techdirections May 2010 : Page 31
MINI PROJECT Check out this free techdirections’ Mini On-Demand Classroom Project (Regular price $2.95) In addition to Mini Projects, the On-Demand Classroom Projects line includes over 150 full-size projects for only $6.95 each! Written by teachers for teachers, On- Demand Classroom Projects not only make learning fun for your students, but allow them to better understand how technology relates to the real world. Available in a wide variety of subject areas, from applied academics to woodworking. Order online and use them today! Simply duplicate and use for as many students— and for as many times—as desired. Our high- quality activities save you time and are priced with teacher budgets in mind. Projects include teaching tools such as procedures, vocabulary words, quizzes, photos, illustra- tions, and much more. Check them out today! www.techdirections.com/ projects.html www.techdirections.com Larry Roberts taught technology education at High- lands Middle School, Kennewick, WA. He has won nu- merous awards in recognition of the excellence of his teaching and programs. POWER & ENERGY 31 I By Larry Roberts robela@ksd.org N this project, students will first learn the basic parts of a turbine and the ways in which turbines are used. Then, the history of turbines is presented as well as how tur- bines work, the different types of turbines, and future uses of turbines. A 10-question quiz is included to test students’ knowledge. The activity culminates in students building two turbines (one with 8 blades, the other with 16 blades) using paper and tape. They will then test their turbines in a teacher- or student-built hydroelectric dam mock-up and measure rpms using a fan and strobe light. FREE Energy, Power, and Transportation Turbines
Energy, Power, and Transportation: Turbines
IN this project, students will first learn the basic parts of a turbine and the ways in which turbines are used. Then, the history of turbines is presented as well as how turbines work, the different types of turbines, and future uses of turbines. A 10-question quiz is included to test students’ knowledge.
The activity culminates in students building two turbines (one with 8 blades, the other with 16 blades) using paper and tape. They will then test their turbines in a teacher- or student-built hydroelectric dam mock-up and measure rpms using a fan and strobe light.
Larry Roberts taught technology education at Highlands Middle School, Kennewick, WA. He has won numerous awards in recognition of the excellence of his teaching and programs.
THE word turbine comes from the Latin turbo, the word for a spinning object. Turbines are rotary engines that convert the kinetic energy (energy of motion) of a horizontal or vertical moving stream of water, steam, or gas into rotational mechanical energy.
The basic parts of a turbine are propellers or blades, an outside band, and an axle. The spinning motion of the axle may operate machines, compressors, electric generators, or water pumps.
Generators driven by turbines produce electricity used to light homes and run factories. Turbines that power water pumps irrigate farms. Turbines also turn the propellers of ships, and they are an essential part of jet airplane engines.
History The oldest and simplest form of a turbine was the water wheel, a European invention for grinding grain.
It consisted of a vertical shaft with a set of paddles positioned in a flowing stream.
The transition from water wheel to turbine is largely a simple change of design. The first attempt to design a better water wheel took place during the 19th century.
Curved blades increased efficiency to 70%.
Turbines used in dams were also developed during the 19th century. Water is pulled through a pipe by gravity from a reservoir to a nozzle. The nozzle produces a powerful jet of water directed onto curved blades that turn the turbine.
How Turbines Work Turbines are enclosed in a casing. Nozzles called guide vanes aim fluid (water, steam, or hot gas) at the blades and adjust its speed. The casing holds the fluid against the turbine so that it loses none of the energy.
As fluid passes through a turbine, it pushes against the blades and causes the axle to turn. When the axle rotates, its power and momentum transfers through a THE word turbine comes from the Latin turbo, the word for a spinning object. Turbines are rotary engines that convert the kinetic energy (energy of motion) of a horizontal or vertical moving stream of water, steam, or gas into rotational mechanical energy.
Energy, Power, and Transportation: Turbines series of gears to an electric generator, air compressor, or other machine.
Some turbines have only one set of blades. Others have 50 or more. Multiple sets of blades increase the efficiency of the turbines, because each set removes more energy from the moving fluid. In a turbine with more than one set of blades, the blades are mounted on a common axle, one set behind the other. This type of turbine is called a multistage turbine.
Types of Turbines Turbines are classified by the fluid that turns them.
There are four main types of turbines.
Water turbines are called hydraulic turbines. Water turbines are driven by water stored in a reservoir behind dams.
Steam turbines are run by steam. A boiler burning coal, oil, or natural gas produces steam. Nuclear power plants produce steam by splitting atoms in a reactor.
Gas turbines burn oil and natural gas. Instead of using steam, gas turbines use the hot gases to turn the turbine. Power electric plants, ships, race cars, and jet aircraft use gas turbines.
Wind turbines, also known as windmills, are turned by the wind.
Future Use of Turbines Technology has developed enough now to support an undersea turbine farm. As a first step, a tidal stream generator has been installed in Strangforn Narrows in Northern Ireland; other undersea turbine farms are in the planning stages.
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