Technology Terminology Structure a structure is something that

Technology � Terminology � Structure- a structure is something that has been built, put together in a particular way to support a load. � Shell structure- a hollow structure that is used to contain or protect something. � Frame structure- a framework of parts that are joined together to support a load. � Solid structure- a structure that is solid or rigid in nature made of materials that do not have joints. � Strut- a rod that can be diagonal in nature that supports other parts to keep them from collapsing. � Tension force-a force that pulls apart or stretches a member � Compression force- a force that pushes objects towards one another to create a colliding force. � Triangulation- arranging members in a triangular shape. � Pylons- are made from strong materials that support heavy objects in powerlines in a frame structure. � Tie beams are horizontal frames that enable the tower to hold other crosspieces together.

Frame structures � They consist of different parts that can be joined together to make them strong. � Examples of frame structures include bridges, bicycles, ladder, burglar door etc. � Classify the following into man- made and natural frame structures.

Shell structures � Shell structures contain and protect their contents examples include, egg shells, cups, bottles, fridges etc. � Classify the following into man-made and natural structures.

Solid structures � Solid structure- a structure that is solid or rigid in nature made of materials that do not have joints. Examples include a wall, log, mountain etc. � Classify the following into man-made and natural structures.

Classify the following correctly Frame structures Shell structures Solid structures Roof tiles Rocks Coffee mugs Brick Spider web Electricity pylon Dog kennel Foundation for buildings Bridges Bath tubs Cutlery Bowls Human skull Bowls Chicken eggs Cellphone tower Tables Vases Wooden logs Burglar door Ladder Chairs Iron beams Steel railway line Concrete pillars Dustbin Gold bars Cups Bicycle Garden chairs House Bike helmets Basins

Purposes of structures �Structures play a vital role in our society. Their main purposes are to; �Contain �Protect �Support �Span – space between two objects so that they are connected.

Triangulation �Triangulation refers to the arrangement of frames to form triangular shapes that allow stability and strengthen the objects. �Activity �Read pg 62 -63 platinum book and complete task 4 on pg 63. �List at least 5 other structures around your community where triangulation frames have been used i. e. roof trusses, windmill etc. �Make a triangular and a square strut using papers or cardboard strips, test why the triangular frame is essential in strengthening cell phone towers. You can use split pins to join the struts.

Triangulation � After making the square and triangular struts compress them to ascertain the strongest one. � To strengthen the square strut, you can add another strut to form triangular struts.

Cell phone Towers � A cellphone tower is an example of a frame structure. � Cellphone towers consists of beams and struts that enable the tower to be stable to withstand compression and tension forces. � Cellphone towers consist of devices that are called receivers and transmitters. Theses allow communication or messages to be received and transmitted easily. � The struts strengthen the cell phone tower frames. � The best strut to strengthen the tower is s triangular strut. � The wide bases allow the tower to be strong. � Triangulation of the beams enable the tower frames to be stronger. Activity: Read pg 60 -61 and work on task 3 pg 61, Platinum book.

Telephone systems � Pylons are used to carry landline cables across long distances. Pylons are tall frame structures that can hold heavy cables or power lines to allow communication to be enhanced across long distances. � Telephone towers are made of materials that are strong and durable enough to handle the heavy weight of the cables. � Tie beams are used in telephone towers to hold other members and prevent spreading or separation of parts. �

Phone towers �Activity �Read on pg 64 platinum book and work on task 5 pg 65. �Identify other advantages and disadvantages of cellphone towers in your community. Draw a table and list these. �Draw a 3 D telephone tower and reflect triangulation. �Use a single vanishing point perspective drawing and oblique drawing �Compare the advantages and disadvantages of using cellphones and landlines. Which one would you prefer.

Strengthening structures Tubing can be used to strengthen materials and structures. � In tubing, the materials used are essential in ensuring the stiffening of the structures. � Stiffening refers to making something rigid or strong. � Tubing can either be circular, rectangular, triangular or square shaped in nature. � Folding is another way of strengthening structures. � Triangulations is another form of strengthening structures. � Activity � Individually investigate the best way of stiffening materials on page 66 -67 platinum book and test them. � You can use books to test and observe the best way of stiffening structures. � Write your responses to question 4 pg 67 based on the observed results in your book. � Write the conclusion on question 5 as well. �

Ways of strengthening materials

Environmental effects � Cellphone towers have an effect among human lives and the environment. � They can cause pollutions light pollution, visual pollutions etc. � Activity � Read on pg 68 -71 and answer the question on task 1 pg 71. � Define visual pollution, stability, base size and center of gravity. � Why is it important to consider the following design issues like visual pollution, stability, base size and centre of gravity in designing structures? � Identify the impact cellphone towers have among humans. � Identify the effect cellphone towers have on the environment in South Africa.

Structural elements � The structural elements are essential in reinforcing the structure. � Which materials are strong enough in the construction of cellphone towers to ensure that the cellphone tower is strong enough to last a long time? Give a reason for your answer. � Copy and complete the table below; Element Strut Column Tie beams Guy Foundation Function

Case study �Read the case study on the cellphone towers designs on pg 72 and compare them. �Read another case study on existing desks and write answers on the design brief, design specifications and task 2 pg 75. �Identify one technological gadget in your immediate environment and note the changes that have resulted in the advanced evolution of the product i. e. televisions, couches, radios, fridges etc.

Cellphone designs � Cellphones have evolved over time. � Compare the features of cellphones on the pictures. � Read on pg 76 and answer questions on pg 77.

Informal assessment �The mini-Pat is an informal assessment. �Work on the Mini-Pat on pgs 78 -87.

Revision 1. What is a structure? 2. Identify the three properties that all structures have in common. 3. Decide whether the following are TRUE or FALSE; a) A skeleton of a fish is a man-made structure. b) The chair I sit on is a man-made structure. c) The mountains are natural structures. d) The bee hive is a man-made structure. 4. Define the term strut. 5. Which strut is more stable or rigid?

Revision cont. � List four functions of structures. � Name three types of structures and identify their differences. � What effect does the compressional force have on a structure? � What is the effect of tension forces on a structure? � Explain the following terms; tie beams, column, guy. � Explain how triangulation strengthens a structure. � Which type of pillar is effective in strengthening structures? � How do these design aspects contribute in the construction of cellphone towers? � What is the purpose of a cellphone tower? � List the advantages and disadvantages of using an electrically charged cellphone to a solar charged cellphones.