Balsa
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224099314
2008-07-07T08:45:36Z
75.36.187.149
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{{for|the e-mail client|Balsa (e-mail client)}}
{{for|the Roman town|Balsa (Roman town)}}
{{Taxobox
| name = Balsa
| image = Ochroma pyramidale1FrancesWHorne.jpg
| image_width = 200 px
| image_caption = Painting by Frances W. Horne from the Flora Borinqueña
| regnum = [[Plant]]ae
| divisio = [[Flowering plant|Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Malvales]]
| familia = [[Malvaceae]] ([[Bombacaceae]])
| genus = '''''Ochroma'''''
| genus_authority = Sw.
| species = '''''O. pyramidale'''''
| binomial = ''Ochroma pyramidale''
| binomial_authority = (Cav. ex Lam.) Urb.
}}
'''Balsa''' (''Ochroma pyramidale'', synonym ''O. lagopus'') is a large, fast-growing [[tree]] that can grow up to 30[[metre|m]] (100[[foot (unit)|ft)]] tall, native to [[tropical]] [[South America]] north to southern [[Mexico]]. It is [[evergreen]], or dry-season [[deciduous]] if the dry season is long, with large (30–50 [[centimetre|cm]], 12-20 [[inch|in]]) weakly palmately lobed leaves. The name ''balsa'' derives from [[Spanish language|Spanish]] for a [[raft]]. Despite being very soft, balsa is classified as a [[hardwood]], and is the softest commercial hardwood.
The [[timber]] is very soft and light with a coarse open grain. The [[density]] of dry balsa [[wood]] ranges from 100–200 kg/m³ (6.24-12.49 lb/ft³), with a typical density of about 140 kg/m³ (8.74 lb/ft³) (about one third the density of other hard woods). This makes it a very popular material for [[model building]] and buoyancy materials (lifebelts, etc.), and was famously used by [[Thor Heyerdahl]] in his raft [[Kon-Tiki]]. It is also a very popular material to use when making wooden [[crankbait]]s for fishing, as it is low density but high in strength. Balsa wood is used to make very light, stiff structures in [[balsa wood bridges|model bridge tests]] and for the construction of light wooden [[aeroplane]]s, most famously the [[World War II]] [[de Havilland Mosquito]]. It is also used in the [[floorpan]] of the [[Chevrolet Corvette|Chevrolet Corvette Z06]] sandwiched between two sheets of carbon fibre. In table tennis blades, a balsa layer is typically sandwiched between two pieces of thin [[plywood]]. Balsa wood is also used in [[laminates]] with [[glass-reinforced plastic]] (fiberglass) for making high-quality [[balsa surfboards]] and the [[deck (ship)|decks]] and [[topsides]] of many types of boats, especially pleasure craft under 30[[metre|m]] (100 [[foot (unit)|ft]]) in length.
Today balsa is the most favoured raw material for wind rotor blade designers. Balsa wood is used as core material in composites especially wind energy rotor blades for getting the required strength on leading edge of rotor blade. But availability of balsa is a critical issue today as plantation is limited to only North American region.
<gallery>
Image:balsa.jpg|Three different sizes of balsa wood used for hobby purposes
Image:balsa_airframe.jpg|Frame of a model airplane constructed entirely of balsa wood
</gallery>
==See also==
*[[Paulownia]]
==References==
*[http://www.balsaworld.com Technical Description, History, Facts, Specs]
* [http://www.cds.ed.cr/teachers/harmon/page21.html Species description]
* [http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?25473 Germplasm Resources Information Network: ''Ochroma pyramidale'']
* [http://www.tfts.org/ochroma_lagopus.htm Photo of foliage and flower]
* [http://www.kon-tiki.no/Ny/Dok_eng/e_start.html Kon-Tiki museum website]
* [http://www.piedrablanca.org/raftingEcuador.htm Balsa rafting in Ecuador]
[[Category:Malvaceae]]
[[Category:Wood]]
[[Category:Trees of Trinidad and Tobago]]
[[da:Balsatræ]]
[[de:Balsabaum]]
[[es:Balsa (árbol)]]
[[fr:Balsa (arbre)]]
[[he:בלזה]]
[[ja:バルサ]]
[[pl:Ogorzałka wełnista]]
[[pt:Balsa (madeira)]]
[[ru:Бальза (дерево)]]
[[sl:Balza]]
[[fi:Balsapuu]]
[[sv:Balsa]]