<< Chapter < Page Chapter >> Page >

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

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
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Natural sciences grade 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11050/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Natural sciences grade 8' conversation and receive update notifications?

Ask