Humans build structures to meet specific needs. In Grade 7, you will learn about the effects of forces that act on and within different structural forms. You will learn about designing, building and testing structures, using increasingly sophisticated techniques.
A structure is defined as building or other object constructed from several parts.
Source: Oxford Dictionaries, http://www.oxforddictionaries.com/definition/english/structure
A bridge is defined as a structure carrying a road, path, railway, etc., across a river, road, or other obstacle.
Source: Oxford Dictionaries, http://www.oxforddictionaries.com/definition/english/bridge
Levers are used to lift heavy weights with the least amount of effort .