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Natuurwetenskappe

Graad 5

Die aarde en die heelal

Module 23

Gronderosie

Aktiwiteit:

Om oor gronderosie en goeie boerderymetodes te kan praat

[lu 1.3; 2.1; 2.2]

Gronderosie

  • Het jy al ooit op ‘n winderige dag langs die see gestap en gevoel hoe sandkorrels teen jou bene waai? Dit gebeur gereeld in die natuur dat die wind gronddeeltjies, maar veral sand, optel en na ‘n ander area verplaas.

Groepopdrag:

Julle benodig : ‘n vierkantige houtblokkie, ‘n haardroër, growwe en fyn sand, en ‘n leë ysbakkie.

Plaas ‘n hopie sand op die houtblokkie.

Plaas die blok en die ysbakkie teenmekaar.

Hou die haardroër naby die sand en blaas die sand in die ysbakkie in.

Skryf jou waarneming neer.

Kom ons pas toe wat jy nou geleer het.

  • Gedurende ‘n stofstorm word die fynste gedeeltes sand hoog deur die lug gedryf, terwyl die growwer deeltjies ongeveer ‘n meter bokant die grond beweeg. Op hierdie wyse word duine by die see of in ‘n woestyn gedurig verskuif. Ongelukkig kan die wind egter op hierdie wyse ook gronderosie veroorsaak. As oorbeweiding plaasvind, plante uitgeroei word of die veld op die verkeerde tyd gebrand word, word die boonste laag grond blootgestel en kan die wind erosie veroorsaak.
  • Water kan nog ernstiger gronderosie veroorsaak as daar byvoorbeeld êrens teen ‘n skuinste nie voldoende plante groei nie.

Goeie boerderymetodes

Beantwoord nou die volgende vrae:

1. Hoekom moet natuurlike plantegroei nie sonder meer verwyder word nie?

2. Hoekom kan voetpaadjies nadelig vir die veld wees?

3. Ervare veeboere hou daarvan om baie kampe te maak en om water na elke kamp aan te lê.

(a) Hoekom?

(b) Hoe het boere in vroeër jare, toe hulle nog nie materiaal gehad het om kampe te maak nie, die probleem opgelos?

4. Kyk na die skets wat wys dat ‘n boer wat ‘n wingerd, vrugteboord of mielieland op ‘n heuwelagtige plaas wil aanlê, die grond op twee maniere kan voorberei.

Sê watter een van die twee maniere jy sou aanbeveel en verduidelik hoekom.

Assessering

LU 1

WETENSKAPLIKE ONDERSOEK Die leerder is in staat om met selfvertroue op weetgierigheid oor natuurlike verskynsels te reageer, en om binne die konteks van wetenskap, tegnologie en die omgewing verbande te ondersoek en probleme op te los.

Dit is duidelik wanneer die leerder:

1.1 ondersoeke beplan;

1.2 ondersoeke uitvoer en data versamel;

1.3 data evalueer en bevindinge kommunikeer.

LU 2

KONSTRUKSIE VAN WETENSKAPKENNIS Die leerder ken, interpreteer en pas wetenskaplike, tegnologiese en omgewingskennis toe.

Dit is duidelik wanneer die leerder:

2.1 betekenisvolle inligting onthou;

2.2 inligting kategoriseer en eie reëls vir kategorisering verduidelik.

Memorandum

Boerderymetodes

  1. Erosie, suurstof-/koolstofdioksiedbalans (samestelling van lug, osoonlaag), diere is afhanklik van plante as voedsel, vir beskerming, ens.
  2. Plante word doodgetrap, grond word hard, geen humus, as dit baie reën, spoel boonste laag weg, erosie begin.
  3. Redes vir kampe
    1. Voorkom oorbeweiding op bepaalde plekke, en vorming van voetpaadjies as diere altyd na dieselfde waterbron elders moet loop.
    2. Getrek na dele waar nog weiveld en water is.

4. Die metode waar die ploegwerk dwars teen die helling gedoen word, aangesien dit verspoeling en erosie voorkom.

Questions & Answers

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s. Reply
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SUYASH Reply
for screen printed electrodes ?
SUYASH
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s. Reply
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Ebrahim
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Ebrahim
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s.
Graphene has a hexagonal structure
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Cied
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I start with an easy one. carbon nanotubes woven into a long filament like a string
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Porter
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AMJAD
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
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AMJAD
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AMJAD
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In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
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Damian
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Damian
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Azam
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Uday
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Prasenjit
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Prasenjit Reply
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Source:  OpenStax, Natuurwetenskappe graad 5. OpenStax CNX. Sep 23, 2009 Download for free at http://cnx.org/content/col10980/1.2
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