Science Unit 3 Test

Structure

An object with a definite shape and size which serves a definite function

Force

a push or a pull

2 structure types

Natural, manufactured

Natural structures

Structures not built by humans

Manufactured structures

Structures built by humans

4 ways structures can fail

Shear, Bend/Buckle, Torsion, Metal Fatigue

Shear

When one section of a structure slides over another along its weakness

Bend/buckle

When compressive forces are exerted on a structure and causes the material to bend on the inside of the curve and pull/snap on the outside of the curve until it gives way

Torsion

Application of twisting forces to a structure

Metal fatigue

Metal weakening after experiencing bending or twisting forces over a period of time

Shearing

What does torsion cause?

3 things to think about when designing with forces

Distribute the load, direct forces using angles, shape the materials

Distributing load

Ensuring no part of the structure carries most of the load

Directing forces using angles

Direct forces along angled components so forces hold pieces together instead of pulling them apart

Shaping materials

Shape the materials to withstand a specific type of force

Examples of distributing the load

triangles

Examples of directing forces using angles

arches, keystones

Examples of shaping materials

“I-beam”, “T-beam”, corrugated cardboard

Cantilever

Horizontal board/span supported by a very strong column at one end

Braces

Used to direct the forces through the solid part of the structure to the ground

Buttress

Architectural structure built against a wall or arch to support it

Flying Buttress

Columns on the outside of a structure that connects to the building near the top to support outer walls Eg. Notre Dame Cathedral, Westminster Abbey…

Stable

tending to maintain its shape and position

3 things for stability

friction, low center of gravity, and a large base

Friction

holds the structure in place when external forces are acting on it

Examples of Friction in action

brick layers, fasteners, “the agendas”

Low center of gravity

increase stability