CHAPTER 4 : THE VARIETY OF RESOURCES ON EARTH

4.1     THE         DIFFERENT    RESOURCES    ON     EARTH

1. Human  beings, animals and plants need food,   water,   air   and   shelter in order to survive. 
2.  The Earth has the resources needed to sustain  life. 
3.  The resources are air,   water,  soil,  minerals,  fossil    fuels  and  living   things.

Air

1.        Air is needed by all living things to survive.

2.        The atmosphere is a layer  of     air that envelops the Earth.

3.        Air is a mixture of gases. Air contains gases such as oxygen, nitrogen  and

carbon    dioxide.

4.        Oxygen and carbon dioxide are two very important gases that support life on

Earth.

         a.  Oxygen

i.  Used for respiration by living things   
ii.   Used in combustion of materials

iii. Used in industries

iv. Released during

     photosynthesis

b.  Carbon dioxide

i.  Used by green plants to carry out
    photosynthesis 

 ii.  Used in fire extinguishers

   iii. Released during respiration and combustion.

Water

1.        Water covers a total of about three quarters of the Earth.

2.       The sources of water are oceans, seas, rivers, lakes, rainfall and ground
           water

     

i.  It provides a medium for chemical process and body metabolism

ii. It is the main component of the blood

iii. It transports nutrient to all cell in the body

iv. It caries excretory products to the kidneys for excretion.

v.  It helps to control the body 
    temperature. 

 b.  To plants

i.  It helps to maintain the turgidity of plant cells.

ii. It is used in photosynthesis.

iii. Need for the germination of seeds.

Soil

1.        Soil refers to the outer layer of the Earth.

2.       Soil contains mineral matter, organic matter, air and water.

3.       The soil organic matter includes  Organic litter  such as fallen leaves, twigs,
          fruit, animal dropping etc. humus formed from the composition of organic
           litter. Microorganism living in the soil.

4.       Air and water are found in pore spaces between the soil particles.

5.       The presence of air and water in the soil makes soil a natural habitat for various types of plants and animal.

6.       Importance of soil

Source of minerals and fossil fuel

Source of clay for making pottery

Source of sand for making glass and cement

Base for agricultural activities

Foundation for construction of houses, building, road and other structures.

Living things

Importance of plants and animals

1.        Flora and fauna (plants and animals) are also natural resources that sustain
           life.

2.       Plants and animals are resources needed by human beings.

3.       We can obtain food, fuel, materials for making clothes and building materials from plants and animals.

4.       Green plants are able to make their own food by carrying out
           photosynthesis.

5.       Animal are not able to make their own food.

6.       Some animals for example, giraffes and elephants feed on plants.

7.       Some animals for example, tigers and snakes feed on other animals.

8.       Aquatic plants and animals are also important resources for sustaining life.

Mineral

1.        Minerals are inorganic substances found naturally on land and in seas or
           oceans.

2.       Examples of minerals are feldspar, quartz, iron, zinc, aluminium, tin, silver and gold.

3.       Some minerals for example aluminium and iron are mined because they can be used as raw materials in various industries.

Fossil Fuels

1.        Fossil fuels are formed from the remains

of animals and plants that have died millions of years.

2.       There are three types of fossil fuels;  petroleum, coal and natural gas.

3.       Coal and natural gas can be burnt as fuel directly after they mined.

4.       Petroleum can be separated into different parts by fractional distillation
          before  use.

5.       Products  of  fractional  distillation  are  petrol,  diesel,  kerosene  and liquefied petroleum gas.  ( LPG ).

ELEMENTS, COMPOUND AND MIXTURE

Elements.     PMR 04, 06

Elements are substances that are made up of only one type of particle . An element cannot be broken down into any simpler substances by physical or chemical methods .

Examples of elements are copper, carbon, iron, gold, sulphur and aluminium.   

There are more than 110 elements. 
 Element can be grouped into metals and non-metal.

Metal	PMR 06		Non-metal	PMR 06
There  are  91  types  of  metals  that  have been identified so far.			There are 19 types of non-metals that have been identified so far.
Examples   of   metal:   mercury,   potassium, sodium,  silver,  magnesium,  platinum,  lead, gold			Example  of  non-metal:  hydrogen,  carbon, nitrogen,    oxygen,     phosphorus,    sulphur, iodine, bromine, chorine

Metals Non metals Metals State (at room temperature) Non metals State (at room temperature) Aluminium Solid Carbon Solid Tin Solid Sulphur Solid Silver Solid Iodine Solid Potassium Solid Bromine Liquid Copper Solid Oxygen Gas Iron Solid Chlorine Gas Mercury Liquid Hydrogen Gas

Examples of metals and non metals
 

State at room temperature	Examples of non-metals
Solid	Carbon, sulphur, iodine, phosphorus
Liquid	Bromine
Gas	Hydrogen, argon, xenon, radon, helium, oxygen, neon, krypton, chlorine

Properties of metals and non-metals

metals	Non-metals
Have shiny surface	Have dull surface
Malleable (can be shaped)	Brittle
Ductile (can be stretched)	Not ductile
Have high melting point	Have low melting point
Good conductors of heat and electricity	Poor conductor of heat and electricity.

Compounds PMR 04, 08

1.        Compounds are substances that are made up of two or more types of particles.

These particles combine chemically according to a fixed proportion. Compounds Component elements Water Oxygen, hydrogen Carbon dioxide Carbon, oxygen Nitric acid Hydrogen, nitrogen, oxygen Sulphuric acid Hydrogen, sulphur, oxygen Sodium chloride (Common salt) Sodium, chlorine Baking soda Sodium, Hydrogen, carbon, oxygen Sugar Carbon, Hydrogen, oxygen Hydrochloric acid Hydrogen, chlorine Calcium chloride (lime water) Calcium, chloride, oxygen

3.       The particles can only be separated by chemical methods such as
          electrolysis or  by using strong heat and cannot be separated by 
           physically methods.

4.       For example    :     water   made up of one oxygen particle and two
      hydrogen particles.   Water can be broken down into hydrogen gas and
          oxygen gas by electrolysis.

5.       Carbon dioxide   is a compound made up of one carbon particle and two
       oxygen particles.

Mixtures

1.        Mixtures are substances that are made up of two or more types of
             particles  which combine physically.

2.        The different types of particles in a mixtures are not chemically combined and they can mix in any proportion.

Mixtures	Components
Air	Oxygen, hydrogen, water vapour, inert gases, dust, bacteria and other substances.
Salt solution	water, salt
Milo drink	Water, milo powder, sugar, milk
Petroleum	Petrol, kerosene, diesel, bitumen
Soil	Stones, sand, humus, minerals, mineral salts, air, water.

3.        The components of a mixture can be separated easily by physical
         methods such  as evaporation and filtration or by the use of magnet.

4.        Examples    :     blood, air,   soil,   coffee etc.

Comparison between an element, compound and mixture

Element                               Compound                                  Mixture

It is made up of only one type of particle

It   cannot    be   broken down  into                      simpler substances                  by             any chemical method.

It is made up of more than    one    type   of particle which combined chemically

New     substance     are formed.

New    properties    are formed.

Heat   is   released   or

absorbed.

Ration of component is fixed.

Can   be   separated   by

chemical            method

(electrolysis)

It can be broken down into  simpler substances by chemical method.

It is made up of more than one  type of particle which combined physically.

No    new    substance    are formed.

properties  of   components

are not formed.

Ration of component are not formed.

Can     be     separated     by physical method:

Example:     using     magnet, distillation,               filtration, evaporation …..

It can easily separated into its  components by physical method.

Example : Gold                        Example : Sugar                    Example : Soil

THE     IMPORTANCE           OF    EARTH'S     RESOURCES.

1.        Our basic needs are oxygen, food, water, clothing and shelter.

2.       The Earth`s resources fulfill our basic needs.

3.       Figure below gives an overview of the importance of the resources on Earth to human beings.

Air.

-        contains oxygen needed for respiration.

-        contains carbon dioxide needed for photosynthesis.

Water.

-        needed by our body systems to function normally.

-        needed for drinking, cooking, washing, cleaning and bathing.

Fossil Fuels.

-        used to generate electricity.

-        used to run motor vehicles.

-        used to run machines.

Minerals.

-        used as raw materials for buildings, machines, computers and other
        inventions.

-        needed by our body to function normally.

-        needed by plants to grow well.

Living Things.

-        animals provide us with food, clothing, companion and labour.

-        plants provide us with oxygen, food, clothing, building materials, pigments spices, colouring and medicines.

Soil.

-        support plants from falling.

-        supplies plants with minerals and water.

-        habitat to various types of living things.

-        Enables humans to carry out farming, mining and building constructions.

PRESERVATION          AND   CONSERVATION    OF    RESOURCES ON      EARTH

1.       Preservation means maintaining certain areas of Earth in their natural 
         condition.

2.       Preservation ensures that we do not lose our natural resources to
       development such us farming, industry, housing or tourism.

3.       Examples of efforts in preservation are the setting up of forest reserves, state parks, national parks and marine parks.

4.       These efforts ensure that the flora and  fauna in these protected areas
        would still be around for the future generations to see.

5.       Conservation means the sustainable use and management of Earth`s
          resources.

6.       Conservation also means using Earth`s resources wisely and not in wasteful
          ways.

7.       Conservation  of  resources  ensures  that  we  maintain  sufficient  quantities of resources for future generation to use.

THE       IMPORTANCE         OF      APPRECIATING    EARTH'S      RESOURCES       TO        HUMAN BEINGS

1.       We can show that we appreciate the importance of Earth`s resources by using the resources wisely and not in wasteful ways.

2.       You may practice reduce, reuse and recycle.

3.       Reducing means using less resources to ensure that will be there for our future use as well as for the future generations.

4.       Reusing refers to using discarded or unwanted materials to save   on nature`s resources.

5.       Recycling refers to the processing of waste materials to become useful things in order to save  Earth`s resources.

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