Pitlochry Primary School Online Programme Dear Grade 7

Pitlochry Primary School Online Programme

Dear Grade 7 Learners. I hope that you are all well and keeping those hands clean! I miss you all so much! Below I have given you some revision and summary based on Term 2 work. Please go over all the notes thoroughly. Please ensure that you complete them on exam pad pages which will go into your file when we return to school. All tasks will be checked and marked. Remember to work hard and use this time to be productive. Make some time for your schoolwork every day and some time for fun. Have a schedule. Balance is important. Keep in touch with your friends. Make sure that they are doing their work too and help each other where you can. It is during times like these where we have to support each other the most. You are in my thoughts and prayers. Take Care! Miss Mark Click Me!

Lesson 8 Topic: Revision Grade: 7 Presented By: Miss Mark Pitlochry Primary School Educator

STRUCTURES • Structures contain, protect, support and/or span something. Anything which serves one or more of these purposes is considered a structure. • Structures are either manufactured or they are natural.

TYPES OF STRUCTURES • There are THREE types of structures : SHELL STRUCTURES, FRAME STRUCTURES, SOLID STRUCTURES. Curved Can take a lot of pressure and stress SHELL STRUCTURES Can span large areas without needing internal support Strong

Supported by a skeleton rather than load-bearing walls FRAME STRUCTURES Frame structures without a skin are called open frame structures Some frame structures have a skin over them

Solid structures are also called MASS STRUCTURES SOLID STRUCTURES Each part supports the next part up These structures are a result of piling bits of solid material on top of each other

INVESTIGATING STRUCTURES • Cell phone towers are structures built to facilitate cellular phone and other wireless communication in a cellular network. • Although frame structures appear to be less sturdy than shell or solid structures, they are very strong and can remain standing for years. • They are made up of many metal pieces welded together. • There are many different designs of cell phone towers.

TRIANGULATION • One of the methods used to strengthen frame structures is TRIANGUALTION. • The triangle is a very strong structural shape. • When a force or pressure is exerted on a triangle, two of the sides stretch the third side. This side then pulls the other two sides towards itself. • All this stretching and pulling means TWO things: 1. The structure stays rigid 2. The force is spread among all three sides of the triangle. This spreading of the force makes the shape very stable.

ACTIVITY 1. What is the purpose of structures? 2. Define each purpose. 3. Name a natural and a man-made structure that performs each purpose. 4. What are the THREE types of structures that we have learnt about? 5. State one defining characteristic of each type of structure. 6. What are cell towers? 7. What type of structure are cell towers? 8. What type of design issues do cell towers have? State TWO.

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