Technology in Action (p.367-373)

Technical Objects An object conceived and manufactured by humans to meet one or more needs or wants Materials- used to make parts of a technical object -Materials ex. Wood planks - Equipment ex. Saws, hammers, etc.

Raw Materials Natural substance, must be transformed: trees

Material Substance that has been transformed: Ex. Wood planks

Equipment Instruments used to produce an object Ex. Saw etc.

Mechanical Constraints Describes the stress produced within the material when it is subjected to external forces

Compression Compression: force that crushes materials

Tension Tension: Force that stretches materials

Torsion Torsion: Force that twists materials

Bending Bending: Force that bends materials

Shearing Shearing: Force that cuts or tears materials

Resist Mechanical Constraints Materials- resist constraints before being deformed 3 Types Elastic (material regains its shape), Plastic (remains deformed) , Fracture (material ruptures)

Mechanical Properties Determines how a material will react when it is subjected to one or more mechanical contraints

Hardness Ability to resist penetration when force is applied (elastic deformation) Ex. Marble is hard

Tensile strength Ability to resist tension without becoming permanently deformed (elastic deformation)

Resilience Ability to resist impact (elastic deformation)

Malleability Ability to be flattened or bent without breaking (reacts to bending or compression by plastic deformation)

Ductility Ability to stretch without breaking (tension force by plastic deformation) Ex. Copper can be drawn into a wire

Elasticity Ability of an object to return to its original shape when the force acting on it is removed

Electrical Conductivity * Ability to conduct an electrical current

Thermal Conductivity* Ability to conduct or transfer heat

Coefficient of Thermal Expansion* Property characterizing the relative increase in the volume of a body according to the increase in temperature

Corrosion resistance* Ability to resist the action of smoke, salt, and chemical products that cause corrosion(rust)

Basic Mechanical Functions Parts or fluids that have a mechanical function Basic Mechanical - role of a component or group of components in the function or assembly of an object.

Guiding Basic mechanical function of any component that controls the motion of one or more moving parts.

Guiding Allows rotation Ex . Hole punch Translation motion Rotatinal Translational Allows rotation Ex . Hole punch Translation motion Ex. Groove in handle

Thermometer

What would be the components. What would be guiding What would be the components? What would be guiding? What type of motion does a thermometer have?

Make a Thermometer What do you need? Tap water Rubbing alcohol (do not drink this) Clear, flask Food coloring Glass Tube Rubber stopper

What to do? Pour equal parts of tap water and rubbing alcohol into the flask, filling about 1/8 to a 1/4 of the bottle. Add a couple of drops of food coloring and mix. Put the straw in the flask, but don't let the tube touch the bottom (DO NOT DRINK THE MIXTURE). Use the rubber stopper to seal the neck of the flask, so the glass tubing stays in place. We will then turn the flask into a thermomter.