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Technology

Grade 8

Structures

Module 5

Beams, pillars, struts, crossbars and anchoring lines

Activity 1

Beams, pillars, supports/struts, crossbars and anchoring lines:

  • The above are important parts of structures. They are used in buildings, bridges and other objects. The pipes forming the framework of your bicycle, for instance, belong to the category of beams.
  • The main function of beams is to bear a load. If the load is too heavy, the beams will bend. In the past, tree trunks were used to provide solid beams, but the cost and weight of these have necessitated the development of different forms of structures, made from a variety of materials, used as beams.

  • Pillars and lampposts are beams that are used vertically. Pillars are useful in buildings for supporting overhanging verandas. If the pillars do not have the capacity to bear the load, the building will collapse. We now and again read about buildings, e.g. shopping centres that collapse.
  • Brackets of some or other type are sometimes used to mount TV sets against walls. It will be clear to you that the TV set causes stress to the platform on which it rests, which actually can be classed as a beam. Being supported at one end only, such a beam is called a crossbeam. To keep the crossbeam in position, a strut is used as support.
  • Similar struts are used in tents and for power lines. In such cases, the struts may be cables and ropes.

  • This sketch shows how a learner reinforced his bridge (a beam) made of drinking straws, by means of a strut and string.

Assignment 1

  • Examine the following illustrations and describe the ways in which technology was used to solve problems occurring in different cultures.

Assignment 2

  • Refer to the following and describe the impact that technological development with regard to structures has had on the lifestyle of people.
  • Skyscrapers
  • Aeroplanes
  • Roof trusses
  • Railway lines and trains
  • Bridges
LO 3.2

Assessment

LO 3
TECHNOLOGY, SOCIETY AND THE ENVIRONMENT The learner will be able to demonstrate an understanding of the interrelationships between science, technology and the environment.
This is demonstrated when the learner:
indigenous Technology and Culture:3.1 compares how different cultures have solved similar problems and relates the differences to the culture and values of their societies;
impact of Technology:3.2 expresses and details opinions about the positive and negative impacts of products of Technology on the quality of people’s lives and the environment in which they live.

Memorandum

ACTIVITY 1

Allow learners to discuss beams, pillars, struts, crossbeams and anchor lines and to list examples. Let them explain where the stresses are exerted and what the application of a specific structure is, why it is suitable for the application and how it could be improved. In the case of a crossbar, the stress, for instance, is exerted below; a pillar bears vertical stress that is equally strong all over.

Assignment 1

  • It is important to use correct terminology when discussing examples:
  • Bow and arrow :Problem: It was necessary to hunt to get food. Animals could not be caught by hand. It became necessary to design a weapon.The bow and arrow as a structure: The string is used to exert the force of stress on the bow. The bending of the bow makes it possible to transfer this force to the arrow as the force of compression. The arrow, as a beam, causes the force to work in the direction of the arrow point to penetrate the prey.
  • CrossbowLike the bow and arrow, but more accurate and more powerful.
  • Shield and spearThe spear serves as a beam, which means that the force is exerted in the direction of the point, which can therefore penetrate the prey. The shield forms a shell structure, with the skin as shell and the wood as a frame.
  • SwordThe blade works as a beam.
  • Ordinary hutA shell structure, with the woodwork as frame and the grass as shell.
  • Rondavel and thatch-roofed housesLike ordinary huts, but with the clay forming part of the shell.

Assignment 2

  • Skyscrapers : larger numbers of people are able to inhabit a specific space. This facilitates urbanisation and makes demands on urban transport, sewerage, electricity supply, removal of storm water: problems that had to be solved by means of technology and have created job opportunities, which lead to further urbanisation.
  • Aeroplanes : great distances can be covered in brief periods of time, which means that both people and goods can be transported quickly. This, however, has implications with regard to pollution and the utilisation of natural resources. It also increases the tempo of living.
  • Roof trusses : For people who live in inhospitable climatic regions, roof trusses prevent roofs from collapsing when there are heavy snowfalls and hail.
  • Railway lines and trains : As with aeroplanes, but trains have also enabled people to spread civilisation across the globe.
  • Bridges : as with aeroplanes and trains.

Questions & Answers

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
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
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
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
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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Source:  OpenStax, Technology grade 8. OpenStax CNX. Sep 13, 2009 Download for free at http://cnx.org/content/col11052/1.1
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