NVHS PLTW Intro to engineering design

PLTW

Mean

the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores (average)

Median

the middle score in a distribution; half the scores are above it and half are below it (middle number)

Mode

the most frequently occurring score(s) in a distribution

interquartile range

The difference between the upper and lower quartiles.

concept sketch

A quick and informal way of communicating and labeling a designers idea through 2D application.

annotation

Notes added to a work to explain or add information

Accuracy

How close the spread of something is relative to a target or value

Precision

a measure of how close a series of measurements are to one another

Accuracy error

Refers to how close the instrument is reading to the "true" value being measured.

Engineering notebook

A book that records the engineering and design process, used to record thoughts and and store technical info

PLTW Design Process

1. Define Problem
2. Generate Concepts
3. Develop a Solution
4. Construct and Test Prototype
5. Evaluate Solution
6. Present Solution

Criteria

A means of judging something based on certain qualifications

Constraints

A limit to the design process, such as funding

Decision matrix

A tool for systematically ranking alternatives or designs according to a set of criteria.

Isometric

a 3d sketch of an object. Object faces are distorted.
(30 degrees between space on bottom and sides, pictorial drawing)

Dimensions of a 3d object

Depth
Width (Length)
Height

Names of faces of an isometric drawing

Front
Right
Top

Additive

adding shapes to an existing object to model an object

Subtractive

starting with a object and cutting segments out

Orthographic projection

Represents 3d objects on a 2d plane as 2d faces, shows size more accurately than Isometric

construction lines

Thin, light lines that serve as guides while sketching or drawing.

object lines

A heavy solid line used on a drawing to represent the outline of an object.

hidden line

A line type that represents an edge that is not directly visible. Appears as dashed lines

centerline

A line type that is used to indicate the axis of symmetry for a part or feature. Appears as a hyphen or dash surrounded by 2 lines

center mark

A cross that marks the center of a circle or arc.

Dimension lines

A line which represents distance.

extension lines

Thin lines used to establish the extent of a dimension.

Leader line

Line which indicates dimensions of arcs, circles and detail. Do not cross these lines

Datum Dimensioning

A dimensioning system where each dimension originates from a common surface, plane, or axis. Also known as baseline dimensioning.

Chain Dimensioning

Also known as point-to-point dimensioning where dimensions are established from one point to the next.

Chain Dimensioning

Also known as point-to-point dimensioning where dimensions are established from one point to the next.

Circles/Arc measurement

Circles measured using diameter, Arcs measured radius