THE VARIETY OF RESOURCES ON EARTH

By the end of this chapter, you should be able to :

# know the different resources on earth

# understand elements, compounds and mixture

# appreciate the importance of variety of Earth’s resources

• Air

• Water

• Soil

• Living organisms

• Minerals

• Fossil fuel

The various resources on earth

The various resources on earth

we need and use.

Water, air , soil and living organisms are four important basic resources.

These sustain plant & animal (including human) life.

waterWater is very important basic resource.

live & grow.

Living processes

70% of the Earth’s surface.

The important of water to human beings & animals

Dissolves & transports digested food to all parts of the body.

Transport oxygen

Blood is made up mostly of water

Important in excretion – dissolves & gets rid of waste material.

Controls body temperature

The bodies of most living organisms contain a high percentage of water.

60% - 95% of body weight of living organisms is made up of water

jellyfish 96%

pineapple 85%

Human being 70%

fish 68%

Keep the lungs moist- necessary for the exchange of gases

Dilutes blood- flow to all parts of the body

Supports & maintains the body shape of invertebrate & helps invertebrate to move. (Amoeba, earthworm, leeches)

Daily activities- cooking, washing, mining, transport

Without water a person will die of dehydration

Important of water to plants:The germination of seeds

Helping plant cells to keep their shape

Cooling plants through the process of transpiration

Dissolving & transporting mineral salts from the root to other parts of the plant

Photosynthesis

growth

AIR

Air is a mixture of gases- nitrogen, oxygen, carbon dioxide, rare gases & water vapour.

Oxygen is needed by all living things for respiration.

During respiration oxygen is used to oxidise food for release energy that are needed to carry out all activities.

Oxygen also needed for combustion. Fuels will not burn without oxygen. Burning produces carbon dioxide, water vapour, heat energy & light energy.

Carbon dioxide is used in photosynthesis in plants to make their own food .

Oxygen are release during photosynthesis. Therefore, photosynthesis is important to maintaining the oxygen & carbon dioxide contents in air.

photosynthesis

Carbon dioxide

oxygen

combustion

respirationThe gases used in photosynthesis,

respiration & combustion

SOILMade up of small bits of rock & decayed organisms.

Contains water, air, humus & mineral salts.

Habitat for many plants & animals.

All green plants are dependent on soil for their supply of water & essential mineral salts, as well as the air needed for the respiration of their roots.

Humus is among the richest & darkest of soils.

An organic substance that consist of dead organic matter derived from plants & animals.

Necessary for the growth of healthy plants.

Mineral salts dissolve in soil water, these are absorbed by plant roots.

Necessary for plants grow well.

Example : phosphates, nitrates, calcium, magnesium & potassium.

Soil is needed for the formation of fuels such as petroleum, natural gas & coal.

Human beings use soil for many purposes, such as:

(a) the construction of building

(b) agriculture

(c) making ceramics, glass, cement & bricks

(d) mining metals, mineral salts & chemical substances

Living things Plants & animals are basic resources for human beings. They

provide us with:

(a) Food

(b) Clothes

(c) Building materials

(d) fuel

FoodHuman beings need food to obtain energy . This energy is needed to do work, to grow & maintain health.

Plants / animals Type of food

Cabbage, mustard vegetable

Ginseng, quinine Medicine

Oil palm tree Margarine, oil

Fish Meat, oil

Chicken Meat, egg

Goat Meat, milk

clothesWe need clothes to keep warm. Clothes protect us from cool weather & rain.

Plants / animals Type of clothes

Cotton Shirts

Latex Shoes, gloves

Pandanus (screw pine)

Hat

Wool Thick clothing

Silkworms Blouses, shirts

Crocodile skin Shoes, bags, belts

Building material

We need building materials for building & making tools & furniture

Plants / animals building materials

product

Rattan Furniture, baskets

Nipah palm Roofs

Teak Houses,bridges,furniture

Bamboo Rafts

Buffalo & camel skin Tents

FUEL

Plants / animals Fuel

Mangrove trees Firewood, charcoal

Plant remains Coal

Palm oil Oil for lamp

Plant & animal remains Petrol, kerosene, diesel, natural gas

whale Lamp oil

We need fuel for cooking, to keep warm, supply light, run our vehicles & work machinery

ELEMENTS, COMPOUNDS & MIXTURE

M eta l N on -m eta l

E lem en t C om p ou n d M ixtu re

M atte r

ElementsAn elements is the simplest form of matter.

It cannot be broken down into two or more simpler substances by chemical or physical means.

An element can be made up of one type of similar atoms. A group of similar atoms is known as a molecule.

Copper molecule

Oxygen molecule

Oxygen is the element that is found the most on earth.

Elements can be classified as metals & non-metals.

All metallic elements are solid states at room temperature,except mercury.

Solid state- aluminium, tin, silver, potassium, cooper, iron.

Liquid state- mercury

non-metallic elements exist in solid, liquid & gaseous states at room temperature.

Carbon, iodine & sulphur – solid

Bromine – liquid

Oxygen, Chlorine, Hydrogen & Nitrogen - gas

Differences in physical characteristics of metal & non-metal

Metal Differences Non-metal

Shiny Surface property Dull

Malleable Malleability Not malleable

Ductile Ductility Not ductile

High melting point Ability to melt Low melting point

Good conductor Conductivity of heat

Poor conductor

Good conductor Conductivity of electricity

Poor conductor ( except carbon &

silicon)

Properties of metals and their uses

Metals Physical properties Uses

Copper •Good conductor of electricity & heat•Strong & does not corrode easily

•Making electrical wires and cooking utensil

Aluminium •Good conductor of heat•Ductile & malleable•Low density (light) & strong

•Making cooking utensil•Making cables, aluminium foil, construction frames & aircraft

Metals Physical properties Uses

Iron •hard, strong, does not melt easily

•Making steel, machinery, bridges, , machines & engine

Mercury •Shiny liquid & good conductor of heat

•Liquid in thermometer

Gold / silver

•shiny, ductile, malleable & does not corrode

* Making jewellery & ornaments

Uses of non-metals

Non-metal Uses

Carbon •Charcoal is a type of carbon that can be used as fuel•Black lead is made of carbon

Sulphur •Sulphuric acid ( a chemical) is produced using sulphur•Sulphur is an important component in fertilisers

Non-metal Uses

Chlorine * Chlorine is added to drinking water & swimming pools as a steriliser to kill microorganisms.

Helium *Light & not explosive , suitable fill in balloons and lamp advertising

Diamond * hard, cutting glass & stones, in jewellery

Compounds

A compound is formed when two or more different elements combine chemically.

Compounds are formed through chemical reactions.

The properties of a compound are different from those of their constituent elements

A compound becomes an entirely new substance.

Examples of compounds are iron rust (iron oxide), magnesium oxide, carbon dioxide and copper sulphate.

The smallest possible particle of a compound is a molecule.

A compound may be separated into its elements by using electricity ( a chemical process). The process in which this occurs is called electrolysis.

Water

1 atom oxygen & 2 atoms hydrogen

Hydrogen chloride

1 atom hydrogen & 1 atom chlorine

Ammonia

1 atom nitrogen & 3 atoms hydrogen

Methane

1 atom carbon & 4 atoms hydrogen

Common compounds

Compound Element present State at room temperature

Carbon dioxide Carbon, oxygen Gaseous

Ammonia Nitrogen, hydrogen Gaseous

Water Hydrogen, oxygen Liquid

Sulphuric acid Hydrogen, sulphur, oxygen Liquid

Rust Iron ,oxygen Solid

Sand Silicon, oxygen Solid

Mixture

A mixture is a substance that consists of two or more substances which are not joined together chemically.

There is no chemical reaction in the formation of mixtures.

A mixture of metals is known as an alloy.

The constituents of a mixture keep their own original properties which are unchanged.

A mixture may consist of elements, compounds or both.

Mixture

+ =

Element P Element Q Mixture P and Q

Differences between compounds and mixture

Compound Differences Mixture

Through chemical reaction

Formation Through physical methods

Heat is absorbed or released

Energy change

No heat change

New substance formed

Formation of new substance

No new substance

New properties are formed

Properties of components

Properties of components

remain

Ratio of components is

fixed

Composition Ratio of components is

not fixed

Chemical processes

Separation methods

Physical processes

Separation of mixture

Components of a mixture can be separated using these physical methods;

Using a magnet

Filtration

Distillation

Evaporation Using separating funnel

Sieving Sublimation

ELEMENT / UNSUR

+ =1 ATOM 1 ATOM MOLECULE

Sangat kecil dan tidak boleh dipecahkan lagi kepada saiz yang lebih kecil.

Terdapat dalam 2 kategori : logam dan bukan logam

Compounds / sebatian

+ =1 ATOM BIRU 2 ATOM MERAH COMPOUND

+ =

2 atau lebih atom yang berlainan jenis bergabung secara kimia dan membentuk bahan baru.

Dapat diasingkan balik kepada bentuk asal secara elektrolisis sahaja.

Elektrolisis proses

Mixture / campuran

+ =2 atau lebih atom yang berlainan jenis bergabung secara fizikal dan tidak membentuk bahan baru.

Dapat diasingkan balik kepada bentuk asal secara proses fizikal.

Ia mempuyai sifat asal bahan tersebut.

Preservation and conservation of resources on earth

The resources on Earth must be preserved and conserved from change and destruction.

The way to preserve and conserve earth”s resources :

# Recycling resources – old mining land can be used for housing and agriculture

# controlling air pollution – avoid open burning of rubbish

# Recycling substances – glass, tin, plastic containers & old newspaper

# Use of substitutes – replacing the use of substances like metals with other materials like plastic

# Keeping forest reserves – using up unfinished exercise books as note books and recycling paper are ways to reduce the felling of trees

# Conserving water – not wasting water to prevent water shortage

# using resources efficiently and intelligently

• I hope all of you understand and please read all your note and other references book for more information.

• From : your science teacher “ Pn. Ainun Zuraiha bt. Alias.