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Natural sciences

Grade 4

Planet earth and the universe

Module 40

The earth and its movement


Talking about the earth



  • This picture shows what the earth looks like from space. Space travellers tell us that the earth looks like a large, shining ball in the dark sky. It looks as if the surface of the earth is covered in clouds. The blue areas that we see are the oceans of our planet. The earth may seem small when we look at it from the moon, but if you had to dig through the middle of the earth to the other side, you would have to dig a tunnel of 6 400 km long!
  • The earth is the only planet on which life is possible, because it has a supply of air, water and soil. Only a quarter (approximately) of the earth’s surface is land, the rest is water in the form of the oceans, rivers, lakes, etc. The land consists of deserts, forests, grasslands, mountains and ice.

Divide the class into eight groups. You are going to make posters about this wonderful earth and put them up in the class. Use old magazines to make a collage on an A3 sheet of paper.

Group 1: Oceans

Oceans are made up of salt water and they cover a large part of the earth. Wind creates waves and keeps the water in motion all the time. The average depth of the ocean is 4 000 m. Plants and fish live even deep down in the sea.

Group 2: Deserts:

These are dry areas where it hardly ever rains. It is usually sandy, with rocks and stones here and there. There is very little water and therefore very few plants grow. The Sahara, in Africa, is the largest desert in the world.

Group 3: Polar Regions:

The Polar Regions are at the North and South Poles. They are covered in snow and ice and are the coldest places on earth.

Group 4: Grasslands:

These are relatively flat areas that receive very little rain. There are few trees, but many animals such as buck, zebras, giraffes, etc. live here. After rains have fallen there usually is much grass that can be eaten by the animals.

Group 5: Forests:

These are areas where trees grow very densely. Many animals and snakes and many types of birds and spiders are found in these forests.

Group 6: Rivers:

The longest river in the world is the Nile, which is approximately 6 671 km long. Rivers usually have their sources in mountains and may have waterfalls. Rivers usually have fresh water, sometimes fish are found in them and towns and factories are often developed alongside them. Rivers usually end at the sea and often form deltas where the river flows into the sea. Can you explain what a delta is?

Group 7: Mountains:

The highest mountain in the world is Mount Everest, which is 8 848 metres high. It is very cold on the highest peaks of such high mountains.

Group 8:Plant and animal life:

We find plants and animals everywhere on earth.


Investigating and describing the movement of the earth

[lo 1.3, 2.1]

What causes day and night?

Use a ball and paste a map of South Africa on it. This ball represents the earth. You could also use a real globe. Use a torch to represent the sun. Spin the ‘earth’ to demonstrate the change from day to night. One full turn takes 24 hours (1 day). At the same time move the ‘earth’ around the ‘sun’ to demonstrate how the seasons come about. This takes 365¼ days (1 year).

Use the following key words to describe how day and night occur. Write a paragraph on the lines that are provided:

Key words: earth, spin, 24 hours, axis, sun, day, night


LEARNING OUTCOME 1: SCIENTIFIC INVESTIGATIONSThe 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.

Assessment Standard

We know this when the learner

  • leads investigations and collects data.

1.3 evaluates data and provides feedback on observations.

LEARNING OUTCOME 2 : CONSTRUCTING SCIENCE KNOWLEDGE The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard

We know this when the learner

2.1 recalls significant information.


This is a very pleasurable activity where learners learn to work together and to look at magazines with enquiring minds in order to find the right pictures for their collages. These can look beautiful in class or in a corridor.

Earth's movement

  • How do day and night happen?

Use the following key words to describe how day and night happen. Write a paragraph on the following lines:

Key words : earth, revolves, 24 hours, axis, sun, day, night

The earth revolves around its own axis every 24 hours . When any part of the earth faces the sun , it is day ; when it faces away from the sun , it is night .

Questions & Answers

so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
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.
what is biological synthesis of nanoparticles
Sanket 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 4. OpenStax CNX. Sep 18, 2009 Download for free at http://cnx.org/content/col11096/1.1
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