6.1 What gives a product structural integrity?

a. How and why specific materials and/or system components need to be reinforced or stiffened to withstand forces and stresses.

1. Material Selection:

   • Metals: Strong and ductile, often used in construction (e.g., steel beams) and automotive industries.

   • Composites: Materials like carbon fiber are used in aerospace and high-performance sports equipment due to their high strength-to-weight ratio.

   • Wood: When choosing wood for structural purposes, hardwoods like oak are preferred for their durability and strength.

2. System Components:

   • Joints and Connections: Bolted or welded joints in steel structures, dovetail joints in woodwork, and snap-fit joints in plastic products provide necessary reinforcement.

   • Frames and Supports: Internal frames in products like bicycles and furniture (e.g., IKEA’s flat-pack furniture) ensure stability and load distribution.

3. Reinforcement Techniques:

   • Stiffening: Adding ribs or gussets to plastic components (e.g., the inside of a plastic chair) increases rigidity.

   • Laminating: Plywood, made by gluing multiple layers of wood at different angles, is stronger and more stable than single-layer wood.

b. Awareness of the processes that can be used to ensure the structural integrity of a product, such as:

1. Triangulation:

   • Usage: Common in trusses and frameworks (e.g., bridges, roof supports). Triangular shapes distribute weight and resist deformation.

   • Example: The Eiffel Tower uses triangulated structures extensively to maintain stability and strength.

2. Use of Boning, Darts, and Layering in Textile Products:

   • Boning: Used in corsetry and garment construction to provide shape and support (e.g., in wedding dresses).

   • Darts: Tapered seams in clothing that provide a better fit by shaping the fabric around body curves.

   • Layering: In garments, layering fabrics (e.g., lining a coat) adds durability and comfort.

3. Plastic Webbing:

   • Usage: Strengthens products without adding significant weight (e.g., in lawn chairs, sports equipment).

   • Example: The use of webbing in camping chairs to distribute weight evenly and prevent sagging.

4. Reinforcing:

   • Concrete Reinforcement: Adding steel bars (rebar) to concrete structures enhances tensile strength (e.g., in buildings, bridges).

   • Fiberglass Reinforcement: Used in boat hulls and car bodies to increase strength without adding much weight.

6.2 How can materials and products be finished for different purposes?

a. The processes used for finishing and adding surface treatments to materials and products for specific purposes, including:

1. Function (Durability and Added Resistance to Overcome Environmental Factors):

   • Painting and Coating: Protects materials from corrosion, UV damage, and wear (e.g., automotive paint, anti-rust coatings on steel).

   • Galvanizing: Applying a zinc coating to steel or iron to prevent rusting, commonly used in outdoor structures like fences.

   • Anodizing: An electrochemical process that increases the thickness of the natural oxide layer on aluminum parts, enhancing corrosion resistance and appearance.

2. Aesthetics:

   • Polishing: Improves the surface finish of metals, plastics, and wood, giving a glossy and attractive appearance (e.g., polished granite countertops, polished metal parts in watches).

   • Varnishing: Applying a protective and decorative finish to wood, enhancing the grain and providing a glossy or matte finish (e.g., in furniture, flooring).

   • Electroplating: Coating a metal object with a thin layer of another metal (e.g., chrome-plated car parts, gold-plated jewelry) for improved appearance and resistance to tarnishing.

6.3 How do we introduce controlled movement to products and systems?

a. An overview of different sorts of movement and types of motion, including:

1. Rotary:

   • Description: Circular movement around a central point or axis.

   • Example: The wheels of a car rotate around the axle, and a drill bit rotates to create holes in materials.

2. Linear:

   • Description: Movement in a straight line.

   • Example: A piston in an engine moves linearly within a cylinder, and the cutting blade of a guillotine moves downwards to cut paper.

3. Oscillating:

   • Description: Back-and-forth movement in an arc.

   • Example: A pendulum in a clock oscillates to keep time, and the movement of a child’s swing is oscillatory.

4. Reciprocating:

   • Description: Back-and-forth movement in a straight line.

   • Example: The needle in a sewing machine moves up and down in a reciprocating motion, and the motion of a saw blade in a jigsaw is reciprocating.

b. The effect of forces on the ease of movement, including:

1. Load:

   • Description: The weight or resistance that is being moved or lifted.

   • Example: In a lever system, the load is the object being lifted, such as a rock in a seesaw arrangement.

2. Effort:

   • Description: The force applied to move the load.

   • Example: Pushing down on one end of a seesaw to lift a rock on the other end is the effort applied.

3. Fulcrum:

   • Description: The pivot point around which a lever turns.

   • Example: The central support of a seesaw is the fulcrum, around which the seesaw pivots.

c. How different mechanical devices are used to change the magnitude and direction of motion or forces, including consideration of:

1. Cams:

   • Description: Rotating or sliding pieces in mechanical linkages used to convert rotary motion to linear motion.

   • Example: The camshaft in an internal combustion engine uses cams to open and close the engine valves.

2. Gears:

   • Description: Toothed wheels that transfer motion and force from one part of a machine to another.

   • Example: Bicycle gears change the speed and torque of the wheels depending on the gear selected.

3. Pulleys and Belts:

   • Description: Systems using wheels and belts to transfer force and motion.

   • Example: Pulleys are used in elevators to lift the cabin, and belts are used in car engines to drive various components.

4. Levers and Linkages:

   • Description: Rigid bars and connected parts that transfer force and motion.

   • Example: Scissors use a lever mechanism to cut materials, and linkages are used in folding mechanisms such as in folding chairs.

6.4 How do electronic systems provide functionality to products and processes?

a. How sensors and control devices respond to a variety of inputs, including:

1. Sensors:

   • Light Dependent Resistors (LDR): Changes resistance based on light intensity, used in automatic lighting systems.

   • Infra-red Sensors: Detects infrared light from objects, used in motion detectors and remote controls.

2. Switches:

   • Tilt Switches: Detects orientation or angle, used in devices to detect tilt or rollover.

   • Push-to-Make Switches: Completes the circuit when pressed, used in doorbells and keyboards.

   • Time-delay Switches: Activates a circuit after a set period, used in bathroom fan systems that stay on for a short period after the light is turned off.

b. How devices are used to produce a range of outputs, including:

1. Light-emitting Diodes (LED):

   • Description: Semiconductor devices that emit light when an electric current passes through them.

   • Example: LEDs are used in display screens, indicator lights, and energy-efficient lighting.

2. Speakers and Buzzers:

   • Description: Convert electrical signals into sound.

   • Example: Speakers are used in audio systems, and buzzers are used in alarm systems and electronic toys.

3. Motors:

   • Description: Convert electrical energy into mechanical motion.

   • Example: Electric motors are used in household appliances like washing machines, fans, and electric cars.

c. The use of programmable components such as microcontrollers, to embed functionality into products in order to enhance and customize their operation.

1. Microcontrollers:

   • Description: Small computing devices that can be programmed to perform specific tasks and control electronic systems.

   • Example: Arduino microcontrollers are used in DIY electronics projects to control LEDs, motors, sensors, and other components.