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Sosiale wetenskappe: aardrykskunde

Graad 7

Natuurgevare

Module 5

Droogtes

1. Droogtes

1.1 Die voorkoms en ontstaan van droogtes

1.1.1 Wat is droogtes?

‘n Droogte is ‘n aanhoudende en langdurige tydperk waartydens daar geen neerslag voorkom nie. Dit hang dus saam met ‘n gebrek aan water, maar dit lei nie altyd tot ‘n ramp nie. Dit is die verhouding tussen die gemeenskap en sy omgewing wat bepaal of ‘n droogte in ‘n ramp sal ontaard of nie. Eenmalige droogtes kom selde skielik voor. Dit bekruip ‘n gemeenskap gewoonlik oor ‘n tydperk van jare.

1.1.2 Waar kom droogtes voor?

Bestudeer figuur 1 op bl. 2. Dit is ‘n wêreldkaart wat aandui waar die meeste droogtes voorkom. Jy sal opmerk dat sekere lande meer deur droogtes getref word as ander, maar dat die Afrika-kontinent, Indië, China, Suid-Amerika en Australië die swaarste gebuk gaan onder ernstige droogtes.

Aktiwiteit 1:

Om die droë streke van suid-afrika te bestudeer

[lu 2.1]

  • Bestudeer figuur 2 oor die droë streke van Suid-Afrika en beantwoord dan die vrae wat volg.

a) Maak ‘n skatting watter persentasie van Suid-Afrika ‘n neerslag van minder as 500 mm per jaar kry.

b) Waar in Suid-Afrika is die waarskynlikheid die grootste dat droogtes sal voorkom? Hoekom?

c) Waar in Suid-Afrika is dit die minste waarskynlik dat droogtes sal voorkom? Hoekom?

d) Noem die maniere waarop ‘n boer in die Noord-Kaap voorsorg kan tref vir toekomstige droogtes.

1.1.3 Wat veroorsaak droogtes?

Water is noodsaaklik vir lewe op aarde. ‘n Droogte ontstaan as gevolg van ‘n tekort aan water. Baie mense dink dat ‘n droogte net ontstaan omdat dit nie reën nie. ‘n Afname in neerslag veroorsaak wel droogtes, maar dit is nie die enigste oorsaak nie.

Bestudeer tabel 1 wat aantoon hoe ander faktore rampspoedige toestande wat met droogtes verband hou, kan veroorsaak.

Tabel 1:

Klimaatsverandering het dus wel te doen met droogtes, maar swak omgewingsbestuur het ‘n groter invloed op die rampspoedige invloed van ‘n droogte.

1.2 Die uitwerking (gevolge) van droogtes op die lewens van mense en hul sosio-ekonomiese aktiwiteite

Gedurende ‘n tydperk van ongeveer 10 jaar word ongeveer 60 miljoen mense wêreldwyd deur droogtes geaffekteer en hierdie syfer is steeds besig om te styg. In die 1990’s is 35 miljoen mense in Afrika alleen deur droogtes geraak. Wat sal die situasie wees in die jare wat voorlê?

Bestudeer die volgende lys van gevolge van droogtes:

geen wisselbou

misoeste

hongersnood: minder voedsel geproduseer

lewensverlies

putte droog op as gevolg van verlaagde watertafel

lewende hawe word op groot skaal geslag: vleispryse daal

hidro-elektriese aanlegte kan ophou werk: kragpryse styg

ongeskoolde arbeiders verdien min inkomste: armoede

waterbeperkings word ingestel

nywerhede word deur ‘n gebrek aan water benadeel

plantegroei vrek en verdwyn

stofkomme ontstaan op kaal grond en lugbesoedeling vererger

werkers verloor hul poste en het geen inkomste om van te lewe nie: werkloosheid veroorsaak misdaad

groeiende bevolking plaas meer druk op die omgewing en ‘n rampspoedige mallemeule ontwikkel

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Aardrykskunde graad 7. OpenStax CNX. Sep 09, 2009 Download for free at http://cnx.org/content/col11020/1.1
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