Design & Technology - 0445 CIE

Timbers And Boards

Gbogbo ọrọ náà

Wood is one of the oldest engineering materials and still one of the most useful. It is a renewable, workable, surprisingly strong material that comes straight from a living tree, and the way a tree grows leaves clues in the wood - the grain, the rings, the knots - that a designer learns to read. The first and most important split is between softwoods from fast-growing evergreen trees and hardwoods from slower broadleaved trees, a classification based on the type of tree, not simply on how hard the wood feels.

This note covers the 0445 Materials-option timber objectives: classifying natural timbers, their stock forms, properties, environmental impact and uses; the named softwoods (cedar, pine, redwood, spruce) and hardwoods (oak, mahogany, meranti, jelutong); the family of manufactured boards including plywood, chipboard and MDF; and a clear-eyed comparison of when a manufactured board beats solid timber and when it does not.

Ebumnobi

  1. demonstrate knowledge of natural timbers and understand their classification, stock forms, properties, environmental impact and uses
  2. demonstrate knowledge of softwood timbers, for example: - cedar - pine - redwood - spruce - local equivalents
  3. demonstrate knowledge of hardwood timbers, for example: - oak - mahogany - meranti - jelutong - local equivalents
  4. demonstrate knowledge of manufactured boards, for example: - plywood - chipboard - fibre-based boards including medium density fibreboard (MDF) - local equivalents
  5. understand the advantages and disadvantages of working with manufactured boards compared with natural timbers.

Akọmọ Ojú-ẹkọ

Natural timber is divided into two groups by the kind of tree it comes from. Softwoods come from coniferous trees - evergreens with needles and cones, such as pine and spruce. They grow relatively quickly and straight, so they are cheaper and more readily available. Hardwoods come from deciduous, broadleaved trees such as oak and mahogany that mostly grow slowly, giving denser, often stronger and more durable wood that costs more. The labels can mislead: balsa is botanically a hardwood yet is one of the softest woods of all, and yew is a softwood that is fairly hard. The classification is about tree type, not the feel of the wood.

Ọ dị na ngwa Green Bridge

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Ayẹwo Ẹkọ

Ekele diri gi maka imecha ihe karịrị na Timbers And Boards. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.

Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.

Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.

  1. Which feature defines a hardwood? A. The wood is always physically hard B. It comes from a deciduous broadleaved tree C. It is always darker than a softwood D. It cannot be used for furniture Answer: B
  2. Which softwood is naturally durable and most suitable for outdoor cladding without heavy treatment? A. Spruce B. Pine C. Cedar D. Jelutong Answer: C
  3. Why does plywood have an odd number of veneers? A. To make it cheaper B. So the grain of the outer veneers runs the same way and the panel stays balanced and flat C. To allow it to be bent into curves D. So it can be used outdoors Answer: B
  4. Which is a correct disadvantage of MDF compared with solid timber? A. It cannot be painted B. It is more expensive than oak C. It swells and is weakened if it gets wet, and its dust is a health hazard D. It is too strong to machine Answer: C
  5. Why are brass or stainless steel screws preferred to ordinary steel screws when working with oak? A. Oak is too soft for steel screws B. The tannin in oak corrodes steel and causes blue-black staining C. Steel screws are more expensive D. Oak cannot be drilled Answer: B

Ọ dị na ngwa Green Bridge

Budata ngwa Green Bridge CBT na ekwentị maọbụ kọmputa gị iji nweta akwụkwọ ndụmọdụ zuru oke, ajụjụ mmụta, na ndị ọzọ.

Akwụkwọ ndụmọdụ zuru oke nwere eserese
Onye inyeaka mmụta AI
Mụọ n'ụzọ na-enweghị ịntaneti, oge ọbụla, ebe ọbụla
Ọ dị na Android, Windows, macOS, na Linux

Ọ dị na ngwa Green Bridge

Budata ngwa Green Bridge CBT na ekwentị maọbụ kọmputa gị iji nweta akwụkwọ ndụmọdụ zuru oke, ajụjụ mmụta, na ndị ọzọ.

Akwụkwọ ndụmọdụ zuru oke nwere eserese
Onye inyeaka mmụta AI
Mụọ n'ụzọ na-enweghị ịntaneti, oge ọbụla, ebe ọbụla
Ọ dị na Android, Windows, macOS, na Linux

Meecha Ajụjụ Ule Ọmarịcha

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