PLTW IED Sem 2 Voacb

Variation

The difference between two similar objects or from a standard

Tolerance

The total allowed amount a dimension can vary

Unilateral Tolerance

Variance is allowed in only one direction (e.g., +0.05/-0.00).

Bilateral Tolerance

Variance is allowed in both directions (e.g., ±0.05)

Limit Dimensions

Showing the maximum and minimum allowable sizes directly (e.g., 1.05/0.95)

Interchangeable Parts

Mass-produced parts made to fit into any assembly of the same type

Mean

The mathematical average of a data set

Median

The middle number in a sorted list of data

Clearance Fit

A fit where there is always a gap between parts

Interference Fit

A tight fit where parts must be forced together

Transition Fit

A fit that might be loose or tight depending on the tolerance

Selective Assembly

Matching specific parts together to get the best fit

Allowance

The tightest possible fit between two mating parts

Adhesives

Chemical substances like glue or epoxy used to bond materials

Fasteners

Hardware like screws, and bolts that mechanically join parts

Joinery

Methods used to connect pieces of wood together

Snap-fit joints

Flexible parts that deflect and click into place to connect

Threads

Helical ridges on screws or bolts used to fasten objects

Reverse Engineering

Taking an object apart to see how it works

Visual Analysis

Examining a product based on its looks and aesthetic features

Line

A path created by a moving point

Shape

A two-dimensional closed area

Form

A three-dimensional volume or object

Color

Light reflected off objects (has hue, value, and intensity)

Texture

Look or feel of a surface

Space

Area around, between, or within components

Value

Relative lightness or darkness of a color

Hue

The name of the color itself (e.g., red, blue)

Saturation

The intensity or purity of the color

Value

How light or dark the color is.

Balance

Equal distribution of visual weight (symmetrical, etc.)

Emphasis

Drawing attention to a specific focal point

Contrast

Noticeable differences between elements to create interest

Rhythm

Repeating elements to create a sense of movement

Proportion

Size relationship between parts of a whole

Unity

Elements working together to look complete

Economy

Keeping a design simple and efficient

Functional Analysis

Studying what a product does before knowing how it works

Inputs

Resources put into a system

Outputs

Results produced by the system

Black Box Hypothesis

Diagramming inputs and outputs without knowing the inner mechanics

Structural Analysis

Figuring out how a structure handles loads and forces

Systems Thinking

Looking at how different parts interact within a whole system

Stress

The internal force inside a material

Strain

How much it stretches or deforms because of that force

Fatigue Resistance

A material’s ability to withstand repeated, repeating loads without breaking

Impact Resistance

Ability to withstand a sudden, high-force blow without shattering

Creep

Slow, permanent deformation that happens when a material is under constant stress over a long time

Wear and abrasion resistance

Ability to resist surface damage from rubbing or scratching

Environmental Performance

How well a material holds up against weather, chemicals, or UV light

Thermal expansion and contraction

Materials growing larger when heated and shrinking smaller when cooled

Fatigue

The progressive weakening over time

Failure

The actual breaking or yielding point

Metal

Strong, shiny materials that conduct heat and electricity well (e.g., steel, aluminum)

Ceramic

Hard, brittle, heat-resistant materials made by baking clay or minerals

Polymer

Light, flexible materials made of long molecular chains (plastics, rubber)

Composites

Materials made by combining two or more distinct substances to get better properties

Biomaterials

Materials engineered to safely interact with biological systems

Alloys

A mixture of two or more metals, or a metal mixed with other elements

Yield Strength

The point where a material permanently deforms and won’t snap back

Ultimate Strength

The maximum amount of stress a material can handle before completely breaking

Young’s Modulus

A measure of a material’s stiffness (how easily it stretches or compresses)

Density

How tightly packed the matter inside a material is (mass/volume)

Tensile Strength

A material’s resistance to breaking under a pulling or stretching force

Melting Point

The temperature at which a solid turns into a liquid

Electrical Resistivity

How strongly a material opposes the flow of electrical currect

Specific Heat

The amount of heat needed to raise the temperature of material by one degree

Coefficient of thermal expansion

A number showing exactly how much a material expands or contracts per degree of temperature change

Ductility

A material’s ability to be stretched out into a thin wire without snapping

Malleability

A material’s ability to be hammered, rolled, or pressed flat into sheets without cracking

Stiffness

A material’s ability to resist bending or stretching when a force is applied

Toughness

Material’s ability to absorb energy before breaking

Hardness

Material’s resistance to permanent deformation, indentation, and scratching

Brittleness

Tendency to break when stressed with little deformation before fracturing

Plasticity

Ability of a material to undergo irreversible deformation; opposite of brittleness

Sustainability

The practice of designing products, systems, and infrastructure that meet current human needs without compromising the ability of future generations to meet theirs

Biomimicry

Copying designs, structures, and strategies from nature to solve human design problems

Cradle to Cradle

A design approach where products are recycled completely into new products at the end of their life, creating zero waste

Design for Disassembly

Designing a product so it can be easily taken apart at the end of its life for recycling or repair

Green Chemistry

Designing chemical products and processes that reduce or eliminate the use of hazardous substances

Green Marketing

Promoting products or services based on their environmental benefits

Product Stewardship

The idea that everyone involved in a product’s life cycle is responsible for reducing its environmental impact

Human-centered design

An approach to problem-solving that puts the actual needs and behaviors of people at the center of the entire design process.

Inspiration

The initial phase of gathering information, researching user needs, and deeply understanding the problem

Ideation

The creative phase of brainstorming, developing, and testing a wide variety of potential solutions

Implementation

The final phase of turning the best idea into a real, functional product and bringing it to life

Linear Motion

Object moves in a straight line

Rotary Motion

Rotation around a fixed axis that is interior to the object

Circular Motion

Rotation around a fixed axis that is exterior to the object

Reciprocating Motion

Back-and-forth movement in a straight line

Oscillating Motion

Back-and-forth movement along a curved path or arc

Pear Cam

Shaped like a pear

Heart Cam

Shaped like a heart

Eccentric Cam

A perfect circle with an off-center point

Snail Cam

Shaped like a snail shell