Towers

Principle: Lowering the Center of gravity of the structure to make it more stable is a critical thing and a strong foundation plays a important role in the stability and life of a tower.

Things to Learn:
Center of gravity of different shapes
Properties of angles, triangles, quadrilaterals, triangular prisms, cuboids, etc.
Items Required to make:
Straws & pins OR
Paper & Glue OR
Popsicle Sticks (ice cream sticks) and glue

Fun Facts to know:
CN Tower, Toronto, Canada: Total Height of Tower 553.33 metres (1,815 ft. 5 in.)
Architects John Andrews, Webb Zerafa, Menkes Housden, E.R. Baldwin
Concrete quantity used for construction (m³): 40,524m³
5,000 tons of reinforcing steel used for construction

Hovercraft

Principle:The air is forced downwards towards the bottom of the craft and this creates a cushion of air lifting the whole machine upwards. The air pushed backwards propels the hovercraft into forward direction and this helps maneuvering it.

Applications:
Steam engines use the same principle, thought the steam there is used to propel the blades of a turbine.

Items Required to make:
Boat shape material (could be plastic soap box or it can be made using an old tin can) with a hole at the back end bottom
Balloon

Fun Facts to know:They are amphibian, can travel both on land and in water

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