Due to their impressive bulk, mountains are often considered to be symbols of permanence. But how long can a mountain really exist, given the steady erosion of its rock and soil? We can figure this out with a little math and a few approximations. The overall problem solving strategy is to estimate the size of a typical mountain, to estimate how much material erodes from it per unit time, and then to divide the size of the mountain by its rate of erosion.

To estimate the volume of a mountain, approximate its shape as a rectangular box. Mountains come in an array of size and shapes, but a box 3 km long, 2 km wide and 5 km high would give us the approximate volume of an average mountain:

Volume = length *width*height
= 3 km* 2 km * 5 km = 30 km3

Expressing this in standard units of meters, we have

Volume = (3000m) * (2000m) * (5000m)
= 3.0 * 1010 m3.

Now estimate how much rock, sand, and gravel are eroded in a typical day. This would vary according to the kinds of rock that are present, the amount of precipitation, and other factors. But an average mountain could have four principal streams, and each one could easily carry a tenth of a cubic meter of material off the mountain per day. This is a conservative estimate-a tenth of a cubic meter is a box about a foot and a half on each side, about the size of a kitchen sink. So the estimated rate of erosion per day would be:

Rate of erosion per day = (0.1 m3/stream-day) * (4 streams)
= 0.4 m3/day

From this, we can calculate the rate of erosion per year:

Rate of erosion per year = (0.4 m3/day)*(365 days/year)
= 146 m3/year

Divide the volume of the mountain by the rate at which it is worn away in a year to find out how long it can last:

Duration of a mountain = (3.0 * 1010 m3)/ (146 m3/year)
= 2.05 * 108 years = 205 million years.

Thus, a typical mountain would exist only about two hundred million years, even given a conservative estimate of the rate of erosion. Compared with the age of the Earth, which is 4.5 billion years, mountains are young features with short lifetimes.

At every moment of the day and night large amount of water vapour are drawn up from the surface of the earth in tiny invisible drops. The water of the seas, lakes and rivers is constantly being evaporated.When we hang out our washing on the line we find after some time that is dry, which means that the water it contained has passed into the air. Incredible amounts of water in the form of vapour are given off by plants as part of their chemical activity in the production of organic substances.

Where does all this water vapour go to?
The answer is into the sky: it rises moment by moment, higher and higher because it is lighter than air. But when it reaches the cold levels of atmosphere the vapour condenses, the drops of water combine and the vapour becomes visible as clouds, which are nothing more than masses of water vapour which have reached a certain stage of condensation. Wind and air currents then take control of the clouds and drive them all in a givem direction, but at this stage the water vapour, although dense, still remains lighter than air, and therefore there is no rainfall.

Rain occurs when there is excessive concentration of vapour due to the action of the wind or to a further fall in temprature which causes the drops of vapour to condense still more to form heavy drops which can no longer be supported by the air. At this point supported by the air. At this point they begin to fall back on to the surface of the Earth in the form of rain.

Among regular winds the commonest are the seas and breezes. These are very light local winds caused by the difference of temprature between land and sea.
During the day the earth warms up more quickly than the sea and therefore the air above it becomes lighter and rises, creating an area of rarefield atmosphere at ground level. The air above the sea, which is colder and therefore more compressed and heavier, is drawn into this sea to blow towards the land, that is a sea breeze.

Towards evening and during the night, on the other hand, the wind changes direction and goes from the land to the sea, that is a land breeze. This happens because the land cools more easily and brings about a similar cooling of the air which now remains warm. This is well known to all fishermen who time their departure by it. Nowadays when boats use engines and are no longer dependent on the wind it is no more than a pleasant feature of coastal areas.

Rain occurs when there is excessive concentration of vapour due to the action of the wind or to a further fall in temprature which causes the drops of vapour to condense still more to form heavy drops which can no longer be supported by the air. At this point supported by the air. At this point they begin to fall back on to the surface of the Earth in the form of rain.

Climate Change is the change in climate over a time period that ranges from decades to centuries. The term refers to both natural and human-induced changes. The term “climate variability” refers to shorter term (years to decades) fluctuations in climate such as those caused by El Niño/Southern Oscillation.

The United Nations Framework Convention on Climate Change defines climate change as: “a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods”. In other words, the FCCC uses the term Climate Change to mean only those changes that are brought about by human activities.

Factors Affecting Global Climate: There are many factors, both natural and of human origin, that determine the climate of the Earth.

Greenhouse Gases A number of minor gases in the atmosphere, although relatively transparent to sunlight, absorb most of the infrared heat energy transmitted by the Earth towards space. This phenomenon has been called the “greenhouse effect” and the absorbing gases that cause it “greenhouse gases”. Important greenhouse gases include: water vapour, carbon dioxide, methane, nitrous oxide, ozone, and halocarbons.

Climate Trends An analysis of temperature records shows that the Earth has warmed an average of 0.5°C over the past 100 years. The warming is real and significant though its intensity has varied from decade to decade, from region to region and from season to season.

The retreat of glaciers since 1850, worldwide and rapid, affects the availability of fresh water for irrigation and domestic use, mountain recreation, animals and plants that depend on glacier-melt, and in the longer term, the level of the oceans. Studied by glaciologists, the temporal coincidence of glacier retreat with the measured increase of atmospheric greenhouse gases is often cited as an evidentiary underpinning of anthropogenic (human-caused) global warming. Mid-latitude mountain ranges such as the Himalayas, Alps, Rocky Mountains, Cascade Range, and the southern Andes, as well as isolated tropical summits such as Mount Kilimanjaro in Africa, are showing some of the largest proportionate glacial loss.

The Little Ice Age was a period from about 1550 to 1850 when the world experienced relatively cooler temperatures compared to the present. Subsequently, until about 1940, glaciers around the world retreated as the climate warmed. Glacial retreat slowed and even reversed, in many cases, between 1950 and 1980 as a slight global cooling occurred. However, since 1980 a significant global warming has led to glacier retreat becoming increasingly rapid and ubiquitous, so much so that some glaciers have disappeared altogether, and the existence of a great number of the remaining glaciers of the world is threatened. In locations such as the Andes of South America and Himalayas in Asia, the demise of glaciers in these regions will have potential impact on water supplies. The retreat of mountain glaciers, notably in western North America, Asia, the Alps, Indonesia and Africa, and tropical and subtropical regions of South America, has been used to provide qualitative evidence for the rise in global temperatures since the late 19th century.The recent substantial retreat and an acceleration of the rate of retreat since 1995 of a number of key outlet glaciers of the Greenland and West Antarctic ice sheets, may foreshadow a rise in sea level, having a potentially dramatic effect on coastal regions worldwide.

Indian mega cities are among the most air polluted cities in the world and paying heavy health and economic price for it.

Urbanization is a global phenomenon experienced by economically advanced as well as developing countries. Rapid population growth, industrialization, urbanization, crowded housing conditions, inadequate civic amenities and solid waste mismanagement in mega cities are adversely affecting the environment. More than one fourth of Indian population is living in cities, out of which nearly one fifth is residing in four mega cities. With the increasing urbanization the transport demand has also increased consequently. Rapid and uncontrolled growth of population and the unplanned growth of mega cities in India have led to increasing slums, vehicular traffic and air pollution. Automobile exhaust is a significant source of air pollution. The mega cities of India are affected by environmental problems, not the least of which is deteriorating air quality. This leads to an increase in the air pollution levels and have adverse effects on the health of people. The air quality guidelines of World Health Organization (WHO) are regularly being exceeded in Indian mega cities. Indian mega cities are among the most air polluted cities in the world and paying heavy health and economic price for it.

Air pollution in mega cities is one of the greatest menaces to the health of people. The considerable magnitude of air pollution pulls up the number of people suffering from respiratory diseases and many a times leading to deaths and serious health hazards. Special efforts should be made for educating the general mass and local leaders about the

adverse effects of large population and vehicular pollution through information, education and communication (IEC) activities. The air pollution should not be a responsibility of government alone but mass and local leaders should be encouraged to make dedicated efforts to eradicate the air pollution problems.

Most organisms are in the top layers of soil, usually in the top 2-3 centimetres. Organisms occur to depths of several kilometres below the soil surface.The types of organisms that occur at this depth are not the same as those close to the surface. The organisms in soil are commonly found close to root surfaces, in living roots, in dead roots, on soil particles, or amongst aggregates of soil particles.

Within the top layers of the soil, the earthworms and other soil fauna are able to travel through most parts of the soil. Fungi extend to cover soil particles and aggregates. They can form a mat of hyphae, which can extend to some centimetres or even metres in the soil. Fungi can also grow into soil aggregates and form a network of hyphae inside the aggregate. Bacteria tend to accumulate inside soil aggregates because they are less likely to be eaten by soil animals such as protozoa and mites in this environment. Bacteria can be carried down further into the soil in water that is percolating downwards.

Soils that are clayey often have many bacteria because these soils have lots of small pores which protect the bacteria. On the other hand, Sandy soils with few aggregates are less suitable habitats for bacteria and fungi unless there is lots of organic matter, because in sands the bacteria have fewer small pores to live in.

The constellations are imaginary lines that poets, farmers and astronomers have made up over the past 6,000 years. The purpose for the constellation is to help us tell which stars are which. On a dark night, we can see about 1000 to 1500 stars. Trying to tell which is which is hard. The constellations help by breaking up the sky into more manageable bits. They are used as mnemonics, or memory aids. In addition, there is a standard way to connect the stars that allow astronomers and others who use charts like this to quickly tell what they are looking at.

A polysaccharide is an organic compound composed of many simple carbon compounds, which are identical to eachother and joined together in a long chain. They are released into the soil by microorganisms and roots. Polysaccharides are long and flexible which make points of contact with many soil particles. In this way they have been associated with the formation of aggregates in soil.

Global warming is increase in the average temperature of the Earth’s surface, lower atmosphere and oceans.

It is caused by increase in concentrations of greenhouse gases such as carbon dioxide, methane and nitrous oxide in the atmosphere having origin in human activities.

Most of the observed increase in global average temperature is attributed to human-induced greenhouse effect.

The atmospheric concentration of carbon dioxide (CO2) and methane (CH4) have increased by 31% and 149% respectively above pre-industrial levels (1750 AD).

The principal sectors contributing to increase in concentration of green house gases include energy, industry, agriculture and forestry. About three-quarters of man-made emissions are due to fossil fuel burning (coal and oil).

Global average air temperature near the Earth’s surface has risen by 0.74 +/- 0.18o C during the past century.

The average global sea level rose at an average rate of 1.8 mm per year between 1961 to 2003 and by 3.1 mm per year between 1993 to 2003.

Maximum temperature is projected to increase by 2-4o C by the 2050s.

Climate models referenced by the Inter-governmental panel on climate Change (IPCC) project that global surface temperature are likely to increase by 1.1 to 6oC by the end of this century.

An increase in global temperature can cause change in the climate which manifest as follows:

Change in the amount and pattern of precipitation.

Increase in frequency and intensity of extreme weather events (cyclones, heat waves, droughts, floods, etc.).

Receding glaciers.

Reduced summer stream flows.

Decline in agriculture yields.

Increased threat to bio-diversity.

Increase in incidence of vector-borne diseases (malaria, dengue, etc.).

Reduce, Reuse, Recycle.

Drive less, Drive smart-Bike, Bus or Walk.

Switch them off-mobile chargers, computers, and other appliances-when not in use.

Be energy efficient- use CFLs instead of incandescent bulbs.

Plant trees-help sequester atmospheric carbon.

Talk about it- create awareness.

Use jute and cloth bags instead of plastic and polythene.

There are two ways in which bacteria are involved in the formation of soil aggregates. Firstly, bacteria produce polysaccharides which make many points of contact with soil particles producing aggregates. Unlike the polysaccharides produced by plant roots, bacterial polysaccharides resist decomposition long enough to be involved in holding soil particles together in aggregates. Secondly, bacteria develop a small electrostatic charge which attracts to the electrostatic charge on clay surfaces, bringing together small aggregates of soil.

Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy caused the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. They don’t just slide smoothly; the rocks catch on each other. The rocks are still pushing against each other, but not moving. After a while, the rocks break because of all the pressure that’s built up. When the rocks break, the earthquake occurs.

Since graphite was discovered in England, it is most likely that the first pencils were made in England, though this is not known for certain. The pencil was further developed by European craftmen. Some time prior to about 1560, graphite was discovered near Borrowdale, England. The usefulness of graphite as a marking substance was quickly realized. Though the exact date is not known for certain, the year 1565 marks the first record of a pencil consisting of a piece of graphite inserted into a wood shaft, making the first ancestor of today’s pencil.

1. Microfauna- ranges size from 20-200µm.
2. Mesofauna- ranges from 200µ m -10mm.
3. Macrofauna- contains the largest soil animal such as earthworm,beetles, termites

Mostly soil animals (and microorganisms) occur in the top 5 cm of soil, although some occur at depth. Soil animals may move to lower soil layers when conditions at the surface very severe. Most soil animals occur in the surface layer because this layer contains the most food (carbon and nutrients) in the form of organic matter and other organisms.

The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as serve as a unit increment to indicate a temperature interval. The Celsius temperature scale was previously known as the centigrade scale. Celsius” is named after the Swedish astronomer Anders Celsius . 0 °C on the Celsius scale is defined as the freezing point of water and 100 °C is defined as the boiling point of water under a pressure of one standard atmosphere.

On the other hand, Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit. In this scale, the freezing point of water is 32 degrees Fahrenheit (°F) and the boiling point 212 °F, placing the boiling and freezing points of water exactly 180 degrees apart.

The Fahrenheit Scale (used in the US), and the Celsius Scale (part of the Metric System, used in India and other Countries) both measure temperature.

• If you freeze water, it measures 0° in Celsius, but 32° in Fahrenheit
• If you boil water, it measures 100° in Celsius, but 212° in Fahrenheit
• The difference between freezing and boiling is 100° in Celsius, but 180° in Fahrenheit.

Barometer is an instrument used to measure atmospheric pressure. It can measure the pressure exerted by the atmosphere by using water, air, or mercury. Pressure tendency can forecast short term changes in the weather .In 1643, Evangelista Torricelli invented the first barometer. Two types of barometers are commonly used in meteorology i.e. the mercury barometer and the aneroid barometer.

Hygrometer is an instrument used for measuring humidity. A simple form of a hygrometer is specifically known as a "psychrometer" and consists of two thermometers, one, which includes a dry bulb and the other which includes a bulb that is kept wet to measure wet-bulb temperature. Evaporation from the wet bulb lowers the temperature, so that the wet-bulb thermometer usually shows a lower temperature than that of the dry-bulb thermometer, which measures dry-bulb temperature. Relative humidity can also be determined by locating the intersection of the wet- and dry-bulb temperatures on a psychrometric chart. One device that uses the wet/dry bulb method is the sling psychrometer, where the thermometers are attached to a handle or length of rope and spun around in the air for a few minutes.

Generally a hygrometer is a pair of red spirit-filled Fahrenheit thermometers, one a dry bulb and the other a wet bulb. The dry bulb thermometer indicates the actual air temperature. At any dry bulb temperature, the wet bulb thermometer reading can vary, depending on the humidity. High humidity results in wet bulb readings close to dry bulb, while low humidity (which speeds water evaporation and causes cooling) results in wet bulb readings noticeably lower that dry bulb.

English inventor Alexander Parkes created the earliest form of plastic in 1855. He mixed pyroxylin, a partially nitrated form of cellulose (cellulose is the major component of plant cell walls), with alcohol and camphor. This produced a hard but flexible transparent material, which he called “Parkesine.” Parkes teamed up with a manufacturer to produce Parkesine; however, they were unable to market it. The material was so strange and new that no one knew how to use it. But later in 1862 he demonstrated the first useable plastic material at great International Exhibition in London.