CHAPTER 4THE VARIETY OF RESOURCES ON

EARTH

Resources on Earth

Living things

Animals

Plants

Non living things

Air

Water

Fossil fuels

Natural Gas

Petroleum

Coal

Soil

4.1 Natural Resources on Earth

4.2 Understanding Element, Compound and Mixture

Matter

Element

Metal

Nonmetal

Compound Mixture

Video 1: Elements http://www.youtube.com/watch?v=d0zION8xjbM

Element

• Element: a substance that consists one type of atom only.

• It is the simplest matter and cannot be separated by any chemical or physical method.

Atom Molecule

Classification of ElementElement

Metal- In solid form except for mercury (liquid)

-Eg: calcium, copper, gold, lead

Non metal-Exist in all states

(solid, liquid and gas) at room

temperature.-Eg: sulphur, carbon,

bromine, oxygen

Surface

Melting and boiling point

Electric Conductivity

Malleability

Ductility

Heat Conductivity

Shiny

Malleable

Ductile

Good

Good

High

Dull

Not malleable

Brittle

Weak

Do not conduct, except Carbon

Low

Met

als

Non M

etals

Density High Low

Surface

• The surface of metals are usually shiny when polished compared to nonmetals.

Malleability

• Malleability is the ability of a metal to be hammered, rolled, or pressed into various shapes without rupture or fracture.

Malleability

Ductility

• Ductility is the ability of a metal to be bent or stretched permanently without rupture or fracture.

• Metals that lack ductility will crack or break before bending.

Ductility

Nonmetal- silicon Metal- aluminium

Heat Conductivity

• The ability to transfer heat.• Which material is easier to get hot? Metal or

nonmetal material?

Electric conductivity

• The ability of transferring electricity.

Melting and boiling pointDensity

• Most metals are solid (except for mercury), therefore it requires more heat to melt them.

• Since metals are mostly solids, their mass are higher, thus their densities are all high.

Properties of metals

Video 2: http://www.youtube.com/watch?v=anRdgl4D5KI

Compound • A compound is a substance that contains two

or more atoms chemically combined together. • The components in compound can only be

separated through chemical reactions such as electrolysis or heating.

Mixture • A mixture is a combination of two or more

substances that have been mixed physically; for example by stirring.

• A mixture may consists of elements, compounds or both.

Video 3: http://www.youtube.com/watch?v=cL6I1O1YHH0

The differences between compound & mixture

Formation

Separation

Formation of new substance

Properties of components

Conversion of energy

Chemically formed

New substance is formed

New properties

Heat energy is released

Can be separated chemically

Physically mixed

No new substance is formed

Retain its original properties

Heat energy is not released

Can be separated physically

Compound Mixture

Identification of components

Components that make up compound cannot be

identified

Components of mixture can be identified easily

Electrolysis of Copper (II) Sulphate: Separating a compound

Video 4: http://www.youtube.com/watch?v=Q62UfP-ZADY

When sugar is heated, it will be

broken into carbon and water

Examples of mixtures

Separation of mixture: Physical methods

Filtration: to separate insoluble

solids

Evaporation: to separate dissolved solid particles from

its solvent

Distillation: to separate a solvent

from a liquid or solid-liquid mixture.

Using magnet: to separate

substances which are attracted to a

magnet from nonmagnetic substances.

Sieving: to separate mixture

of solid substances with different sizes.

Extraction: to separate liquid substances that do not mix well

and with different densities

Chromatography: to separate coloured components in a mixture

4.3 Appreciating The Importance Of The Variety OfEarth’s Resources To Man.

OxygenBreathing, cell respiratin, combustion, burning

Carbon dioxideTo put out fire, for photosynthesis

SoilHabitat for many types of living things

Minerals Soil contains minerals and water which is vital for growing of plants

Fossil fuelsTo provide energy for household use, factories and power stations to generate electricity.

Water Regulates body temperature, controls the concentration of blood

Living thingsAs food, medicine, fibre, building materials, and so on.

Conservation And Preservation

• Conservation: involves the intelligent use and care of our resources.

• Preservation: the act of keeping the resources in their original state.