Presentation on theme: "Technology Work book / Text book. Term # 3 Materials – Constraints Lab Mechanical Function – Links Lab Complex Mechanical Function – Gears Lab Noise Maker."— Presentation transcript:
Technology Work book / Text book
Term # 3 Materials – Constraints Lab Mechanical Function – Links Lab Complex Mechanical Function – Gears Lab Noise Maker
Text / Work Books Text Book - p. 368 Work Book - p. 195 Copy the following definitions
RAW MATERIAL – p. 195 A natural substance that must be transformed before being used to manufacture an object.
MATERIALS A substance that has been completed or transformed by humans and is then used to make an object or its parts.
EQUIPMENT Includes all instruments used to produce an object.
A TECHNICAL OBJECT Is an object conceived and manufactured by humans to meet one or more needs or wants (p. 368)
A MECHANICAL CONSTRAINT… Describes the stress produced within a material when it is subjected to external forces. (p. 369)
A MECHANICAL PROPERTY… Determines how a material will react when it is subjected to one or more mechanical constraints.
Compression – p.370 Force that crushes materials
Tension Force that stretches materials
Torsion Force that twists materials
Example of Torsion
Bending Force that bends materials.
Examples of Bending
Shearing Force that cuts or tears materials.
Example of Shearing
Elastic - p. 371 This results in a temporary deformation of the material. When the constraint is removed, the material regains its shape.
Plastic Even when the constraint is removed The material remains deformed
Fracture The material ruptures after being subjected to the constraint.
Activity # 1 Compression / Torsion / Deflection Get a partner Get a handout Get one box per table
Goal Observe the effects of various constraints on different types of materials
Materials Strip of Iron Strip of Polypropylene 3 Strips of Wood Bar Clamp Universal Clamp Retort Stand Ruler 1000-g weight with hook
Procedure Part A: Compression – Place the strip of iron between the jaws of the bar clamp and tighten the jaws – Loosen the jaws of the bar clamp and remove the strip of iron – Record the type of deformation you observe – Repeat steps 1 to 3 with the strip of polypropylene and wood