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Natural science

Grade 9

The earth, galaxies and space programmes

Module 13

The earth and its features


  • Inner core - very dense, unbelievably hot
  • Outer core - in a molten state
  • Mantle - molten rock
  • Crust - solid rock (very thin)

Activity: diagram

Draw a circle and draw in these layers . Use different colours to indicate the different layers.

Assessment of diagram:

Did you indicate the layers correctly?

[LO 2.3]

  • The core comprises iron and nickel, and the crust consists of oxygen and silicon.
  • In the soft mantle there are silicates, oxides and sulphates.

why does the earth rotate?

  • The earth rotates because it falls in the direction of the sun. The sun’s force of gravity causes the earth to revolve around sun and rotate on its axis.
  • It is like a ball rolling down a hill.
  • The earth revolves once around its own axis every 24 hours.
  • Each planet in the solar system also revolves around the sun in its own orbit.
  • The earth takes 365¼ days to complete one orbit. This is also called a revolution or, in general terms, a year (‘ earth-year ’).
  • It takes each planet a specific number of earth-years to complete one revolution around the sun.
  • Mars, has a revolution time of 1,9 earth-years.
  • Jupiter takes 11,9 earth-years and Pluto 247,7 earth-years to orbit the sun.

how big is the earth?

split up into groups for the next activity.

Activity: discussion

information on the earth:

Circumference around poles: 40 008 km

Diameter at poles: 12 714 km

Circumference at Equator: 40 075 km

Diameter at Equator: 12 714 km

1. What can you deduce from these statistics regarding the shape of the earth? What could be the explanation for this?

2. Who was Eratosthenes and what did he say 2 000 years ago about the shape of the earth? Discuss this in groups and write down the answers. ( www.union.edu/PUBLIC/GEODEPT/hallocher/sciencelab/Labs/ ND2/LN2.htm)

Assessment of DISCUSSION:

[LO 1.2; LO 1.3]

why is life possible on earth?

  • It is the only planet in our solar system where there is an atmosphere with oxygen and where there is surface water. Life as we know it requires oxygen and water!
  • The oceans take up about 70% of the earth’s surface.
  • The earth’s atmosphere comprises the following gases:
  • oxygen (21%)
  • nitrogen (78%)
  • argon (0.9%)
  • carbon dioxide (0.03%)

Activity: circle diagram

Draw a circle. Use different colours, indicating the composition of the atmosphere in percentages in the circle.

Work out the sectors mathematically.

Assessment of circle diagram:

Is your diagram correct? [LO 2.4]


LO 1: Scientific investigations:

The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

This is evident when the learner:

1.2 conducts investigations and collects data;

  • evaluates data and communicates findings.

LO 2: Constructing Science Knowledge:

The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

This is evident when the learner:

  • interprets information;

2.4 applies knowledge.


The earth and its features


1. The shape of the earth is not altogether round. It is slightly flattened at the poles because its rotation is faster at the equator

2. A Greek philosopher who was the person to show that the earth is round by means of a calculation.


The atmosphere consists of 21% oxygen, 78% nitrogen and 0.03 % carbon dioxide, and 0.9 % argon

In diagram: atmospheric gases

Questions & Answers

find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
I know this work
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
is it a question of log
I rally confuse this number And equations too I need exactly help
But this is not salma it's Faiza live in lousvile Ky I garbage this so I am going collage with JCTC that the of the collage thank you my friends
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
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?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
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
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
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
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
what is system testing
what is the application of nanotechnology?
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
anybody can imagine what will be happen after 100 years from now in nano tech world
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
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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, Natural sciences grade 9. OpenStax CNX. Sep 15, 2009 Download for free at http://cnx.org/content/col11069/1.1
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