INTRODUCTION. We take bridges for granted in our daily lives. We regularly cross bridges of various types and lengths without even thinking about it.

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2 INTRODUCTION We take bridges for granted in our daily lives. We regularly cross bridges of various types and lengths without even thinking about it. But imagine how much harder travel would have been for the early explorers and settlers of Australia without bridges, particularly when they needed to cross larger streams and rivers.

3 When explorers Hume and Hovell travelled through New South Wales and Victoria towards South Australia in 1824, they improvised bridges with tarpaulins wrapped first around a cart, and later around a structure made of poles, in order to ferry their party and its supplies across the Murrumbidgee and Murray Rivers. They were severely hampered by the lack of bridges.

4 The early history of bridges is not recorded, but it is likely they would have been fallen trees across streams, which people walked over.

5 Later, simple rope or vine bridges would have allowed people to climb across, and from this would have come more complex rope bridges made up of many ropes fixed together, eventually with decking which made it easier for people to walk across. However rope bridges are not long-lasting, and not suitable for heavier vehicular traffic.

6 The next technological development in bridge design was the stone arch bridge. These date from Roman times, around two thousand years ago. For their structural strength they depend on the shape of the arch. In a simple arch bridge, the weight of the bridge and the load crossing it is transmitted through the arch to the walls (the banks of the stream or river), so the arch does not collapse.

7 In order to cross a wider span, numerous arches could be linked together, with the ends of each arch supported by a post or pillar. Many very large and long bridges and viaducts were constructed in this way in Roman times, with some surviving even to this day.

8 Stone arch bridges continued to be built for many centuries. There are some classic examples of these still surviving from early Australian convict times, particularly in Tasmania. However, the emergence of structural steel as a building material during the industrial age allowed the design and construction of bridges on a scale never before contemplated.

9 The early citizens of Sydney and San Francisco could never have imagined their harbours would be spanned by huge steel bridges. Even some eighty years after its construction, the Sydney Harbour Bridge remains a great Australian icon and engineering achievement.

10 There are numerous variations in the design of such large bridges, including cable suspension bridges, steel arch bridges, cantilever bridges, and truss bridges.

11 ACTIVITY Build a Straw Bridge Students will: work as part of a team, each playing a particular role; design, make, test and critique a straw bridge; gain hands-on experience in design and construction; discover how to best record all observations, planned modifications and observed results in a journal; and build on their speaking and listening skills by sharing their straw bridges.

12 PROJECT The project is for a team of four students to design and construct a model of a single-span bridge, using plastic drinking straws as the building material. DESIGN The bridge needs to span a distance of 20 cm and be approximately 10 cm wide. There should be no supporting pillars to the ground in between the ends of the span. It must be strong enough to support a suitable load placed on the middle of the completed structure. Sketch your ideas

13 CONSTRUCTION You will need: Plastic drinking straws (20 per bridge as a rough guide). 1 m of masking tape. Scissors to cut the straws to appropriate lengths. A load to test the bridge with (this will be done under teacher supervision at the test station). TEST STATION

14 CONSTRUCTION COSTS The designs of structures such as bridges should be as cost effective as possible. To comparing the costs of the different designs, students are to calculate the cost of their structure using the formula below: For each straw used $1000 For each 1 cm of tape $2000 For each cut or bend in a straw $1000 Total $

15 TESTING Set the bridges up across the gorge and gently place the load on the structure to see if the design will support the weight.

16 Create a Catapult

17 Check out The Catapult History

18 YOUR MISSION Design a catapult to launch a marshmallow the furthest distance possible

19 YOU WILL NEED: 10 paddle-pop sticks 1 elastic band 1 plastic spoon 2 metres of tape

20 Wind- Powered Sail Car STEM Challenge

21 Natural Energy Challenge Design a car that doesn't need gas to make it go but uses a pollution-free energy source instead

22 Learning Objectives You will learn to: Build a small-scale wind-powered sail car using experimentation and designing techniques Work collaboratively to create a winning design (sail car)

23 Video of wind powered sail cars

24 STEM Challenge In your team, design and construct a small, wind-powered sail car which can travel the furthest with the wind. Compete with other teams to see which sail car travels the farthest

25 Competition Rules Work collaboratively in teams of four The sail car should not exceed 100g use scales to measure weight Use only the materials provided

26 Winning Criteria The winner is the car that travels the furthest from the start line before it either stops or goes off course Do three trials and average your results If there is a tie the lightest car will win

27 Competition Organisation

28 What you can use... Plastic straw wheels Writing paper, tissue paper, aluminium foil, plastic Sticky tape Scissors Electric fan Weighing Scale Plastic cup Bamboo skewer

29 So how are we going to work on this challenge -Easy! Work in your group and follow the design process in your booklet Complete the questions and brainstorm 15 mins (Part B) Create your model and test it 20 min (Part C) Challenge time 20 min (Part D)

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