The Way Things Work

What I would like to do today is to try to instill in readers an appreciation for how the everyday technology all around you actually operates. Such an appreciation will open up a fascinating new world. This can be read in conjunction with the posting on this blog, "Scientific Literacy", which is about everyday science and mathematics, while this blog is about everyday technology.

Iron is a strong metal. But it can be made even stronger by adding carbon to it. Carbon atoms mixed in with the iron atoms add strength to the metal. Iron with carbon forms what is known as steel. We can craft steels with a wide variety of properties, according to the percentage of carbon that is added. As we add more carbon, the steel produced becomes harder, but also more brittle. Other metals can be added also. Stainless steel, for example, contains chromium and nickel, as well as carbon. Silicon, tungsten, vanadium, manganese, and molybdenum are often added to steels. Steel will rust and for this reason it is often coated with zinc, particularly sheet metal. This process is known as galvanizing.

Aluminum is known for it's combination of lightness and strength, it's most important use is in aircraft construction. It is actually a very common metal. Clay often contains aluminum, meaning that there is a lot of aluminum within bricks. However, it was late to be used by humans because it cannot be separated from it's ore by smelting like other common metals. Aluminum is extracted by electrolysis, and did not become widespread until cheap electricity became available.

If you have a summer barbecue, you probably notice that charcoal produces practically no smoke at all. Charcoal is produced by charring wood in a kiln without any air present. The result is that the smoke-producing compounds in the wood are removed, so that you can have a smoke-free barbecue.

Suppose that we have a cable hanging between two supports, such as a telephone or electric wire strung along poles. Now suppose we put some slack into the cable so that it hangs down in the middle. The cable will form a shape known as a "catenary", it is close to an even curve but not exactly the same thing. The catenary shape is important because it is the strongest curve when it comes to building bridges. It is used especially in the type of arch bridges where the road is directly on top of the arch, such as the Grand Island Bridges in the Niagara Falls-Buffalo area.

An optical microscope can never magnify more than about 1400x. This is simply because of the limitation imposed by the wavelength of light. We can never actually see atoms for this reason. Images have been taken of atoms using an electron microscope, this gets around the limitation by using a beam of electrons to form an image, instead of visible light.

As long as we measure time in seconds, 16 feet (4.876 meters) is a very significant distance on earth. A small, compact object will fall at 32 feet per second squared. The thought occurred to me one day that we could thus easily measure between altitude and falling time. To measure altitude, take the time in seconds that it takes such an object to fall from the height. Then, square it and multiply it by 16 feet. If we are dropping a compact object, such as (unfortunately) a bomb, from a known altitude and want to know how many seconds it will take to reach the ground, simply divide the altitude by 16 feet and take the square root of it. I explained this in my book "The Patterns Of New Ideas", and proposed that 16 feet be known as a "grav", short for gravity, because it would be such a convenient measure of altitude.

Electromagnetic waves tend to be reflected by objects which are comparable to the wavelength of the waves in size. Have you noticed that if you are listening to the radio in a car, and you pass under a bridge, longer waves of a frequency arounf 1 MHZ or so will fade until the bridge is past. But shorter waves of a frequency of around 100 MHZ, or so, will not. This is because the longer waves are reflected by the bridge, but are too long to be reflected around under it, while the shorter waves will be reflected all around under the bridge and do not fade. In North America, the longer waves are usually known as AM, for amplitude modulation, and the shorter waves as FM, for frequency modulation. This refers to the way that the radio signal is encoded onto the carrier wave. A MHZ of frequency is a megahertz, or million cycles per second. Since electromagnetic waves travel at a fixed velocity, what we perceive as the speed of light, obviously the lower the frequency the longer the wavelength.

Long-wavelength radio waves can be reflected by the ionosphere, in the earth's upper atmosphere. This means that these waves can travel long distances by using the ionosphere as a waveguide. The ionosphere is especially reflective at night. Have you ever noticed that when a radio is tuned to longer waves (such as AM) at night, radio stations from far away can be received? When I used to listen to music, I (in New York State) would often scan the dial at night to see what radio stations in Ohio, Indiana and, Michigan had to offer. This is not true of shorter waves, such as FM and television. These waves can only be received as far as the horizon, because they are not reflected back by the ionosphere and continue into outer space. This is why it is ideal to place an antenna for shorter wavelengths as high as possible, so the horizon will be further away. The only way around this limitation of shorter wavelengths is to use a satellite to reflect or rebroadcast the signal. If a satellite is placed at an altitude of 22,300 miles (about 36,000 km), it will orbit at the same speed as the earth rotates, and thus will remain overhead. This is called a "geostationary" orbit.

It is important to know the length of a wave of the frequency that we are dealing with because the ideal antenna, for both broadcast and reception, is one half of the wavelength. The reason for this is that the electrons go from the base of the antenna to the top, and then back down, with each cycle. We get the wavelength by dividing the speed of light by the wave frequency. In practice, a long wave receiving antenna is often a coil of wire within the radio. A familiar whip antenna is for shorter wavelengths.

The idea of awnings over windows and doors that face the sun in temperate climates is for the hot sun to be blocked by the awning when it is high in the sky during summer, but for the warming sunlight to be allowed in when the sun is low in the sky during the winter. In the same way, evergreen trees can be placed on the north side of a property to shield against the cold winter wind while deciduous (leaf-bearing) trees are placed on the south side. The leaves of these trees provide shade in summer, but their leaves fall off to allow the warming sunlight through in the winter.

The difference between light from a laser and ordinary light is that laser light is monochromatic. That is, it is of one single frequency of light. Ordinary light is most often a mixture of many frequencies. Also, the laser light is aligned so that it's wavelengths are always coordinated "in step". The crests of all of the waves strike the target at the same time, and the troughs of the waves do the same. Any ordinary light has force in it, but the force is dissipated by the crests and troughs of the waves being "out of step" with one another. Obviously, this "in step" coordination is only possible if the waves are of one single wavelength. White light is actually a mixture of all colors (colours), and for this reason you will never see a white laser.

Molecules of soap act as bridges. One end of the molecule bonds with water, and the other end bonds with dirt. This helps the water to carry away the dirt.

Water molecules are polar, this means that one side of the molecule is more negatively-charged, while the other side is more postitively-charged. So, if we put some food containing water in a chamber, and then bombard it with electromagnetic radiation from varying directions so that the molecules of water flip over repeatedly at a high rate of frequency, the food will be cooked by the heat that is produced by this movement. this is what we call a microwave oven.

A smokestack pull smoke up into the air by use of air pressure. The pressure of the weight of the atmosphere is highest at ground level, and progressively lessens as we gain in altitude. This means that there is less pressure at the top of the smokestack than at the bottom. So, air is pulled from the bottom to the top and the smoke is pulled with it.

When refraction of light takes place, the bending of the light as it passes through water or glass, the shorter wavelengths are bent more than the longer wavelengths. This is why a prism breaks the light down into it's component colors (colours). British street lights are usually orange because orange is a longer wavelength of light, and this light will be refracted less by the droplets of water in fog.

Direct current is just what it says, a direct electric current from a negative to a positive terminal. The negative terminal is so-named because it loses electrons, while the positive terminal gains them. Alternating current is, as the name implies, a current in which the negative and positive terminals continuously alternate with one another so that the current flows first in one direction, and then the other. The thing that is useful about alternating current is that it can easily be passed through a device called a transformer to manipulate it's voltage and current. Voltage (measured in volts) is the pressure driving the flow of electricity, and current (measured in amperes) is the actual volume of electrons that are moving to form the current. The voltage multiplied by the current in an alternating current must always remain the same, but the transformer can raise the voltage at the expense of the current, or vice-versa. This is valuable because the transmission of electricity over long distances of wire is much more efficient with high voltage. The voltage can then be stepped down for use in homes and buildings. This cannot readily be done with direct current, at least not efficiently. Thomas Edison was looking at direct current for large-scale electric usage, but it was Nikola Tesla who prevailed with alternating current. On issue that arises with alternating current is that there are different frequencies (or cycles) that can be used. Anyone who travels often between countries knows that an electrical device from one country will not necessarily operate on the different cycle in another country, at least not without an adapter.

An electric current, where alternating current or direct current, can produce heat and light by passing through a resistance to the flow of current. A wire of moderate resistance gets hot when current passes through it, and a wire of very high resistance glows. This is the basis of the light bulb. Light can also be produced by passing a current through certain gases, most notably neon.

Radio waves are produced by generating a high-frequency alternating current, and then passing it through an antenna so that it radiates outward. Radio is usually used to carry information, but can also be used as a ranging tool. Remember that radio waves tend to be reflected by objects that are comparable in size to the wavelength of the waves. Bouncing radio waves off of objects is known as "radar". This is an acronym for "radio detection and ranging". Waves similar in length to that of rain drops will show where the weather is. Longer waves will be reflected from the metal surface of aircraft, and can be used for air traffic control. We know that waves travel at the speed of light so all we have to do is send out the waves from a directional dish antenna and then time how long it takes for them to be reflected back to the antenna.

Airplanes (aeroplanes) can fly because of the shape of their wings. The wing surface is flat on the bottom, but curved on top. This shape is known as an airfoil. As the plane moves forward, and air passes over the wing, the air above the wing must travel further than that below the wing. This means that it moves faster, and the result is lower pressure above the wing than below it. This pressure differential increases as the plane gains speed, and the air moves faster over the wing. When the pressure differential exceeds the weight of the plane, it lifts off into the air. The wing is usually tilted slightly upward, to increase lift, but the aircraft cannot climb at too steep of an angle, or this lifting power will be negated and it will go into a stall. This means that aircraft that must be able to climb rapidly, like military planes, are better off without this upward tilt to the wings. A propellor operates on a principle similar to that of the wing so that it is pulled forward into the air, and brings the plane along with it. Propellors require the dense air at relatively low altitudes, so that propellor-driven planes have a certain height ceiling. Jets actually operate better in the thinner air at high altitudes because there is less air resistance to high-speed flight.

For small-scale electric usage, a battery generates a current by a chemical reaction. Batteries always provide direct current. But for large-scale electrical applications the current is generated, usually by converting mechanical energy of motion into electrical energy. A relative motion between a magnet and a wire will produce current. Metals tend to be composed of structural units called crystals. The atoms in these crystals share the electrons in the outer atomic orbitals. If there is movement of a magnetic field, the magnetic lines of force will cause electrons in the wire to move beyond their home crystal. Thus, the spinning of a magnet in a coil of wire will generate a useful electric current. The generator can be configured to produce either direct current or alternating current. A generator is called an alternator if it produces alternating current. All we have to do is to reverse this order, so that the current in a coil of wire causes a magnet to spin, and we have an electric motor which converts the electrical energy back into mechanical energy. Electric motors are configured to operate on either alternating current or direct current.

No matter how complicated computers can seem, what it all comes down to is that if we can store simple bits of information, magnetic particles that are placed as either on or off, 1 or 0, and we have many millions of such bits, we can store a vast amount of information by encoding it into this binary system (binary means that there are only two possibilities). If we refer to eight such bits as a "byte", that means that each byte can have 256 possible combinations, because 2 multiplied by itself eight times is 256. We can encode all of the upper and lower case alphabet, as well as numbers, puncutation and, various control signals into these 256 possible combinations in the byte. This byte code system is known as ASCII, and is the foundation of computing. Everything else about computers is mere details.

You may see towers with large tanks on top in various locations. In cities, such tanks may be on top of buildings and in hilly areas, they may be at the top of a tall hill. These tanks are where your water pressure comes from. Water from treatment plants are pumped into these tanks then, when you turn on the water, you get the pressure from gravity. The name of the town is often written on such water pressure tanks. One nearby tank is painted in a red and white checkerboard pattern, because it is near the airport and pilots can use it as a visual reference point.

Old steam engines were really simple devices. Steam pressure would be built up in a chamber called a "steam chest". There would be two openings from the steam chest into a cylinder with a piston, but a mechanism made it so that only one of the openings would be open at any one time. The steam from the steam chest would go through the first opening and push the piston down through the cylinder. But when the cylinder reached a certain point, the first opening would be closed and the second opening, on the other side of the piston, would be opened. The steam would then flow through that opening, while pushing the piston in the opposite direction, until the piston reached the point where the mechanism closed the second opening and re-opened the first opening. Thus, the steam produced a reciprocating motion in the piston which can be used for such tasks as driving a locomotive.

Jet and rocket engines operate on the action-reaction principle. Fuel is sprayed into a stream of incoming air and ignited. The exhaust goes backward, and pushes the craft in the opposite direction. The main difference between a jet and a rocket is that a rocket carries it's own supply of oxygen or oxidizer, while the jet takes in air from the outside as it moves forward.


What would a discussion of everyday technology be without the internal combustion engine? The remainder of this posting is about internal combustion engines.

When you start your car, an electric motor, called the starter, turns a heavy metal wheel, known as the flywheel. This gets the engine started, and the momentum of the flywheel keeps it going.

The flywheel is attached to the crankshaft, a central axle around which the engine is constructed. The turning of the crankshaft causes a smaller parallel axle, the camshaft, to turn. The two shafts are connected by a belt or chain. The connection between the two must be precisely set, and is known as the timing of the engine. The camshaft, like the crankshaft, is not a straight axle it is crafted to sequentially open ports in the cylinders of the engine.

Each cyclinder in the engine has two ports, one to take in it's share of the fuel-air mixture coming in from the air filter and fuel injection system, and one port to let exhaust gases flow into the exhaust manifold after combustion has taken place. The engine may have from four to eight cylinders.

Combustion in the cylinders is brought about by a spark from a spark plug after the fuel-air mix has been compressed by the movement of the piston in the cylinder. This combustion pushes the piston forcefully, and is where the power in the engine comes from. The pistons connect to the crankshaft, and the movement of the pistons causes it to turn at high speed. The spinning crankshaft, with the flywheel turning along with it and keeping the engine running, is what turns the wheels of the car, after the spin of the crankshaft is redirected by the car's transmission.

The timing of the spark in the cylinders, as well as the opening of the intake and exhausts ports at just the right moment, is accomplished by the rotation of the camshaft, connected to the crankshaft. There are four strokes, or movements, of the piston in each engine revolution. Two are in one direction, and two in the other direction.

First, the piston moves away from the ports, with the intake port open, and the resulting partial vacuum pulls fuel-air mixture into the cylinder. Second, the port is closed by the rotation of the camshaft and the piston moves in the opposite direction to compress the fuel-air mix. It is at this point that the spark plug is fired, and the fuel-air mix ignited. The resulting explosion pushes the piston back down in the cylinder, this is the all-important power stroke. Finally, the exhaust port is opened by the camshaft and the piston moves back toward the end of the cylinder with the ports, and pushes the exhaust out of the cylinder into the exhaust manifold.

The cycle then starts over again. Only one of the four piston movements actually provides power. The momentum to turn the crankshaft, which moves the pistons, for the other three movements comes from the other cylinders.

Also connected to the crankshaft, by a belt at the front of the engine, is an alternator or generator to generate the current to recharge the car's battery, which is necessary for the starter motor to initially turn the flywheel, and also to provide the current to produce the sparks for ignition in the cylinders. The current first goes through a coil, which acts as a transformer to high voltage, and a distributor to get it to the right cylinder at the right time. At least that was the way it was before each engine had a computer module.

Oil is necessary to lubricate the engine so that it does not destroy itself by friction, and also to absorb some of the heat. Even so, a cooling system is still needed which circulates antifreeze through the engine block and uses a radiator and a fan in the front of the engine to help dissipate heat.

In a front-wheel drive car, the front of the engine with the belts and turning end of the crankshaft will be facing the side of the car. The primary difference between gasoline (petrol) and diesel engines is that diesel engines do not use spark plugs, extremely high compression is all that is necessary to ignite the fuel-air mixture. Glow plugs in diesel engines are simply to warm the fuel-air mix when it is cold out, and are not the same thing as spark plugs.