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Natuurwetenskappe

Graad 8

Omgewing en interaksies

Module 39

Ekologiese probleme en oplossings

Baie van die probleme wat tans in die natuur ervaar word, is deur die mens veroorsaak.

Die mens se grootste knelpunte lê ongetwyfeld in wat kortom as die HIPPO dilemma bekend staan.

H Habitatverlies

I Indringerspesies

P (Pollution) besoedeling

P Populasietoename (Bevolkingstoename)

O Oorverbruik

Aktiwiteit 1:

Om die mens se rol in ekologiese probleme te besef en te poog om oplossings te soek

[lu 1.1; 1.2; 1.3; 2.2; 3.1]

Die mens is skuldig aan al vyf. Ons ontbos en kap woude af omdat ons paaie, huise en nywerhede wil oprig. Dink maar net aan die Amasone: ’n geweldige verlies aan plante wat moet bydra tot ons suurstofvoorrade in die lug.

Ons laat toe dat vreemde spesies, veral plante en insekte, areas binnedring waar hul geen natuurlike vyande het nie. Dit hou groot gevare in vir die inheemse spesies wat dan maklik verdring word deur die aggressiewe vreemde spesies. Dink maar net aan Rooikrans op die Kaapse Vlakte of die swartwattelbome langs die riviere in die Boland.

Vreemde bye verdring ook ons eie soorte bye.

Besoedeling is uiteraard een van die grootste probleme. Ons besoedel die lug, die grond en die water met chemikalieë, olie, plastiek, ander bio-onafbreekbare stowwe en met geraas.

Dit alles word vererger deurdat ons bevolkingsgetalle daagliks toeneem (reeds behandel in die Biodiversiteit-module).

Die groot bevolkingsgetalle veroorsaak dus ook oorverbruik van alle natuurlike hulpbronne. Die skaarsste een is natuurlik WATER .

Berei ’n drie-minute praatjie oor die volgende onderwerp voor: “Die mens is nie deel van ’n ekosisteem nie en sodra hy by ’n ekosisteem betrokke raak, versteur hy die sisteem.”

  • Skryf die hoofpunte van jou praatjie hieronder neer.

[LU 2.2]

Aktiwiteit 2:

Die volgende projek is op die sinvolle benutting van water as ons belangrikste natuurlike hulpbronne gerig

Projek: WATER-OUDIT BY DIE SKOOL

Verdeel in groepe van vier. Beplan die volgende:

1. hoe julle die waterverbruik in julle skool gaan bepaal;

2. hoe julle die bevindinge in ’n verslag gaan voorstel;

3. watter moontlike gevalle van watervermorsing julle gaan ondersoek;

4. watter aanbevelings julle gaan maak.

  • Jou onderwyser gaan ’n datum vir die inhandiging van die verslag bepaal.
  • Elke groep dra sy verslag aan die klas voor.
  • ’n Samevatting van die finale bevindinge kan aan die bestuur van die skool voorgelê word. ’n Klasbespreking oor watter aanbevelings voorgelê moet word, sal nuttig wees.
  • Die volgende ondersoeke kan jou help met die navorsingstaak:

1.watervermorsing by krane

Julle kan die waterverbruik van die gemiddelde leerling met behulp van die volgende stappe bepaal:

verdeel in groepe van vier; julle benodig ’n groot maatsilinder, ’n stophorlosie en ’n emmer;

een persoon in die groep neem tyd;

twee persone drink;

een persoon noteer waarnemings in ’n tabel.

Wanneer die stophorlosie begin, draai die kraan normaal oop en drink met jou hand soos jy normaalweg sou drink terwyl jy die verspilde water in die emmer opvang. Die persoon wat tyd hou, sal jou sê wanneer jy na 30 sekondes moet stop. Een persoon gooi nou die vermorsde water in die maatsilinder en meet hoeveel water verlore gegaan het. Herhaal prosedure vir tweede persoon en verkry ’n gemiddeld.

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
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
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Natuurwetenskappe graad 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11049/1.1
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