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Case study : water conservation

Refer to [link] and then answer the following questions:

  1. Explain what is meant by...
    1. surface water
    2. ground water
  2. Which water management area has the...
    1. lowest surface water yield?
    2. highest surface water yield?
    3. lowest total yield?
    4. highest total yield?
  3. Look at the country's total water requirements for 2000 and the total available yield .
    1. Calculate what percentage of the country's water yield is already being used up.
    2. Do you think that the country's total water requirements will increase or decrease in the coming years? Give a reason for your answer.
  4. South Africa is already placing a huge strain on existing water resources. In groups of 3-4, discuss ways that the country's demand for water could be reduced. Present your ideas to the rest of the class for discussion.


  • Water is critical for the survival of life on Earth. It is an important part of the cells of living organisms and is used by humans in homes, industry, mining and agriculture.
  • Water moves between the land and sky in the water cycle . The water cycle describes the changes in phase that take place in water as it circulates across the Earth. The water cycle is driven by solar radiation.
  • Some of the important processes that form part of the water cycle are evaporation, transpiration, condensation, precipitation, infiltration and surface runoff. Together these processes ensure that water is cycled between the land and sky.
  • It is the microscopic structure of water that determines its unique properties.
  • Water molecules are polar and are held together by hydrogen bonds . These characteristics affect the properties of water.
  • Some of the unique properties of water include its ability to absorb infra-red radiation, its high specific heat, high heat of vaporisation and the fact that the solid phase of water is less dense that its liquid phase.
  • These properties of water help it to sustain life on Earth by moderating climate, regulating the internal environment of living organisms and allowing liquid water to exist below ice, even if temperatures are below zero.
  • Water is also a good solvent . This property means that it is a good transport medium in the cells of living organisms and that it can dissolve gases and other compounds that may be needed by aquatic plants and animals.
  • Human activities threaten the quality of water resources through pollution and altered runoff patterns.
  • As human populations grow, there is a greater demand for water. In many areas, this demand exceeds the amount of water available for use. Managing water wisely is important in ensuring that there will always be water available both for human use and to maintain natural ecosystems.

Summary exercise

  1. Give a word or term for each of the following phrases:
    1. The continuous circulation of water across the earth.
    2. The change in phase of water from gas to liquid.
    3. The movement of water across a land surface.
    4. The temperature at which water changes from liquid to gas.
  2. In each of the following multiple choice questions, choose the one correct answer from the list provided.
    1. Many of the unique properties of water (e.g. its high specific heat and high boiling point) are due to:
      1. strong covalent bonds between the hydrogen and oxygen atoms in each water molecule
      2. the equal distribution of charge in a water molecule
      3. strong hydrogen bonds between water molecules
      4. the linear arrangement of atoms in a water molecule
    2. Which of the following statements is false ?
      1. Most of the water on earth is in the oceans.
      2. The hardening of surfaces in urban areas results in increased surface runoff.
      3. Water conservation is important because water cannot be recycled.
      4. Irrigation is one of the largest water users in South Africa.
  3. The sketch below shows a process that leads to rainfall in town X. The town has been relying only on rainfall for its water supply because it has no access to rivers or tap water. A group of people told the community that they will never run out of rainwater because it will never stop raining .
    1. List the processes labelled P 1 and P 2 that lead to rainfall in town X.
    2. Is this group of people correct in saying that town X will never run out of rainwater? Justify your answer using the sketch. Recently, the amount of rainwater has decreased significantly. Various reasons have been given to explain the drought. Some of the community members are blaming this group who told them that it will never stop raining.
    3. What scientific arguments can you use to convince the community members that this group of people should not be blamed for the drought?
    4. What possible strategies can the community leaders adopt to ensure that they have a regular supply of water.

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
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
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
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.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Siyavula textbooks: grade 10 physical science. OpenStax CNX. Aug 29, 2011 Download for free at http://cnx.org/content/col11245/1.3
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