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Natural sciences

Grade 8

Environment

Module 38

The role of water in nature and its role as a resource

Activity:

To be able to explain the value of water and the water cycle

[lo 1.3; lo 2.3; lo 2.4]

Our planet looks blue from outer space because of the water on its surface.

Water is indispensable for life on our planet. Without water ecological survival would not be possible.

Our planet is equipped with a certain quota of water – just as a spaceship would be. The water is not replenished from outer space, but has to CIRCULATE. Thus the WATER CYCLE is an extremely important aspect of nature. It is also most effective if humans do not disturb it.

The Water Cycle

Draw a representation of the water cycle as you understand it. Use explanatory captions. Use the table on the following page as a guideline.

Assessment of WATER CYCLE SKETCH

Were you able to represent basic components and definitions GRAPHICALLY?

[LO 2.3]

El Niño, droughts and floods

  • On comparing the rainfall statistics of South Africa to those of other countries, one sees very clearly that South Africa is an arid country.
  • Only some of the larger rivers flow permanently.
  • Furthermore, our climate and rainfall patterns are determined by phenomena such as El Niño. This is a world-wide weather phenomenon and precautions must be taken to cope with it.

1. Find out more about El Ni ñ o and report back to the class. Make a brief summary of your notes.

2. Find articles on droughts and floods in South Africa and bring them to class. Swap information and articles. Make notes on the subject.

[LO 1.3]

Use graph paper and draw two column graphs in different colours to represent the rainfall patterns in the two provinces.

Activity:

To look into the value of water and its use in and around the house

[lo 2.3; lo 3.2]

Water consumption at home

Ask your parents or guardians for their municipal accounts.

  • Write down your domestic water consumption for six months (three summer months and three winter months).

Summer months: 1. ......................... 2. ......................... 3. .........................

Winter months : 1. ......................... 2. ......................... 3. .........................

  • Do you think that your water consumption is excessive?

Saving water at home

How can your family contribute towards saving water? What can YOU do?

  • Make a list of your best suggestions:

Assessment of CLASS DISCUSSION

Were you able to make feasible suggestions concerning WATER CONSERVATION?

[LO 3.2]

Activity:

To examine the adaptations of plants and animals with regard to water shortage

[lo 1.3; lo 2.3]

Plants:

  • In a previous module reference was made to plants that can be classified into three groups, according to their water requirements.

Name the three groups and give an example of each.

  • Plants have numerous adaptations and survival strategies, especially with regard to water shortages.
  • Xerophyte leaves have been modified to thorns in cases such as the cactus plant groups. Other plants, such as the aloe, about which you had to do a project, store a great deal of water in their fleshy leaves through protein bonding.
  • The leaves of mainly xerophytes are thick and fleshy and unpleasant or bitter to the taste to deter animals from eating them. In this way they prevent the plant from being robbed of its valuable moisture.
  • The leaves of plants that have been adapted to arid conditions for survival are often sessile (no leafstalk) and they are arranged in such a way that any water that collects on the leaf (e.g. dew) will run down the stem so that the roots can absorb it.
  • The leaves of some other plants roll up when it is very dry, so that evaporation is limited. For example, see what the leaves of the maize plant look like when it hasn’t rained for a long time.

Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
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SUYASH Reply
for screen printed electrodes ?
SUYASH
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s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
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Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
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Cied
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abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
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Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
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
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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
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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Prasenjit Reply
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Source:  OpenStax, Natural sciences grade 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11050/1.1
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