1. Unit D: Structures & Force Topic 1.1 – Classifying Structures  Key Terms  Structure  Force  Stability  Strength  Types of Structures  Solid  Frame  Shell

2. Need to Know Terms  Structure  Any object that provides support  Can be made of one or many parts, may be large or small  A chair, a tree, a statue, a car, a rock, a bone….  Force  A push or pull that can cause and object to change its movement or shape  Structural Strength  The ability of a structure to support both its own weight plus any additional weight applied to it  Structural Stability  The ability of a structure to maintain its position even when it is being acted on by forces  To keep balanced and not get knocked over

3. The Three Types of Structures 1. Solid Structure  A structure made of a solid piece, or a solid combination of pieces, of strong material 2. Shell Structure  A structure with a solid outer surface and a hollow inner area 3. Frame Structure  A structure consisting of a rigid (firm) arrangement of parts joined together

4. Solid structures have little or no space inside and are usually the strongest of the three types

5. The strength of frame structures comes from the way its parts are assembled

6. Shell structures are stronger than frame structures and lighter than solid structures, which is why they are used for protection