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Historical Overview

8.1.1 Outline two types of energy.

Energy is classified as kinetic and potential energy.
Kinetic energy is the energy associated with a moving object, for example, a moving football, a speeding train, a waterfall or a rock falling from a cliff.
Potential energy is the energy in an object due to its position or the arrangement of its parts. It includes gravitational, elastic, chemical and electromagnetic potential energy.
Gravitational potential energy is produced when an object is lifted up and work is done against the force of gravity. As the object falls, potential energy is converted to kinetic energy.
Elastic potential energy is produced when an object (such as a spring or a rubber band) resists being stretched out of shape. The energy from the deformation of the band can be converted into kinetic energy and used to do work, for example, to spin a propeller or power a toy aeroplane.
Chemical potential energy is the energy that holds molecules together. Combustion, for example, of fossil fuels, releases the energy, which can be used to do work.
Electromagnetic potential energy can be stored in a battery or supplied from a power plant, hydroelectric dam or windmill.
Thermal energy is the movement of molecules that make up the object. All objects possess thermal energy (even cold ones), since they have a temperature above absolute zero.

Activity: Find a design context for each type of energy mentioned above.


Kinetic and Potential Energy

Kinetic energy is energy of movement. A moving body has kinetic energy which in all but relativistic circumstances is proportional to the square of the speed. This energy is the least practical energy for conversion between different types of energy.

Potential energy is energy stored in a field. Gravitational potential energy is the kinetic energy that could be gained by falling from a certain height.

  • Until the object falls, that energy is stored in the gravitational field. Many types of potential energy are actually just different manifestations of electromagnetic potential.
  • Chemical energy is electromagnetic energy stored in a compound that could be released in a reaction. Electrons are held in a high potential energy level and lose energy in the reaction as they "fall" toward a lower potential. This energy is harnessed by letting it "fall" through a wire and do work on its way through.
  • Elastic energy: The electromagnetic bonds between the atoms and molecules in the solid are strained, this strain on the electromagnetic field is manifested as an electromagnetic potential which is changed into kinetic energy at the first possible chance. Electromagnetic energy can be converted from kinetic energy through the use of magnets, electricity, and the magnetic aspect of electricity.
  • Thermal energy:kinetic energy of all the particles in a substance and is felt as heat. It can be calculated by adding all the kinetic energies of all the particles in the substance. This is the easiest energy to convert to and is usually considered wasted energy. 0K is the point at which all molecular and atomic motion stops, it is impossible to reach as there is no insulator good enough to completely stop the flow of motion.
  • Nuclear potential energy: this is the energy held in a strong nuclear field and is released when a nucleus is split in a nuclear reaction. It is significantly stronger than the others and is the only one with a noticeable E=mc^2 effects due to lost mass in the field.

8.1.2 Describe how human muscle power was the only source of energy for (craft) production until the Industrial Revolution.

Before the Industrial Revolution

Man power was used from the beginning of time, until the industrial revolution, which brought machinery that would replace human labour, in order to make production more efficient.

  • People could only depend on their muscle power and the muscles of domesticated animals like horses.
  • The tools that were used in these energy resources include: axes, ploughs, wagons and carriages, windmills, and sailing ships.
  • Muscle offered sources of energy that are still accessible to us and are still used to power simple machines in several parts of the world today.

8.1.3 Describe how development of machines based on flowing water led to a revolution in production.

The water wheel enabled the harnessing of energy for production. However, the water wheel had a fixed location next to a fast-flowing river and so lacked flexibility.

Hydro-power is a power that is derived from the force of moving water and humans have been harnessing water to perform work for thousands of years. The Greeks used water wheels for grinding wheat into flour more than 2,000 years ago, in the Roman times they used Hydro-powered machines like watermills to cut timber and stones. Watermills, textile machines, sawmills and other machines powered by the flow of water were widely used until the steam engine was developed. Factories eventually developed thanks to the watermills but it was not large scale. It had to be placed next to a river river or any water source and also the water flow wasn't always strong enough for mass production or heavy duty work. The hydro power went away with the innovation of the steam engine but it can still be used as a source of energy in modern times.

8.1.4 Describe how the invention of the steam engine and the use of steam as the basis for the operation of machines led to a large increase in scale of production based on coal.

Steam power is more efficient than water power, but still only 30% of the energy produced is converted. The advantage of steam power is that it is more movable and therefore flexible.
Consider the impact of the steam engine on the mechanisation of the cotton industry

Steam power's importance in the Industrial Revolution.

  • steam power was used to drive machines;
  • allowing for mechanisation;
  • and mass production;
  • faster production than when human powered;
  • as machines were more powerful than humans;
  • and more complex processes could be used;

Coal's importance

  • coal was used to create steam power, the basis of mechanisation;
  • and coal is used to create electricity the basis of automation;
  • coal was an abundant global resource during the industrial revolution and 20th century;

Steam power began during the modern era in the eighteenth century by Thomas Savery and Thomas Newcomen. The steam power eventually proved more flexible and economically efficient. Coal mining, the iron industry, and steam power created a new era in steam technology and during the 1800 steam energy plus waterwheels to power English textile mills. By the nineteenth century, steam energy improved enormously. History of power/energy starting from water, from the Franklin institute.

8.1.5 Explain how the development of electricity led to a technological revolution and an increased volume of production.

Faradays discovery of electromagnetic induction and the invention of the dynamo allowed the energy from coal or fast-flowing water to be converted into electricity. As a result, the electricity industry was established, with a sophisticated infrastructure enabling a new generation of electrical machines and electrical products. Factory production and the development of assembly-line arrangements enabled the development of a vast range of cheaper products.

Faraday discovered that a changing magnetic field creates an electric field and (due to Galilean relativity) a changing electric field causes a magnetic field. This has been harnessed by dynamos and electric motors, in a dynamo, a coil is turned inside a magnetic field, generating an electric current in that coil (due to the changing magnetic field creating an electric field, moving the electrons which makes current) which can then be used for different electrical appliances. An electric motor is just the opposite, the moving electrons create a changing magnetic field which causes the shaft of the motor to turn.

8.1.6 Identify uses for the electric motor in industrial production.

Consider the application of rotary motion in drills, saws, lathes and belt systems.
Lathe Drill Press
Saws Belt systems

Electrical motors uses electrical energy to produce mechanical energy. Electrical motors are most commonly used in household appliances such as refrigerators, fans, vacuums, pool pumps, etc. also all electronic devices such as DVD players, computers, etc. have electric motors.

Today electric motors are being used for more sophisticated things such as hybrid cars.

Example of electric motor

8.1.7 Explain how the production and distribution of electricity led to large-scale energy usage, security of supply and the geographical spread of production away from the source of energy supplies.

The electrical distribution network and grid system allowed industry to move away from the source of the fuel supply.

Electric power transmission allows remote energy sources (such as hydroelectric power plants, wind turbines, nuclear power plants, etc.) to be connected to consumers in population centers, allowing utilization of low-grade fuel resources such as coal and natural gas that would otherwise be too expensive to transport to generating facilities. Centralized power generation became practicable when it was possible for alternating current power lines transporting electricity at very low costs across great distances.

The electrical power industry is divided into four processes; 1) electricity generation such as a power station, 2) electric power transmission, 3) electricity distribution and 4) electricity retailing. It is common for electric power companies to own the whole infrastructure from generating stations to transmission and distribution infrastructure; an example of this process is in this link.

A power transmission network is referred to as a "grid". Multiple redundant lines between points on the network are provided so that power can be routed from any power plant to any load center, through a variety of routes, based on the economics of the transmission path and the cost of power. Much analysis is done by transmission companies to determine the maximum reliable capacity of each line, which, due to system stability considerations, may be less than the physical or thermal limit of the line. Deregulation of electricity companies in many countries has led to renewed interest in reliable economic design of transmission networks. Wikipedia article on electric power transmission

8.1.8 Explain how the development of localised, portable sources of electrical energy in the form of batteries changed the nature of energy usage and the development of new types of products.

Consider portable radios, mobile phones, and other portable electrical and electronic products.
This development has now added a whole new consideration for designers when designing a new product. It has opened a whole new range of opportunities for innovations and inventions to take place in order to create a safer more efficient society.
  • Mobile phones are now widely used and have, not only increased society's sense of safety when people are out alone, but it has also been the cause of a variety of innovative ideas being spread around society.

References

Numbered list and italicised paragraphs are excerpted from Design Technology: guide. Cardiff Wales, UK: International Baccalaureate Organization, 2007.

Images are clickable links to its location.

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Page last modified on September 03, 2013, at 07:47 PM