfort zone’ in which no damage is caused to the human body.  At freezing point damage can be caused due to the high water content of the human body.  At boiling point the water in the human body starts to boil.  Both are obviously dangerous situations.

However, if you have both a cushion and a piece of steel at freezing point it will be fairly obvious, if you touch it, that the steel is at freezing point.  You would probably argue, on touching the cushion, that it was a lot warmer than the steel.  This is because the rate of heat transfer (RHT) between you and the cushion is a lot less that that between you and the piece of steel.  There is energy passing from your hand to the cushion or the piece of steel.  The human ‘machine’s’ heat detection system uses this ‘rate of heat transfer’ to assess danger levels.

When the RHT is too high, damage is done to the body.  This applies whether the heat is travelling out of the body or into the body.

There is a similarity between the action of low temperatures and the action of low pressures.

See Understanding Pressure and Vacuum.

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Ventilation

Ventilation is a major source of heat loss, whether by open windows, open doors or just draughts.  Unfortunately we cannot manage without ventilation.

All ventilation is a source of heat loss.  With doors the airlock principle works quite well, but is subject to the fact that the door is open for particular reason, and generally the reason takes your mind off saving heat, and the door is left open longer than necessary.  There is not a lot you can do about human nature.

Windows have a tendency to be opened when a room becomes stuffy.  Unfortunately, it gets left open until someone claims that it is too cold!  Your central heating then has to make up for the lost heat.

Most houses have a heat store that is ignored, and that is the roof space.  This heat can be re-used both for heating, and reducing the heat loss due to ventilation.  Its use for heating is used in quite a few industrial buildings, where the warm air at high levels is ducted down to lower levels with the aid of small fan units.  Note:-  It is advisable to thoroughly clean the attic with a vacuum cleaner before using it as a source of warm air, alternatively bring fresh air into the attic via a galvanised duct (preferably rectangular, it gives a better heat transfer) to isolate the air in the attic from incoming air.

It can also be used to warm-up ventilation air by running a separate duct at high level in the roof space (the fan unit should be at the ‘fresh air’ end of the ducting so that the duct is at positive pressure).  Note that a fine mesh filter should be fitted to the air intake to keep out wasps and other undesirables.  You would not be pleased if a swarm of bees arrived in your living room by way of your heating duct.

All ducting should be of galvanised steel, not stainless steel or plastic.  The zinc on galvanised steel is fatal to many bugs and viruses.  I have a feeling that many of the cases of ‘Legionnaire’s Disease’ may be caused by the use of plastics or stainless steel for the ducting.  These materials are relatively inert, so a warm ducting is an ideal environment for many ‘nasties’.  This problem may also occur in water systems where storage is by plastic or stainless steel tanks.

SEE ALSO “Boil or Carbuncle?”

Tip from my recent attic insulation antics. I had to carry out some extra electrical work and therefore needed to clear some of the insulation. I decided to cover the area of insulation I had to remove, with a thin plastic dust-sheet. Folding the insulation back using two pieces of wood, after doing  the electrical work the insulation folded neatly back without sticking to the rest of the insulation. I followed this by doing the rest of the attic in the same way. It keeps the dust off the insulation and in the case of any small water leaks will help to isolate the damage. Note: do not try to cover the entire attic with one sheet, multiple sheets help to retain some necessary air flow.

More to come on this.

Understanding Mechanics – Waves.

A major subject brought up in physics discussions is wave mechanics. Unfortunately, physicists know very little about waves and almost nothing about mechanics therefore you cannot really expect anything sensible from their discussions.

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Waves are mainly divided into two groups.

Group A  is the transmission of energy. Normally travelling waves

Group B  Is the transmission of mass. Normally standing waves

Both groups are further divided into Generated waves and Created waves.

If you drop a pebble into a pond waves are created that transmit energy. They are created because the pebble does not have any ‘wavelike’ properties and the ‘falling’ motion does not have any ‘wavelike’ properties.

Generated Waves

Electrical/radio waves are generated. The waves in a ripple tank are generated. The large waves sometimes found in holiday swimming pools are generated.

Generated waves follow a ‘pattern’, like the electrical generator that may rotate at 50 revolutions per second will generate electrical waves at a frequency of 50 cycles per second. The pulse mechanism on the ripple tank will generate waves at the same frequency as the mechanism itself.

Created Waves.

Normal waves in the sea are created, and are caused by two different mechanisms.

A. Being caused by the winds operating over the oceans.

B. The tidal flow across the Earth.  (Note; the tidal bulge itself is  a generated wave, it follows the ‘pattern’ of the moon’s movement around the Earth.)

If there was no land-masses the tidal bulge would flow smoothly across the globe. However, due to the land masses. parts of the tidal bulge ( really a single wave travelling around the Earth) are reflected from the land creating waves which are transmitted back into the seas. (This wave creation normally requires a vertical face to reflect from to create serious waves.)

Tsunamis are created, and may be considered in the same way as dropping a pebble in a pond, in that  they may be caused by a landslip (massive pebble). Tsunamis may be caused by a sub-sea  earth-quake or volcano, but the mechanics involved is the same as dropping a pebble in a pond.

However, when a tsunami hits the shoreline the transmission of energy changes to a transmission of mass. All the energy stored in the tsunami is transferred into moving the mass of water onto the land. If the tsunami hits a vertical rock face then a wave is created that is reflected back across the ocean

Ripples on the Beach.

These should be considered as created waves. They are formed due to the water rushing up the beach picking up sand particles. As the amount of sand in the water increases, the extra weight slows the speed of the water and the sand begins to fall out again. This pick up and drop out creates the ripples. The same thing happens as the water retreats down the beach and the ripples are changed again.

Neither the sand nor the water surge up the beach have any wave-like properties

Waves and Ripples in the Desert.

Caused in the same way as ripples on the beach, but by the wind instead of water. The huge dunes seen in deserts are the ‘sand breakers’, the equivalent to the sea breakers beloved by surfers. The wind speeds in the deserts are higher than the water speeds in the sea.

Neither the sand nor the wind has any wave-like properties.

Neither of the above two are really waves, but ‘wave-forms’. True waves must transmit mass or energy.

Obstruction in Smooth Flow.

If you have a smooth flow of water and you poke a stick into the water, then waves/ripples are created in the water just in front of the stick and pass each side of the stick.

It is clear that neither the water nor the stick have any wave-like properties.

In this situation there are three distinct actions occurring.

A. Below the surface of the waveform itself  there is an increased flow of water (mass) along the waveform.

B. The surface water flow passes over this flow. (If you drop a light object such as a petal onto the water surface upstream of the stick, the petal will cross over the waveform without deviating.)

C. As the waveform travels downstream it also moves sideways, (as a boats wake does). This indicates that there is also a transfer of energy sideways. (This is caused by slumping of the waveforms)

(In water waves you also have to allow for differences in speed between the surface water and the various sub-surface levels.)

Sorry about this , but fluid mechanics are extremely complicated, and light follows the laws of fluid mechanics.

Accelerating Waves.

See also ‘Introduction to Physics’. Click on tab at top of page.

Brian Williams – Author

What is an Engineer?

First of all and most important he/she must be interested in how things work. This is called CURIOSITY. Unfortunately, curiosity is also very dangerous and many budding engineers have died because of it. Therefore AWARENESS is also an important ingredient in an engineer’s personality. Awareness usually comes from EXPERIENCE, and is a type of controlled fear. This  fear may be similar to that causing me to be  aware after being belted for pulling my dad’s alarm clock to pieces when I was quite young. This didn’t stop me from pulling alarm clocks apart, but I always used ones that were ‘dead’.

My first experience of electric shock was when I was about  8 years old. Luckily, it was only about 40 volts but was about 60 amps. I was badly shaken and had a few burns but it  was a valuable learning aid that has probably saved my life since.  Note:  Fear may save you from electrocution. I had a friend in the scouts who used to check whether a light socket was live by wetting his finger and sticking it in the socket. NOT A SENSIBLE THING TO DO. It works with some people, the others are dead.  Later in life I found that if  I was stressed  my body increased its electrical resistance, which would reduce the chance of a fatal accident. Fearless or unaware people tend not to be stressed and therefore are more likely to be killed by electric shock. However, don’t chance it. I have carried out ‘live’ connections on 240 volt supplies, but only with suitable safety precautions,  and, I can assure you, a very high stress level.  ( I used to have rubber gum boots,  a 25mm x 2 Metre x 1 Metre rubber mat, and  insulated tools and gloves).

Another valuable ingredient is to learn from other peoples experiences as well as  your own. (Never say “It can’t happen to me. It can.)

Learn to find the interest in any particular job. I have had numerous ‘boring’ jobs over the years. If you can find the interest in a boring job, it makes the job easier, and allows you to do it better. Also, lack of interest destroys awareness, and can therefore kill you.

( I was once working on a financial audit for a North Sea Oil platform, a very boring job. I spotted a name with initials that seemed familiar. I decided to  watch out for duplicate names and found quite a few who had been working for different companies at the same times. One had even been employed by six different companies during the same period and had claimed full wages from all companies plus six sets of expenses. He was quietly fired, because of the clients embarassment.)

Always remember that if you are the senior engineer in any situation, you carry the responsibility for safety. You should therefore always be aware of the overall safety situation.

The Engineer.

This is a job description. This is the engineer in overall charge on any job. He should be fully knowledgeable of all aspects of a job including all the different trades involved. He may have many specialist senior engineers under him such as civil, mechanical, electrical, structural, marine, electronic, chemical etcetera. He must know enough to be able to verify that all trades have carried out work to a satisfactory standard from foundations to electronics and all trades between. He must also be conversant with contract law, finances and quantity surveying, because cost over-runs will normally be blamed on him.

He must also be handle labour relations problems, (generally by ensuring that there are none), and must be pleasant but firm with contractors management, and in many cases, his own management.

He cannot claim that ” he was told that it was OK”. it is his responsibility.

Engineer is a profession. It is probably the only profession in which, if you make a mistake, other members of the profession will tell you so, and in less than a gentlemanly way. Therefore sort out mistakes quickly or admit that you have made a mistake quickly. The engineer generally has no back-up to rely on, he is on his own.

Bearing all this in mind, it is not surprising that he is often referred to as “that Bloody Engineer”.

Engineering Trades.

Speciality Engineer. Must be able to design, supervise construction  and commission plant and equipment within their speciality.

Design Engineer. Normally refers to office based senior designers.

Draughtsman. The primary starting point for engineers, starts at detailing drawings, then detailing designs then design.

Machinist. Operating machines such as lathes, milling machines, grinders etcetera during manufacture of equipment.

Welder. All types of hand welding requirements. Does not normally include jig welded jobs.

Fitter. Assembly of products, normally on site. Normally prefixed by particular trade, such as pipe-fitter.

Mechanic. Assembly of machinery and equipment. Normally includes disassembly, fault finding and repair.

Rigger. Normally involved in the movement and setting up of very heavy objects.

Electrician. Carrying out installation of electrical equipment and cabling.

Structural & Civil. Covers many trades such as steel erectors, concrete, roadworks, drainage, sewage, paving, roofing, brickwork, cladding, insulating etcetera.

NOTE; There is much multi-discipline among trades. A fitter could also be a welder, rigger and machinist or any combination. This depends on the skill level of individuals. In the mills there was a a job title ‘Millwright’. this was the equivalent of engineer because he was in charge of all mill engineering functions, from civil to electrical. (Textile machinery is the most complex machinery ever invented.)

NOTE:  There are many people who claim to be engineers, but unless they can show the knowledge, skill and experience of design in their subject they are not qualified to be engineers.

Brian Williams – Author

The Design of Space Craft.

This post was  triggered by the following BBC report.

What should spaceships look like?

http://www.bbc.co.uk/news/magazine-14291992.

Science fiction (SF) has always fascinated me since I was a child. It is the type of fiction that opens the mind of the reader to concepts that are far outside the mundane realities of everyday life. Many of the SF writers also have an impressive grasp of psychology that could make other main-stream writers envious.  Note that there is a considerable difference between SF and Science fantasy in that SF writers tend to remain within the realms of scientific possibilities whilst science fantasy writers tend to wander into the areas of the ridiculous.

Science fiction illustrators nearly always produce artwork that is total fantasy in having no scientific basis. This is particularly obvious in their portrayal of spacecraft. The designs are generally totally unworkable as spacecraft and are mainly just strange shapes full of odd bits stuck on to make them look more ‘scientific’.

The design of the “Starship Enterprise”, the most famous spaceship design ever produced, would be be totally useless for space flight outside the influence of a gravity source.  Note; I am not a ‘Trekie’ so I am expecting lots of repudiations of my comment.

Why is this?

It is the same reason that bullets, war-shells, guided missiles etcetera all have symmetrical shapes. This allows balance in the forces acting.

Even the spin on bullets is there to there to counterbalance any imperfections in manufacturing that would cause them to deviate from their planned trajectory.

Aircraft have all sorts of imbalanced forces operating on them such as tail fins, landing gear, wing tanks, outboard weapons systems, etcetera that all affect the flight of the aircraft. However gravity exerts a major force that means that providing the imbalances are equal on both sides of the vertical plane, they do not upset the handling too much whilst travelling horizontally.

In space flight outside gravitational force, even slight imbalances become more serious. During acceleration the power must be applied through the centre of mass and in the direction that you want to travel. Any slight variation in the centre of mass will cause the spacecraft to rotate. If it rotates by I degree in the first second of a 10 second ‘burn’ it will rotate by 10 degrees (Approximately) during the 10 second burn.

To prevent this from happening a compensating force will be required. which wastes fuel.

How would the pilot know exactly where the centre of mass is? Generally he wouldn’t know, he would only have a calculated location. If a pilot put out his hand to operate a control, this would change to centre of mass of the spacecraft. If you had people walking about this would cause the centre of mass to continually change.

Let us now consider the starship Enterprise. Let us assume that it has lots of computer equipment to handle variations in the centre of mass and everyone on board is tagged to allow the computer to be aware of their locations.

The shape of the enterprise is quite pleasing and is not embellished with too much external junk. It could fly in Earth’s atmosphere or under a gravitational force. However, the position of it’s drives means that it would be impossible for the force to act through the centre of mass. It would need a large amount of energy to correct the imbalanced forces attempting to spin the spacecraft.

Another major problem with shapes of spacecraft designs is that they are not streamlined. If space was a total vacuum then the shape would not matter if the driving force operated through the centre of mass. However, space is not a vacuum and therefore there is something there to cause resistance. Due to the non-streamlined nature of most designs this resistance of the various ‘stuck on’ appendages would cause deviations in the path of the spacecraft.

Author

Brian Williams

Understanding Mathematics

Understanding mechanics is nothing to do with mathematics, it is the reality of what is actually happening and why it is happening?

OR

This post is really nothing to do with mechanics because mechanics is about reality?

In fact I will attempt to explain the roll of mathematics in relation to reality.

There is a series of pet food advertisements on British television, in which the animals (cats or dogs) state  that “you should read the instructions yourself because I cannot read”. However, earlier adverts had a situation in which the animals had to say that they could not count, but these adverts were quickly dropped. I would imagine that the company received thousands of letters pointing out that animals can count.  This was my immediate reaction on first seeing the advert. Sad really, that the company knew so little about animals.

Natural arithmetic is addition, subtraction, multiplication and division. Many animals have the inborn ability to carry out simple examples of these arithmetical functions.

Arithmetic

Addition and subtraction.

Addition and subtraction are fairly simple for animals, they check their young every few minutes and know exactly how many they should have (addition) and how many are missing (subtraction).   Our last dog, Mandy, when receiving ‘treats’ , would stay still until we had scattered the correct number of them, and then collect them together. If we did not throw the correct number she would nudge our legs to tell us that we had got it wrong. If we threw one more when we were two short she would nudge our legs again to tell us that we had still got it wrong.

Multiplication and division.

Division is ‘fractions’ . Obviously animals don’t calculate fractions that give an answer of less than one because there is no necessity for it in their lives. However, in some respects they can calculate fractions. Offer a dog the choice between a full shin-bone and half a shin-bone and it will select the full shin-bone. Which is the greater; one shin-bone or one shin-bone divided by two? [Which is the greater; 1 or 1/2 ?].

Now let us consider a far more difficult question. If we cut the shin-bone into three equal lengths A, B and C, which one would the dog select? The dog must work out which is the greater,  A, B or C. [Which is the greater 1/3, 1/3 or 1/3?]

We know from experience that the dog will not select B, it will select A or C. It is obvious that the human arithmetical notation is of no use to us in this case, but the dog would be able to make the correct selection. Does this mean that the dog is more intelligent than we are? No, it just means that the dog has more information than can be supplied by the human arithmetical notations. The dog works it out by logic.

Mathematics is a man-made tool which can be very useful. It is not a science. Like any tool it will do certain things very well.  and like any tool, if incorrectly used, can create disasters.

Although claimed by the physicists to be their specialised subject, (it should be, most physicists rely on a Mathematics Degree to get a job.), most of them only have knowledge of a small number of  the 1,000,s of formulae in everyday use. Most of the worlds formula were created by engineers. {Odd really, Einstein is famous for one equation that he got a Nobel prize for, (even though it was wrong), whereas I have created about 25-30 new equations over the years, all which have proved to be right. I once produced a new formula for working out escalation costs on Oil platforms. This caused great consternation to the oil companies and they spent many months attempting to discredit it. Obviously they failed because they had to pay in accordance with my new formula. This was quite a complex formula. On another occasion, determining  the cost of hiring ships, boats and rigs and their staff and operatives operating in the North Sea was quite a complex problem which even the suppliers had difficulty with.

In this instance I produced a simple formula that produced more accurate figures and only took about 30 minutes to  work out the total payments due each month. Obviously I do not hate mathematics, I just hate the misuse of mathematics, especially by physicists.

“Firstly, the abandonment of the ideal of a mechanical explanation of everything has eliminated a great deal of idle hypotheses. The properties of the fundamental entities of physics are now stated in the form of mathematical equations, instead of being ‘explained’ by a hypothetical mechanism.” From ” The Philosophy of Physical Science”, by Sir Arthur Eddington. This is the ‘Eddington’ usually quoted by physicists when they are asked awkward questions.

Let us consider the first sentence. Modern physics is now almost entirely composed of ‘idle hypotheses’. Quarks, time dilation, rubber sheet universes, black holes, time travel, nuclear fusion, Hadrons, and now the God particle, are just a few of the ‘idle hypotheses’ that occupy the minds of the physicists.

Logic and Measurement.

Although the word ‘logic’ is commonly used when referring to mathematics, logic actually refers to reasoning whereas mathematics is simply a set of rules designed to make things simpler. (Yes I know, if you don’t like mathematics, then the last thing you would agree with is that it makes things simpler, but it does make things easier if you do like mathematics.)

Anyone who has suffered from bureaucracy will probably agree that rules are not always logical. The same problem exists with mathematics.

Let us say that we have 7 Leopards and 10 camels. Now torque is measured in pounds feet and is obtained (mathematically) by multiplying pounds and feet. We should be able to multiply leopards and camels to arrive at 70 cameleopards. (yes there is such a thing, its also called a giraffe).

Obviously we know from common sense and reasoning that this is a silly idea.

We can however multiply leopards and camels to arrive at 70 animals, but this is no more logical. This is because you cannot multiply real objects by real objects.

You can add camels and leopards to get a total of animals.

A lot more to come on this but not yet.

Author; Brian Williams

Prams – Design Gone Mad?

I was about 4 years old when I first learned to push a pram properly. I am not talking about a push-chair, those were easy to handle, even at 18 months old. I mean the old carriage built prams with the big wheels that normally ended up on trolleys and go-carts. After I had struggled for a few days I finally passed my test and my mother allowed me to transport my baby sister without having her guiding hand on the pram handle. After a week I could set the parking brake and just about put the hood up if it was raining. This was not easy because to me this pram was huge, I could only see my sister by standing on tip toe.

69 years on I see adults struggling with pushchairs, (yes, pushchairs), that have been made using antiquated supermarket trolleys as the design standard. They are unwieldy, overweight and worse than supermarket trolleys for steering. They are frustrating to parents, take up too much space (at home and in the car), are overpriced and worst of all, are dangerous. Trapped fingers, broken nails, and like supermarket trolleys, are not interested in where you want to go.

60 years ago push chairs went exactly where you wanted them to go, they were light, they were cheap, they folded up neatly and they were safe.

Why?

Apart from the fact that that there is ‘Fashion’ to blame, the main problem is that nowadays knowledge and experience are ignored in favour of gimmicks. Every possible design of the pram was tried out in the 18th and 19th centuries. The carriage pram and the basic design of the push-chair were confirmed as the optimum for easy handling by young women (and 18 month olds).

The most important basic design detail was that ‘no steering aids’ gave the best steering. Sounds silly but its true.

Four fixed wheels gives a stable platform but also ensures that the pram travels in a straight line. Try pushing a modern push-chair in a straight line. As much energy is wasted in keeping to a straight line as is used in pushing the pram. (Just like the supermarket trolley)

A slight pressure on the pram handle and the front wheels lift off the floor. The pram can now rotate freely on two wheels and will ‘turn on a sixpence’. If you push a pram with 4 fixed wheels along a 400 yard pavement you will probably have to make the occasional adjustment to it. Forgotten your purse? Slight pressure on the handle, swivel round, release pressure, and your on your way back.

Four fixed wheels gives you total and easy control.

I have little doubt that the modern push-chair was copied off the supermarket trolley. Unfortunately the supermarket trolley is designed to carry heavy loads and therefore cannot use four fixed wheels. Some Do-It-Yourself stores have adopted the principle of the original pram in having two main load bearing wheels to enable easy steering. Unfortunately, these are normally fitted with castor-wheels at both ends, so you are left with a trolley that is easy to turn but won’t travel in a straight line.

Note that supermarket trolleys are based on factory trolleys and trucks which have to carry heavy loads. However, factory floors are normally flat and level. Although within the supermarket the floors are flat and level, the parking areas are not. In our local supermarket about 25% of the parking area is seriously sloped and sometimes it can take 4 or 5 attempts to get the trolley near to the car.

Author; Brian Williams

Understanding Vacuum and Pressure.

Understanding mechanics is nothing to do with mathematics, it is the reality of what is actually happening and why it is happening.

A vacuum is the complete absence of any gas or any other substance that could exert a pressure. A diamond in a vacuum chamber would not effect the vacuum in any way. Most other substances and gases would. Note: Total absence of pressure has never been achieved.

Luckily we very rarely have to consider such a tight meaning, because we are usually only considering a partial vacuum and its effects. Note that intergalactic space is not a vacuum, it is just at a much lower pressure than we are used to. If it was a vacuum our atmosphere would disappear like dust up a vacuum cleaner hose.

Note:- The reason we retain our atmosphere is that although you would expect it to be sucked into the partial vacuum of space, this is balanced by the gravitational force of the Earth acting on the gases forming our atmosphere.

I have worked on the design of pressure systems operating up to 30.000 pounds per square inch, (including B.O.P s and other oil and gas equipment, to be topical.)  but the problems of designing vacuum systems is a lot more difficult, especially considering we are only dealing with a maximum pressure difference of about 14 pounds per square inch. This indicates that something strange happens at low pressures.

Very low pressure systems are difficult to make and costly to run. The difficulty is due to the problems of sealing against leaks. Joints that seal perfectly at pressures of 10,000 pounds per square inch may leak like a sieve under very low pressures. Materials of the vessels  themselves will leak under vacuum, meaning that special materials must be used. Even with the best materials there is some leakage, which means that the vacuum pumps must be run continually to sustain any vacuum attained.

At low pressures, atoms and molecules that retain their stability at normal atmospheric pressure, begin to act oddly. As the pressure reduces they expand. (They are a in compressed state whilst a normal pressure.) This expansion means that the they take up more space in the containing vessel and also weigh less,. (The mass decreases, but please note that the individual atoms/molecules still have the same mass, but there will now be less of them taking up the same space, therefore the weight for each cubic centimetre is less)

Note:- Removing the atoms/molecules is rather like removing a flock of sheep from a field. Initially you have no difficulty removing large groups of them, but as the numbers reduce you have difficulty in rounding up the few remaining ones.

Why does a partial vacuum work better than pressure in certain cases?

Normally you are taught that a suction pump operates due to the pressure difference, and that by removing the pressure on the suction side, the the atmospheric pressure forces the gas or liquid to move. In general, this is a working principle that includes most normal situations.

However, consider a pipe with a suction pump at one end, the other end lying in a tank of sludge. When you switch on the pump the partial vacuum at the pump end allows the liquid at that end to expand and become lighter, making it easier to move and it will start to move through the pump. This expansion of the fluid will in itself cause some of the fluid to pass through the pump.

The expansion effect will pass back through the pipe until the effect of the reduced pressure reaches the sludge tank, when atmospheric pressure takes over. Even if you close off the pipe at the sludge tank end, the liquid expansion will still continue until you stop the pump.

This is why, when attempting to unblock the sink, it is the upstroke that finally clears the blockage, the expansion of the water molecules effectively breaking up the blockage. The downwards pressure of the plunger in most cases applying far more force on the blockage than the differential pressure set up by suction, but in most cases without shifting it.

Another apparently strange thing is that a car tyre with 30 psi pressure in it will stay up for years  (Mine don,t). However, if you place it in a vacuum chamber at (say) 8psi absolute, it will leak. This not due to the increased pressure difference, (cars tyres can take a considerably higher pressure than that without leaking) but due to the atom/molecule changes under low pressures.

Note:- To be effective suction pumps should be of the positive displacement type. Vacuum cleaners, water pumps etcetera. are only capable of creating a relatively small vacuum effect.  A sink plunger creates a far more effective vacuum.
A problem with many pumping systems which use non-positive displacement pumps is cavitation, which has the same cause, creating vapour or gas within the pump, which ceases to run correctly or even not work at all.

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The old washing machines that used a central paddle arrangement that moved one way and then the other way, depended on vacuum for their cleaning efficiency. When the paddles reversed direction a partial vacuum was created which sucked water through the washing. Later washing machines are unable to do this and although the wet washing gets moved about, only a very small amount of water actually passes through the washing. Unfortunately the old system generally required top loading which is difficult to fit in modern kitchens.

Also read Dinosurs and the Expanding Earth – 2 -The Earth Mechanics

Author – Brian Williams