CBSE Class IX Chemistry Natural resources
CBSE Class IX Chemistry Natural resources
Published on: Mar 3, 2016
Transcripts - CBSE Class IX Chemistry Natural resources
The resources we get from nature are
called as natural resources. These are
equally important for the survival of human
beings. There are two main natural resources :-
(iii) Others are :-
Coal, fossil fuels, rock and mineral resources
Water, oceans, lakes, groundwater and rivers
Some resources under water and air are :-
Water – water cycle, rain etc.
Air – different gases and their cycles(oxygen, nitrogen)
Air is nothing but it is just the part of Earth's atmosphere that
We humans breathe (oxygen).
Water is a chemical substance with the chemical formula H2O.
Its molecule contains one oxygen and two hydrogen atoms
connected by covalent bonds. Water is a liquid at ambient
conditions, but it often co-exists on Earth with its solid state,
ice, and gaseous state, water vapor or steam.
Plants are living organisms belonging to the kingdom
Plantae. The scientific study of plants, known as botany,
has identified about 350,000 extant Species of plants,
defined as seed plants, bryophytes, ferns and fern allies.
As of 2004, some 287,655 species had been identified, of
which 258,650 are flowering and 18,000 bryophytes.
Green plants obtain most of their energy from sunlight
by a process called photosynthesis.
Fossil fuels are fuels formed by natural resources such as an aerobic
decomposition of buried dead organisms. The age of the organisms and their resulting
fossil fuels is typically millions of years, and sometimes exceeds 650 million years. The
fossil fuels include coal, petroleum, and natural gas which contain high percentages of
In geology, rock or stone is a naturally occurring solid aggregate of
Minerals and/or mineraloids. The Earth's outer solid layer, the
lithosphere, is made of rock. In general rocks are of three types, namely,
igneous, sedimentary, and metamorphic. The scientific study of rocks
is called petrology, and petrology is an essential component of geology.
A solid inorganic substance of natural occurrence and obtained by mining. Mineral
resources are those economic mineral concentrations that have undergone
enough scrutiny to quantify their contained metal to a certain degree.
None of these resources are ore because the economics of the mineral
deposit may not have been fully evaluated.
Forestry is the art and science of managing forests, tree
plantations, and related natural resources. The main
goal of forestry is to create and implement systems that
allow forests to continue a sustainable continuation of
environmental supplies and services. The challenge of forestry is to create
Systems that are socially accepted while sustaining the resource and any other
resources that might be affected.
Soil is a natural body consisting of layers (soil horizons) of mineral
constituents of variable thicknesses, which differ from the parent materials in
their morphological, physical, chemical, and mineralogical characteristics. It
is composed of particles of broken rock that have been altered by chemical
and environmental processes that include weathering and erosion. Soil differs
from its parent rock due to interactions between the
lithosphere, hydrosphere, atmosphere, and the
biosphere. It is a mixture of mineral and organic
constituents that are in solid, gaseous and aqueous
An ocean is a major body of saline water, and a principal
component of the hydrosphere. Approximately
71% of the Earth's surface is covered by
ocean, a continuous body of water that is
Customarily divided into several principal
ocean and smaller seas.
A lake is a body of relatively still fresh or salt water of
considerable size, localized in a basin that is
surrounded by land. Lakes are inland and
not part of the ocean, and are larger and
deeper than ponds. Lakes can be contrasted
with rivers or streams, which are usually
flowing. However most lakes are fed and
drained by rivers and streams.
Ground water is the water found below the
surface of earth or below the soil. It is widely
used by farmers for irrigating their fields. But
erratic rainfall and overuse of ground water is
resulting in decreasing of ground water level.
A river is a natural watercourse, usually freshwater, flowing toward
an ocean, a lake, a sea, or another river. In a few cases, a river simply
flows into the ground or dries up completely before reaching another
body of water. Small rivers may also be called by several other names,
including stream, creek, brook, rivulet,
tributary and rill; there is no general rule that
defines what can be called a river, although in
some countries or communities a stream may
be defined by its size.
Air pollution is the introduction of chemicals,
particulate matter, or biological materials that cause harm
Or discomfort to humans or other living organisms,
or damages the natural environment into the atmosphere.
The atmosphere is a complex dynamic natural gaseous
system that is essential to support life on planet Earth.
Stratospheric ozone depletion due to air pollution has long
been recognized as a threat to human health as well as to
the Earth's ecosystems.
Indoor air pollution and urban air quality are listed
as two of the world's worst pollution problems in the
2008 Blacksmith Institute World's Worst Polluted
Wind is the flow of gases on a large
scale. On Earth, wind consists of the
bulk movement of air. In outer
space, solar wind is the movement of
gases or charged particles from the
sun through space, while planetary
wind is the out-gassing of light
chemical elements from a planet's
atmosphere into space. Winds are
commonly classified by their spatial
scale, their speed, the types of forces
that cause them, the regions in
which they occur, and their effect.
The strongest observed winds on a
planet in our solar system occur on
Neptune and Saturn.
In meteorology, winds are often referred to
according to their strength, and the direction the
wind is blowing from. Short bursts of high speed
wind are termed gusts. Strong winds of intermediate
duration (around one minute) are termed squalls.
Long-duration winds have various names associated
with their average strength, such as breeze, gale,
storm, hurricane, and typhoon. Wind occurs on a
range of scales, from thunderstorm flows lasting tens
of minutes, to local breezes generated by heating of
land surfaces and lasting a few hours, to global
winds resulting from the difference in absorption of
solar energy between the climate zones on Earth. The
two main causes of large scale atmospheric
circulation are the differential heating between the
equator and the poles, and the rotation of the planet
(Coriolis effect). Within the tropics, thermal low
circulations over terrain and high plateaus can Drive
monsoon circulations. In coastal areas the sea
breeze/land breeze cycle can define local winds; in
areas that have variable terrain, mountain and valley
breezes can dominate local winds.
The atmosphere keeps the average temperature of the
Earth fairly steady during the day and even during the
course of the whole year. The atmosphere prevents the
sudden increase in temperature during the daylight hours.
And during the night, it slows down the escape of heat
into outer space.
The ozone layer is a layer in Earth's atmosphere which
Contains relatively high concentrations of ozone (O3).
This layer absorbs 97–99% of the sun's high frequency
ultraviolet light, which is potentially damaging to life
on earth. It is mainly located in the lower portion of the
stratosphere from approximately 13 km to 40 km above
Earth, though the thickness varies seasonally and
geographically. The ozone layer was discovered in 1913
by the French physicists Charles Fabry and Henri Buisson.
In ecology and Earth science, a biogeochemical cycles
cycle or nutrient cycle is a pathway by which a chemical
element or molecule moves through both biotic (biosphere) and
abiotic lithosphere, atmosphere, and hydrosphere)
compartments of Earth. In effect, the element is recycled,
although in some cycles there may be places (called reservoirs)
where the element is accumulated or held for a long period of
time (such as an ocean or lake for water). Water, for example, is
through. the water
Nitrogen is required for the manufacturing of
all amino acids and nucleic acids; however, the
average organism can not use atmospheric nitrogen
for these tasks and as a result is dependent on the
nitrogen cycle as a source for its usable nitrogen. The nitrogen cycle begins
with nitrogen stored in the atmosphere as N2 or nitrogen stored in the soil as
ammonium (NH4+), ammonia (NH3), nitrite (NO2−), or nitrate (NO3−). Nitrogen is
assimilated into living organisms through three stages: nitrogen fixation, nitrification,
and plant metabolism. Nitrogen fixation is a process which occurs in prokaryotes in
which N2 is converted to (NH4+). Atmospheric nitrogen can also undergo nitrogen
fixation by lighting and UV radiation and become NO3-. Following nitrogen fixation,
nitrification occurs. During nitrification, ammonia is converted into nitrite, and nitrite
is converted into nitrate. Nitrification occurs in various bacteria. In the final stage,
plants absorb ammonia and nitrate and incorporate it into their metabolic pathways.
Once the nitrogen has entered the plant metabolic pathway, it may be transferred to
animals when the plant is eaten. Nitrogen is released back into the cycle when
denitrifying bacteria convert NO3- into N2 in the process of denitrification, when
detrivorous bacteria convert organic compounds back into ammonia in the process of
ammonification, or when animals excrete ammonia, urea, or uric acid.
The Oxygen cycle is the biogeochemical
cycle that describes the movement of oxygen
within its three main reservoirs: the
atmosphere (air), the total content of biological matter within the
biosphere (the global sum of all ecosystems), and the lithosphere
(Earth's crust). Failures in the oxygen cycle within the
hydrosphere (the combined mass of water found on, under, and
over the surface of a planet) can result in the development of
hypoxic zones. The main driving factor of the oxygen cycle is
photosynthesis, which is responsible for the modern Earth's
atmosphere and life.
Carbon is continuously cycled between the oceans, land, and the
atmosphere. The atmospheric carbon is primarily carbon dioxide. Carbon, on
land, occurs primarily in living biota and decaying organic matter.
Dissolved carbon dioxide and small organisms like plankton that store
carbon dioxide are major sources in the ocean. Carbon is measured in
Gigatons, with the deep ocean containing almost 40,000 Gt, compared to
about 2,000 Gt on land and 750 Gt in the atmosphere.
Carbon dioxide, a known "greenhouse gas", traps
some of the radiation in the atmosphere that would be
lost in space. This causes the atmosphere to be
warmer than it would naturally be. Since pre –
industrial times man-made emissions have increased
the amount of carbon dioxide in the atmosphere by
about 30%. The increase in carbon dioxide causing
global warming is important for us to understand so
we can predict future implications concerning our planet.
The greenhouse effect is a process by which radiative energy
leaving a planetary surface is absorbed by some atmospheric gases,
called greenhouse gases. They transfer this energy to other components
of the atmosphere, and it is re-radiated in all directions, including back
down towards the surface. This transfers energy to the surface and
lower atmosphere, so the temperature there is higher than it would be
if direct heating by solar radiation were the only warming mechanism.
This mechanism is fundamentally different from that of an actual
greenhouse, which works by isolating
warm air inside the structure so that heat is
not lost by convection.
The greenhouse effect was discovered
by Joseph Fourier in 1824, first reliably
experimented on by John Tyndall in 1858,
and first reported quantitatively by Svante
Arrhenius in 1896.
There are three main mineral riches of the soil. These are :-
The sun :- The sun heats up rocks during the day so that
they expand. At night these rocks cool down and contract. Since
all parts all parts of the rock do not expand and contract at the
same rate, this results in the formation of cracks and ultimately the huge rocks
Break up into smaller pieces.
Water :- Water helps in the formation of soil in two
ways. First, water could get into the cracks in the rocks
formed due to uneven heating by the Sun. if this
water later freezes, it would cause the cracks to widen.
Second, Flowing water wears away even hard rock
over long periods of time. Fast Flowing water often
carries big and small particles of rock downstream. The water then takes these
particles along with it and deposits it further down its path. Soil is thus found in
places far away from its parent- rock.
Wind :- strong winds erode the rocks. Wind carries sand
from one place to other
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation
such as snow, hail and sleet. Rain requires the presence of a thick layer of the
atmosphere to have temperatures above the melting point of water near and
above the Earth's surface. On Earth, it is the condensation of atmospheric water
vapour into drops of water heavy enough to fall, often making it to the surface.
Two processes, possibly acting together, can lead to air becoming saturated
leading to rainfall: cooling the air or adding water vapor to the air. Virga is
precipitation that begins falling to the earth but evaporates before reaching the
surface; it is one of the ways air can become saturated. Precipitation forms via
collision with other rain drops or ice crystals within a cloud. Rain drops range in
size from oblate, pancake-like shapes for larger drops, to small spheres for smaller
The water cycle, also known as the hydrologic cycle or H2O cycle,
describes the continuous movement of water on, above and below the
surface of the Earth. Water can change states among liquid, vapour,
and ice at various places in the water cycle. Although the balance of
water on Earth remains fairly constant over time, individual water molecules
can come and go. The water moves from one reservoir to another, such as from
river to ocean, or from the ocean to the atmosphere, by the physical processes
of evaporation, condensation, precipitation, infiltration, runoff, and
subsurface flow. In so doing, the water goes through different phases: liquid,
solid, and gas.
The hydrologic cycle also involves the
exchange of heat energy, which leads to
temperature changes. For instance, in
the process of evaporation, water takes
up energy from the surroundings and
cools the environment. Conversely,
in the process of condensation, water releases
energy to its surroundings, warming the
Water pollution is a major problem in the global context. It has been suggested
that it is the leading worldwide cause of deaths and diseases, and that it accounts for
the deaths of more than 14,000 people daily. An estimated 700 million Indians have no
access to a proper toilet, and 1,000 Indian children die of diarrheal sickness every
day. Some 90% of China's cities suffer
from some degree of water pollution and
nearly 500 million people lack access to safe
drinking water. In addition to the acute
problems of water pollution in developing
countries, industrialized countries continue
to struggle with pollution problems as well.
In the most recent national report on water quality in the United States, 45
percent of assessed stream miles, 47 percent of assessed lake acres, and 32 percent of
assessed bay and estuarine square miles were classified as polluted.
Water is typically referred to as polluted when it is impaired by anthropogenic
contaminants and either does not support a human use, like serving as drinking
water, and/or undergoes a marked shift in its ability to support its constituent biotic
communities, such as fish. Natural phenomena such as volcanoes, algae, blooms,
storms, and earthquakes also cause major changes in water quality and the ecological
status of water.
Natural resources are resources which we get
from nature and which are formed without any
human interference. Like coal, petroleum etc.
these were formed years ago by natural processes.
These resources are very important for survival of
NATURAL RESOURCES ARE VERY IMPORTANT