Science Form 1 Chapter 4

CHAPTER 4

The Variety Resources On Earth 4.1

The different resources on earth List the resources on Earth needed to sustain life List resources on Earth used in everyday life

Since the beginning of life on Earth, every living thing depends on Earth’s resources such as energy, plants, animals, air, water, soil and other living things to stay alive. Imagine what will happen to us if Earth is without the essential resources below.

Air , Living things, water, energy, soil

What is Matter? Since the beginning of life on Earth, every living thing depends on Earth’s resources such as energy, plants, animals, air, water, soil and other living things to stay alive. Imagine what will happen to us if Earth is without the essential resources below. Discuss what your life would be like if Earth’s resources are lost.

All resources on Earth are classified as matter except energy. Why? What is matter made up of?

Various resources Air Is needed by all living things to survive. Air is a mixture of gases. It consists of : Nitrogen Oxygen Carbon dioxide Water vapour Inert gases Dust and microorganism The layer surrounding the earth is called ATMOSPHERE Water • Covers a total of about three quarted of the Earth’s surface

Various resources Sources of water include: Rivers Lakes Oceans Seas Rainfall Groundwater All living things need water to survive. 70% of the human body is water.

Soil Is the habitat for many types of organisms

Various resources Soil provides support for plants and ensure proper growth for plants There are various types of flora and fauna on Earth. These flora and fauna are natural resources that sustain life. They provide us food, clothes and building materials.

Minerals Are inorganic substances found naturally on land and in seas. Examples: - iron - Silver - lead - gold Minerals are required by our body to ensure proper functioning of our systems.

Various resources Minerals are also required by plants for healthy growth.

Fossil Fuels Formed from the remains of animals and plants that died millions of years ago Fossil fuels include petroleum natural gas and coal Petroleum is a hydrocarbon that can be separated into different components by fractional distillation

Living Things The living things consists of plants (flora) and animals (fauna). Living things provide us with food, clothes, fuels, building materials and medicine

CHAPTER 4

The Variety Resources On Earth 4.2

What are elements, compounds, mixtures State what elements, compounds and mixtures are Give examples of elements, compounds, mixtures State differences of elements, compounds, mixtures Carry out activities to see the differences of metal and non metal Classifies elements as metal and non-metal Give examples of metals and non-metals Carry out activities to separate the components of mixture

Elements Matter on Earth is made up of elements. An element is a substance that cannot be broken down into two or more simpler substances by any known method. More than one hundred elements have been discovered or synthesized by scientists. Most of the elements occur naturally while the rest are manmade. Hydrogen and helium are the most abundant elements in our universe. Oxygen and silicon are the most abundant elements in the Earth’s crust.

Most elements are solids at room temperature except for bromine and mercury which are in liquid form. 11 elements are gases including chlorine, fluorine, oxygen and helium.

Element Molecule of element

An element is made up of 1 type of molecule only

Elements All metal elements are solids at ordinary room temperature except mercury To find out whether an element is metal or non-metal, we have to identify and compare the properties of the element with those of metals or non-metals. The table below shows the general propeties of metals and non-metals

Metal Shiny Good electric conductor Good heat conductor High melting points High density

Non-metal Appearance Electric conductivity Heat conductivity Melting points Density

Dull / not shiny Poor (except graphite) Poor heat conductor Low melting points Low density

Hard

Solids

Soft

Ductile / easily molded

Ductile

Not ductile / snap easily

Malleable (easily shaped)

malleability

Brittle (easily break when beaten)

Uses of Metal

Uses of Non-Metal

Compounds A compound is a substance formed by the chemical combination of two or more elements. Every compound is represented by a chemical symbol.

Example Water is a compound because it is made up of two chemically combined elements, which are hydrogen and oxygen. Have you seen the symbol

H2O before? These particles combined chemically in a fixed proportion. Compound can only be separated by chemical methods such as electrolysis. Some examples of compounds are common salt, water, sand and carbon dioxide. Example

Compound Molecule of element Element X

Combined together chemically

Compound Element Y

Examples of Compound Molecule of element Oxygen Atom

Water is made up of two types of elements: Oxygen and Hydrogen

Hydrogen Atoms

Ammonia is made up of two types of elements: Nitrogen and hydrogen Hydrogen Atoms

Nitrogen Atom

Mixtures

Mixtures are substances that are made up of two or more types of particles which combine physically. These particles do not combined chemically and they are mixed in any proportion. Some of the examples of mixtures are blood, sea water, air and soil The components of mixture can be separated by physical methods such as evaporation, filtration, using separating funnel and using a magnet.

Mixture Element X

Compound X

Element Y Compound Y

Element Z

Mixture of elements

Mixture of compounds

Element Y Element X Compound

Mixture of elements and compound

Comparison of compounds and mixtures Compound

Difference

Mixture

Formed using chemical methods

Method of formation

Formed using physical methods

New substances formed

Formation of new substances

No new substances formed

Heat is absorbed or released during formation

Energy changes

No heat is absorbed or released during formation

Ratio of components is fixed

Composition of components

Ratio of components is not fixed

New properties are formed

Properties of components

Properties of components remain the same

Components can only be separated using chemical methods

Separation of components

Components can be easily separated using physical methods

CHAPTER 4

The Variety Resources On Earth 4.3

The importance of the variety of Earth’s resources to Man

Explain the importance of the variety of Earth’s resources to man State the meaning of preservation and conservation of resources on Earth State the importance of preservation and conservation of resources on Earth Practice reusing and recycling of materials

All living and non-living things on Earth are interlinked.You can perceive things on Earth as a giant spider web.The threads of the web are the relationships among the plants, animals, soil, water, temperature, light and other living and non-living things. Do you think the basic needs of life are also related to the Earth’s resources?

Water For drinking, cooking, washing and bathing. About 70% of the human body weight is made up of water. Dissolves and transports food and oxygen to all parts of the body. For generating electricity. For recreational activities.

AIR Oxygen is needed for respiration and combustion Carbon dioxide is needed for photosynthesis

Resources On Earth

Fossil Fuels A very important source of energy. For generating electricity Fuel

Minerals Needed by man, animals and plants for healthy growth. Metals are used in the construction of building and bridges

Soil Agriculture Mining Construction of buildings Making ceramics, glass, cement and bricks Habitat for many living things

Preservation and Conservation Preservation Is the effort to maintain natural resources in their original state

Conservation Is the careful use and management of natural resources so as to minimize loss, wastage and damage Preservation and conservation of natural resources are very important to prevent:

a) Destruction to the natural environment b) The extinction of animals and plants c) The loss of economic resources d) Pollution of air, water and soil e) Health problems f) Natural disasters

Effects of pollution 1. Air pollution causes green house effect and acid rain 2. Water pollution reduces sources of clean water and threatens the habitats of aquatic life 3. Soil pollution results in the infertility of the soil and natural habitats of living things being damaged

Ways to reduce pollution on Earth’s resources 1. Recycle waste materials 2. Use recycle papers 3. Practice reforestation 4. Practice selective logging 5. Use unleaded petrol 6. Use biodegradable substances 7. Fix filters to factory chimneys in order to filter poisonous gases

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