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Technology

Grade 7

Working with wind and water

Module 7

Water-wheels

Background

The WATER-WHEEL was one of the first examples of a motor or a machine that could be operated by making use of running water. A water-wheel is made of a large wooden wheel with blades or paddles that turn on an axle. It utilises the force of running or falling water to make a machine work. The axle of the wheel is connected to the machine, and the power that is generated by the wheel is conveyed to the machine. A water-wheel is therefore an example of a wheel and an axle, because the force of the water on the blades causes a powerful propelling or driving force on the central axle.

The first kind of water-wheel was built in Greece in 200 BC. However, it was not satisfactory, because it turned on a vertical axle and needed fast-flowing water. Because it was small, the wheel generated only enough power for one family to grind their wheat for flour. Marcus Vitruvius Pollio designed a better water wheel in 35 BC.

There were mainly three types of water wheels with axles that turned horizontally. They were larger and could generate more power. One type, the undershot wheel , was built over running water. It had flat blades and the water ran along the LOWER PART or BASE of the wheel, retaining the same level all the time. The flow of the water against the flat blades at the base of the wheel made the wheel turn.

Undershot wheel

Another kind of wheel, the overshot water-wheel, had blades that were shaped like little bowls. These “bowls” could catch up the water that was fed to the wheel through a channel or trough. Thus the water cascaded over the blades from a trough ABOVE the wheel. The weight of the water in the bowls caused the wheel to turn faster than the undershot wheel that was powered by the weight of flowing water. Therefore, in the case of the overshot water-wheel the water fell on the wheel from above and flowed away on ground level.

Overshot water-wheel

In a centreshot water-wheel the water struck the blades in the CENTRE of the wheel.

Centreshot water wheel

In a hydroelectric power station the water cascades through a pipe into a dam, and the blades of the turbines are made to rotate. The pressure caused by the cascading water rotates the wheel so that it rotates in the same way as the water wheel. The turbine supplies

the power for a generator that generates electricity.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Technology grade 7. OpenStax CNX. Sep 10, 2009 Download for free at http://cnx.org/content/col11032/1.1
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