Presentation on theme: "The Wonderful World of… TECHNOLOGY. IN YOUR OPINION: What IS technology?"— Presentation transcript:
The Wonderful World of… TECHNOLOGY
IN YOUR OPINION: What IS technology?
What is Technology? Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. (Wikipedia definition)
Whats a Technical Object? A man-made object that serves a purpose.
Your Pencils Is it a technical object? Take a look at your pencils in your hands. What are the materials it is made of? How are materials decided for certain technical objects?
MATERIALS External forces produce various effects inside a material. EXAMPLE: *Consider what would happen if an elephant walked in the room and stepped on your pencil. What would the effect be? EXTERNAL FORCE = Elephant weight EFFECT = pencil being crushed
Different materials react differently to different external forces.
MECHANICAL CONSTRAINTS A mechanical constraint describes the stress produced within a material when it is subjected to external forces. 5 types of constraints: Compression, Tension, Torsion, Bending, Shearing
COMPRESSION: Force that crushes materials
TENSION: Force that stretches materials
TORSION: Force that twists materials
BENDING: Force that bends materials
SHEARING: Force that cuts or tears materials
EXAMPLES: SHOES: CLICKER: WATER BOTTLE:
What happens when there is TOO MUCH STRESS (constraint) on material? Elastic deformation – Temporary deformation of material. Resumes shape. Plastic deformation – Remains deformed. Fracture – Material ruptures.
Your Pencils (again) Have you ever asked yourself why pencils are never made out of rubber? Or out of glass?
MECHANICAL PROPERTIES Determines how a material will react when it is subjected to one (or more) mechanical constraints. Examples of properties: Hardness, elasticity, ductility, malleability, tensile strength
Resists penetration Reacts to pressure force by elastic deformation
Regains initial shape Reacts to force by elastic deformation
Resists physical impacts Reacts to temporary force by elastic deformation.
http://www.youtube.com/watch?v =j87UWgvetRg Building Design Pulls Structure Upright after Earthquake
Stretches without breaking Reacts to tension force by plastic deformation.
Flattens or bends without breaking Reacts to bending or compression force by plastic deformation.
Resists tension without becoming permanently deformed Reacts to tension force by elastic deformation