HISTORY OF THE SEVEN WONDERS OF THE WORLD

Ancient marvels

Antipater, a Greek author living in the Phoenician port of Sidon, lists in one of his poems the most remarkable creations of mankind. They are seven in number: the pyramids of Egypt; the hanging gardens of Babylon; the walls of Babylon; the statue of Zeus at Olympia; the temple of Artemis at Ephesus; the mausoleum of Halicarnassus; the colossus of Rhodes.

His list is the basis of the Seven Wonders of the World, much repeated ever since. Posterity makes one change. It seems a waste for Babylon to have two of the wonders. By about the 8th century AD the walls of Babylon have dropped out, to be replaced by the lighthouse of Alexandria.

The pyramids: c.2500 BC

The three pyramids at Giza, a few miles southwest of Cairo, are by far the earliest of Antipater's seven wonders. The largest of the pyramids, built as the tomb of the pharaoh Khufu (known to the Greeks as Cheops), dates from about 2500 BC. No building in the subsequent 4500 years of history has matched this pyramid for sheer bulk. Nearby, and only slightly smaller, are the pyramids created for Khufu's son and grandson, Khafre and Menkure.

The next in date, among the Seven Wonders, follows after a very long gap of two millennia. It is the hanging gardens of Babylon.


The hanging gardens of Babylon: c.580 BC

No archaeological trace has been found of the hanging gardens, but tradition assigns them to the reign of Nebuchadnezzar in the last years of Babylon's greatness. One story says that he built them to console a wife, homesick in this flat region for the landscape of her childhood, the mountainous country of the Medes. They are 'hanging' gardens in the sense that the plants appear to float in the air, growing on different levels of artificial terraces irrigated from the Euphrates.

The other five wonders are all connected with Greek civilization. They include the most sacred statue of the entire Greek cult, the image of Zeus at Olympia.


The statue of Zeus at Olympia: c.430 BC

The statue of Zeus is the centrepiece of the god's temple at Olympia. About seven times lifesize, it shows him seated on a throne. In one hand he holds the winged figure which to the Greeks symbolizes victory; in the other is a sceptre surmounted by an eagle. The surface of the statue is gold and ivory. In the eyes of the ancient world this is the masterpiece of the great sculptor Phidias, surpassing even his earlier statue of Athena (also of gold and ivory) for the Parthenon in Athens.

The discovery of the workshop of Phidias at Olympia has enabled archaeologists to date the statue of Zeus to the years around 430 BC. Both the temple and the statue are destroyed in the 5th century AD.


The temple of Diana at Ephesus: c.550 BC

The fourth and fifth wonders of the world are in western Turkey. The temple of Artemis (or Diana) at Ephesus is built in about 550 BC by a man whose name has become a byword for wealth - Croesus, king of Lydia. In keeping with his image, the temple is outstandingly large. But it also contains a famous and unusual statue of Artemis.

This Artemis is not the virgin huntress of Greek myth. She is a local fertility goddess, festooned with swathes of pendulous objects variously interpreted as breasts, eggs or even, it has been argued, testicles (the chief priest of Ephesus is always a eunuch). The temple of Artemis is destroyed by Goths in AD 262.


The mausoleum at Halicarnassus: c.350 BC

Halicarnassus in southwest Turkey (the modern Bodrum) is selected as a new capital in the 4th century BC by the ruler of a small kingdom, Caria. The king is Mausolus, who dies in about 353 BC. His spectacular tomb, built for him by his widow Artemisia (she is also his sister), has given the world a new word, 'mausoleum'. It is adorned with sculptures, including a frieze of the battle between the Greeks and the female Amazons.

The temple stands until the 12th century AD, when it is damaged by an earthquake and later plundered for building materials. Many fragments of the sculptures are in the British Museum.


The colossus of Rhodes: 292 BC

A giant bronze statue of Helios the sun god, known subsequently as the colossus of Rhodes, is put up to celebrate the city's survival of a long siege in 305-4 BC. Reinforced with iron and about 30 metres high, it takes some twelve years (292-280 BC) to build and erect beside the harbour. The image of the colossus straddling the harbour entrance is a medieval invention.

Before the end of the 3rd century BC an earthquake snaps the statue off at the knees. It lies, a humbled giant, until AD 653 when the Arabs capture the island. They break it up for scrap and require, it is said, more than 900 camels to cart it away.

The pharos at Alexandria: c.280 BC

The sun god Helios features also in the last of the seven wonders. This is the lighthouse put up on the island of Pharos at Alexandria (as a result pharos becomes the Greek word for any lighthouse). It consists of a three-tier stone tower, said to be more than 120 metres high, which has within it a broad spiral ramp leading up to a platform where fires burn at night. They are reflected out to sea by metal mirrors. Above the fires is a huge statue, of either Alexander or Ptolemy in the guise of Helios.

The lighthouse survives until the 12th century. In the 15th century a fort, still standing today, is built from its ruins.

Bodhgaya

Bodhgaya is the most important Buddhist pilgrimage place in the world. Located in the state of Bihar, it's here that Lord Buddha became enlightened during intense meditation under a Bodhi tree. The exact spot is now marked by the sprawling Mahabodhi Temple complex. It's a very serene and peaceful place. Monks from all over the world can be found sitting at the foot of an enormous carved Buddha statue, reading holy scriptures in deep contemplation. The town is also home to dozens of Buddhist monasteries, maintained by various Buddhist countries.
Getting to Bodhgaya:
Gaya airport, 12 kilometers (7 miles) away, has infrequent direct flights from Kolkata. If you're coming from other major Indian cities, the nearest airport is in Patna, 140 kilometers (87 miles) away. Alternatively, Bodhgaya can be conveniently reached by train. The nearest railway station is Gaya, which is well connected with Patna, Varanasi, New Delhi, Kolkata, Puri, and other places in Bihar.

If you're interested in visiting Bodgaya as part of a pilgrimage to other Buddhist sites in India, Indian Railways operates a special Mahaparinirvan Express Buddhist Tourist Train service.

When to Visit Bodhgaya:
The pilgrimage season starts in Bodhgaya from September, and reaches a peak in January. Ideally, the best time to visit weather wise is between November and February. You should avoid visiting in monsoon season between June and September. The weather gets quite oppressive, followed by heavy rains. Summers, from March to May, are very hot. However, Bodhgaya still attracts a large number of devotees during this time for Buddha Jayanti (Buddha's birthday) celebrations, held in May.
Bodhgaya Attractions:
The elaborately carved Mahabodhi Temple, Buddhism's holiest shrine, is the big attraction in Bodhgaya. The temple was declared a UNESCO World Heritage Site in 2002. It's open from 5 a.m. to 9 p.m. daily, with chanting and meditation held an hour after opening and an hour before closing. The other monasteries, built and maintained by various Buddhist countries, are also fascinating -- particularly the different architecture styles. Opening hours are from 5 a.m. to noon and 2 p.m. to 6 p.m. Bodhgaya also has an Archaeological Museum displaying an interesting array of relics, scriptures, and ancient statues of Buddha.
Bodhgaya Meditation and Buddhism Courses:
You'll find plenty of meditation and Buddhism courses and retreats on offer in Bodhgaya. The Root Institute for Wisdom Culture offers introductory and intermediate meditation and philosophy courses, explained in the Tibetian Mahayana tradition, from October to March. Those interested in Vipassana Meditation can learn it at the Dhamma Bodhi Vipassana Centre. Ten day residential retreats start on the 1st and 16th of every month. Some monasteries also offer various Buddhism courses.
Bodhgaya Festivals:
The biggest festival in Bodhgaya is Buddha Jayanti, held on a full moon in May each year. The festival celebrates Lord Buddha's birthday. Other festivals in Bodhgaya include the annual Buddha Mahotsava, a three day celebration filled with cultural and religious activities. The Kagyu Monlam Chenmo and Nyingma Monlam Chenmo prayer festivals for world peace are held around January-February every year. The Maha Kala puja is conducted at monasteries for several days before the new year, for purification and to remove obstacles.
Bodhgaya Side Trips:
A side trip to Rajgir, where Lord Buddha spent most of his life teaching his disciples, is recommended. It's located 75 kilometers (46 miles) from Bodgaya, and can be reached by bus or taxi. There you'll be able to visit Gridhakuta (also known as Vulture's Peak), where the Buddha used to meditate and preach in the rainy season. You can take the aerial chair lift up to the top, for great views. The hot springs, at the foot of Vaibhara Hill in Rajgir, are believed to have medicinal properties. It's possible to bathe in them, and there are separate areas for men and women.
Bodhgaya Travel Tips:
There are regular power cuts in Bodhgaya, so it's a good idea to carry a flashlight with you. Both vegetarian and non vegetarian food is available in Bodhgaya, and there's a wide range of cuisine from Thai to Continental. The inexpensive Om Restaurant is very popular with tourists and long term mediators. The tented restaurants are also interesting places to eat -- try the Original Pole Pole. Unfortunately, Bihar is India's poorest state, so expect to encounter plenty of beggars around the Mahabodhi Temple.
Bodhgaya Hotels:
A stay in one of Bodgaya's monasteries is a peaceful alternative to a hotel. One of the best options is the well maintained Bhutanese monastery (phone: 0631 2200710), which is extremely quiet and has rooms located in a beautiful garden. It's also possible to also stay at the Root Institute, which is well located near the Mahabodhi Temple. If you'd prefer to stay in a hotel, the Hotel Tathagat International is close to the Mahabodhi Temple, and is characterful and clean. A non air conditioned double costs around $35.

Ajanta and Ellora Caves

Astonishingly carved into hillside rock in the middle of nowhere are the Ajanta and Ellora caves. There are 34 caves at Ellora dating from between the 6th and 11th centuries AD, and 29 caves at Ajanta dating back to between the 2nd century BC and 6th century AD.
The caves at Ajanta are all Buddhist, while the caves at Ellora are a mixture of Buddhist, Hindu and Jain.

Ajanta and Ellora Caves Location:

The caves are in northern Maharastra, around 400 kilometers (250 miles) from Mumbai.
Getting to the Ajanta and Ellora Caves:
The closest railway stations are in Aurangabad for the Ellora caves (45 minutes away) and Jalgaon for the Ajanta caves (1.5 hours away). There’s also an airport in Aurangabad. It’s possible to hire a car and drive between the two cave sites. Traveling time is around 2 hours.

Ajanta and Ellora Caves Opening Hours:

9am until sunset (around 5.30 p.m.). The Ajanta caves are closed on Mondays, and the Ellora caves are closed on Tuesdays. Both caves are open on national holidays. However, try to avoid visiting then as the crowds can be maddening and you won't have a peaceful experience.

Ajanta and Ellora Caves Cost:

Admission for foreigners is $US10 for the Ajanta caves. The Ellora caves are free to enter except for the magnificent open air Kailasa temple which charges $US 5. Children younger than 15 years are free at both places.
Ajanta and Ellora Festivals:
The four day Ellora Ajanta Festival is held at Soneri Mahal (Golden Palace), an historic 17th century architectural marvel in Aurangabad near Ellora, in the last week of November each year. The festival features some of the most distinguished singers and dancers of India.

Ajanta and Ellora Caves Travel Tips:

The most incredible thing about these caves is that they were crafted by hand, with only a hammer and chisel. While the Ajanta caves are rich in paintings and sculpture, the Ellora caves are renowned for their extraordinary architecture. You can get an excellent view and perspective of inside the Kailasa temple by climbing up the hill around it. Its immense size covers twice the area of the Pantheon in Athens and is one and a half times as high. Bring a torch with you to the Ajanta caves as many of them are quite dark and lighting is poor. The best time to visit is from November to March when it's cooler and dry.

Ajanta and Ellora Hotels:

The Hotel Kailas is located right opposite the Ellora caves. It's a relaxing, tranquil place with stone walls and a scenic landscape. Rates are 900 rupees ($20) for a hostel room, 1500 rupees ($35) for a cottage, and 2000 rupees ($50) for a cottage facing the caves. The hotel has plenty of amenities for guests including a restaurant, internet access, a library and games. You can also go paragliding. Quality accommodations at Ajanta are limited so if you need to stay in the area, it's best to head to the Maharastra Tourism Development Corporation's Holiday Resort in nearby Fardapur. Phone: 02438-244230.

Khajuraho Temples

If you want proof that the Kama Sutra originated in India, Khajuraho is the place to see. Erotica abounds here with over 20 temples devoted to sexuality and sex. These sandstone temples, which date back to the 10th and 11th century, are the only ones remaining out of 85 temples constructed during this time.
There are 3 groups of temples -- Western, Eastern, and Southern. The main temples are in the Western group, which features the magnificent Kandariya Mahadeo Temple. The Eastern Group contains a number of exquisitely sculptured Jain temples. There are only two temples in the Southern group.

Khajuraho Location:
Khajuraho is in northern Madhya Pradesh, approximately 620 kilometers (385 miles) south east of Delhi.
Getting to Khajuraho:
Khajuraho is most easily reached by flight, or alternatively the new Khajuraho-Jhansi Link Express train service. The daily service covers the distance between Khajuraho and Jhansi in around four and half hours. Train 229A leaves Jhansi daily at 7.25 a.m. and arrives in Khajuraho at 12.10 p.m. Coming back, train 230A departs from Khajuraho at 12.30 p.m. and reaches Jhansi at 5 p.m. Avoid traveling to Khajuraho by road if possible. It's a very bumpy five to six hour drive from Jhansi. The bus can be particularly arduous, so hiring a car is a better option under the circumstances.
Khajuraho Opening Times:
The temples are open from sunrise until just before sunset.
Khajuraho Cost:
There is an admission cost of $US 5 for the western group of temples. The others are free. Children younger than 15 years are also free.
Khajuraho Festivals:
A week long classical dance festival is held in Khajuraho at the Chitragupta Temple complex each year, in late February/early March. The festival attracts performers and dance groups from all over India. It offers a captivating way of seeing the various classical styles of Indian dance, including Kathak, Bharat Natyam, Odissi, Kuchipudi, Manipuri and Kathakali. A large arts and crafts fair is also held during the festival.
Khajuraho Travel Tips:
Although Khajuraho is a little out of the way, don’t decide to give it a miss on this basis. No where else will you find such unique temples with meticulously detailed carvings. The temples are best known for their erotic sculptures. However, more than that, they show a celebration of love, life and worship. They also provide an uninhibited peek into ancient Hindu faith and Tantric practices. If you need another reason to visit, only half an hour away is the added attraction of the dense, wildlife filled jungle of Panna National Park. The best time to visit is during the cooler months from November to March.
Khajuraho Hotels:
There are plenty of places to stay in Khajuraho from cheap to luxury. Many are conveniently located close to the temples. Here are the 5 Best Khajuraho Hotels for All Budgets.

Taj Mahal Story

Male Protagonist: Shah Jahan (Prince Khurram)
Female Protagonist: Mumtaz Mahal (Arjumand Banu Begum)

Shah Jahan met Mumtaz Mahal and fell in love. He married her after five years and they were leading a very happy life. While giving birth to their last child, Mumtaz Mahal died due to some complications. A few years later Shah Jahan built the world's most beautiful monument "Taj Mahal" in the memory of his wife.

One of the wonders of the world "Taj Mahal" has a beautiful love story behind its construction. Taj Mahal love story is about Shah Jahan and Mumtaz Mahal. Shah Jahan, initially named Prince Khurram, took birth in the year 1592. The son of Jehangir, the fourth Mughal emperor of India, he fell in love in Arjumand Banu Begum at first time. At that time he was 14 years old and she, a Muslim Persian princess, was 15. After meeting her, Shah Jahan went back to his father and declared that he wanted to marry her. Read on to know more about the love story behind Taj Mahal of Agra…

The match got solemnized after five years i.e., in the year 1612. Shah Jahan became the Emperor in the year 1628 and entrusted Arjumand Banu with the royal seal. He also bestowed her with the tile of Mumtaz Mahal, meaning the "Jewel of the Palace". Though Shah Jahan had other wives also, but, Mumtaz Mahal was his favorite and accompanied him everywhere, even on military campaigns. In the year 1631, when Mumtaz Mahal was giving birth to their 14th child, she died due to some complications.

It is said that Shah Mahal was so heartbroken after her death that he ordered the court into morning for two years. Some time after her death, Shah Jahan undertook the task of erecting the world's most beautiful monument in the memory of his beloved. It took 22 years and the labor of 22,000 workers to construct the monument, which is also said to be the last wish of Mumtaz Mahal. This magnificent monument came to be known as "Taj Mahal" and now counts amongst the Seven Wonders of the World.

This is the true story of the Taj Mahal of India, which has mesmerized many people with its bewitching beauty.

History of Taj Mahal
The history of the Taj Mahal tells us "why was the Taj Mahal built" and many other myths and facts associated with this wonderful structure. Mughal Emperor Shah Jahan erected the Taj Mahal in the memory of his beloved wife, Mumtaz Mahal. Shah Jahan (then Prince Khurram) met Mumtaz Mahal (then Arjumand Banu Begum) at the age of fourteen and fell in love at the first sight. She was a Muslim Persian princess and Shah Jahan was the son of the Mughal Emperor, Jehangir. Five years later, in 1612, they got married. As you read further you will come to know more about the history of the Taj Mahal at Agra…

Mumtaz Mahal, an inseparable companion of Shah Jahan, died in 1631, while giving birth to their 14th child. It is believed that during her last moments, Mumtaz Mahal obtained a promise from Shah Jahan that he will build world's most beautiful monument in her memory. But this has not been proven to be true, till date. However, Shah Jahan did indeed build a magnificent monument as a tribute to her wife, which we today know as the "Taj Mahal". Shah Jahan, himself also, lies entombed in this mausoleum along with his wife.

The construction of Taj Mahal started in the year 1631 and it took approximately 22 years to build it. An epitome of love, it made use of the services of 22,000 laborers and 1,000 elephants. It was built entirely out of white marble, which was brought in from all over India and central Asia. After an expenditure of approximately 32 million rupees (approx US $68000), Taj Mahal was finally completed in the year 1653. However, the history of Taj Mahal of India still has some gaps. For example, there are many theories regarding the architect of this magnificent monument.

Solar Energy

Solar thermal energy (
STE)[1] is a technology for harnessing solar energy for thermal energy (heat). Solar thermal collectors are defined by the USA Energy Information Administration as low-, medium-, or high-temperature collectors. Low temperature collectors are flat plates generally used to heat swimming pools. Medium-temperature collectors are also usually flat plates but are used for creating hot water for residential and commercial use. High temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production. STE is different from photovoltaics, which convert solar energy directly into electricity. While only 600 megawatts of solar thermal power is up and running worldwide in October 2009 according to Dr David Mills of Ausra, another 400 megawatts is under construction and there are 14,000 megawatts of the more serious concentrating solar thermal (CST) projects being developed.[2]

Low-temperature collectors
Of the 21,000,000 square feet (2,000,000 m2) of solar thermal collectors produced in the United States in 2006, 16,000,000 square feet (1,500,000 m2) were of the low-temperature variety.[3] Low-temperature collectors are generally installed to heat swimming pools, although they can also be used for space heating. Collectors can use air or water as the medium to transfer the heat to their destination.

Heating, cooling, and ventilation
In the United States, heating, ventilation, and air conditioning (HVAC) systems account for over 25 percent (4.75 EJ) of the energy used in commercial buildings and nearly half (10.1 EJ) of the energy used in residential buildings.[4][5] Solar heating, cooling, and ventilation technologies can be used to offset a portion of this energy.

Thermal mass materials store solar energy during the day and release this energy during cooler periods. Common thermal mass materials include stone, concrete, and water. The proportion and placement of thermal mass should consider several factors such as climate, daylighting, and shading conditions. When properly incorporated, thermal mass can passively maintain comfortable temperatures while reducing energy consumption. A solar chimney (or thermal chimney) is a passive solar ventilation system composed of a hollow thermal mass connecting the interior and exterior of a building. As the chimney warms, the air inside is heated causing an updraft that pulls air through the building. These systems have been in use since Roman times and remain common in the Middle East.

Solar space heating with air solar collectors is more popular in USA and Canada than heating with solar liquid collectors since most buildings already have a ventilation system for heating and cooling. The two main types of solar air panels are glazed and unglazed.

Glazed Solar Collectors are designed primarily for space heating and they recirculate building air through a solar air panel where the air is heated and then directed back into the building. These solar space heating systems require at least two penetrations into the building and only perform when the air in the solar collector is warmer than the building room temperature. Most glazed collectors are used in the residential sector.

Unglazed Solar Collectors are primarily used to heat ventilation air or ambient air and not building air. As these solar panels heat the fresh air for a building, they are ideally suited to commercial, industrial and institutional buildings with a high ventilation load. They only require one penetration into the building, or if existing fan inlets are used, then no additional penetrations are necessary. Heating ambient air allows solar energy to be utilized whenever the temperature in the collector is above ambient, not room temperature. This can provide twice the solar energy gain over space heating designs. The efficiency of a solar collector is highest when the temperature of the air entering the solar panel is equal ambient temperature. This occurs with solar heaters that draw outside air into the solar heater instead of room air.

The transpired solar panel is a low cost and high performance unglazed solar panel and is building integrated. It is currently the most popular type of solar air heating in North America. A painted metal panel, with small holes spaced uniformly across the entire absorber, is the main feature of the transpired collector. Sunlight strikes the dark surface which absorbs the heat. Solar heat conducts from the surface to the thermal boundary layer of air 1 mm thick next to the plate. This boundary layer of air is drawn into a nearby hole before the heat can escape by convection, virtually eliminating heat loss off the surface of the plate.

A Trombe wall is a passive solar heating and ventilation system consisting of an air channel sandwiched between a window and a sun-facing thermal mass. During the ventilation cycle, sunlight stores heat in the thermal mass and warms the air channel causing circulation through vents at the top and bottom of the wall. During the heating cycle the Trombe wall radiates stored heat.[6]

Solar roof ponds are unique solar heating and cooling systems developed by Harold Hay in the 1960s. A basic system consists of a roof-mounted water bladder with a movable insulating cover. This system can control heat exchange between interior and exterior environments by covering and uncovering the bladder between night and day. When heating is a concern the bladder is uncovered during the day allowing sunlight to warm the water bladder and store heat for evening use. When cooling is a concern the covered bladder draws heat from the building's interior during the day and is uncovered at night to radiate heat to the cooler atmosphere. The Skytherm house in Atascadero, California uses a prototype roof pond for heating and cooling.[7]

Active solar cooling can be achieved via absorption refrigeration cycles, desiccant cycles, and solar mechanical processes. In 1878, Auguste Mouchout pioneered solar cooling by making ice using a solar steam engine attached to a refrigeration device.[8] Thermal mass, smart windows and shading methods can also be used to provide cooling. The leaves of deciduous trees provide natural shade during the summer while the bare limbs allow light and warmth into a building during the winter. The water content of trees will also help moderate local temperatures.

Process heat
Solar process heating systems are designed to provide large quantities of hot water or space heating for nonresidential buildings [9].

Evaporation ponds are shallow ponds that concentrate dissolved solids through evaporation. The use of evaporation ponds to obtain salt from sea water is one of the oldest applications of solar energy. Modern uses include concentrating brine solutions used in leach mining and removing dissolved solids from waste streams. Altogether, evaporation ponds represent one of the largest commercial applications of solar energy in use today.[10]

Unglazed transpired collectors (UTC) are perforated sun-facing walls used for preheating ventilation air. UTCs can raise the incoming air temperature up to 22 °C and deliver outlet temperatures of 45-60 °C. The short payback period of transpired collectors (3 to 12 years) make them a more cost-effective alternative to glazed collection systems. As of 2009, over 1500 systems with a combined collector area of 300,000 m² had been installed worldwide. Representatives include an 860 m² collector in Costa Rica used for drying coffee beans and a 1300 m² collector in Coimbatore, India used for drying marigolds.[11][12]

A food processing facility in Modesto, California uses parabolic troughs to produce steam used in the manufacturing process. The 5,000 m² collector area is expected to provide 4.3 GJ per year.[13]

Medium-temperature collectors
These collectors could be used to produce approximately 50% and more of the hot water needed for residential and commercial use in the United States.[14] In the United States, a typical system costs $4000–$6000 and 30% of the system qualifies for a federal tax credit + additional state credit exists in about half of the states. With this incentive, the payback time for a typical household is four to nine years, depending on the state. Similar subsidies exist in parts of Europe. A crew of one solar plumber and two assistants with minimal training can install a system per day. Thermosiphon installation have negligible maintenance costs (costs rise if antifreeze and mains power are used for circulation) and in the US reduces a households' operating costs by $6 per person per month. Solar water heating can reduce CO2 emissions by 1 ton/year (if replacing natural gas for hot water heating) or 3 ton/year (if replacing electric hot water heating).[15][Per what?] Medium-temperature installations can use any of several designs: common designs are pressurized glycol, drain back, batch systems and newer low pressure freeze tolerant systems using polymer pipes containing water with photovoltaic pumping

Solar Drying
Solar thermal energy can be very useful in drying products such as fruits, grains, and fish. Crop drying by solar means is environmentally friendly as well as cost effective while improving the quality. The less money it takes to make a product, the less it can be sold for, pleasing both the buyers and the sellers. Technologies in solar drying include ultra low cost pumped transpired plate air collectors based on black fabrics. Solar thermal energy is helpful in the process of drying products by raising the heat while allowing air to pass through and get rid of the moisture

What is Nanotechnology?

What is Nanotechnology?

A basic definition: Nanotechnology is the engineering of functional systems at the molecular scale. This covers both current work and concepts that are more advanced.
In its original sense, 'nanotechnology' refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products.

The Meaning of Nanotechnology

When K. Eric Drexler (right) popularized the word 'nanotechnology' in the 1980's, he was talking about building machines on the scale of molecules, a few nanometers wide—motors, robot arms, and even whole computers, far smaller than a cell. Drexler spent the next ten years describing and analyzing these incredible devices, and responding to accusations of science fiction. Meanwhile, mundane technology was developing the ability to build simple structures on a molecular scale. As nanotechnology became an accepted concept, the meaning of the word shifted to encompass the simpler kinds of nanometer-scale technology. The U.S. National Nanotechnology Initiative was created to fund this kind of nanotech: their definition includes anything smaller than 100 nanometers with novel properties.

Much of the work being done today that carries the name 'nanotechnology' is not nanotechnology in the original meaning of the word. Nanotechnology, in its traditional sense, means building things from the bottom up, with atomic precision. This theoretical capability was envisioned as early as 1959 by the renowned physicist Richard Feynman.

I want to build a billion tiny factories, models of each other, which are manufacturing simultaneously. . . The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big. — Richard Feynman, Nobel Prize winner in physics

Based on Feynman's vision of miniature factories using nanomachines to build complex products, advanced nanotechnology (sometimes referred to as molecular manufacturing) will make use of positionally-controlled mechanochemistry guided by molecular machine systems. Formulating a roadmap for development of this kind of nanotechnology is now an objective of a broadly based technology roadmap project led by Battelle (the manager of several U.S. National Laboratories) and the Foresight Nanotech Institute.

Shortly after this envisioned molecular machinery is created, it will result in a manufacturing revolution, probably causing severe disruption. It also has serious economic, social, environmental, and military implications.

Four Generations

Mihail (Mike) Roco of the U.S. National Nanotechnology Initiative has described four generations of nanotechnology development (see chart below). The current era, as Roco depicts it, is that of passive nanostructures, materials designed to perform one task. The second phase, which we are just entering, introduces active nanostructures for multitasking; for example, actuators, drug delivery devices, and sensors. The third generation is expected to begin emerging around 2010 and will feature nanosystems with thousands of interacting components. A few years after that, the first integrated nanosystems, functioning (according to Roco) much like a mammalian cell with hierarchical systems within systems, are expected to be developed.



Some experts may still insist that nanotechnology can refer to measurement or visualization at the scale of 1-100 nanometers, but a consensus seems to be forming around the idea (put forward by the NNI's Mike Roco) that control and restructuring of matter at the nanoscale is a necessary element. CRN's definition is a bit more precise than that, but as work progresses through the four generations of nanotechnology leading up to molecular nanosystems, which will include molecular manufacturing, we think it will become increasingly obvious that "engineering of functional systems at the molecular scale" is what nanotech is really all about.

Conflicting Definitions

Unfortunately, conflicting definitions of nanotechnology and blurry distinctions between significantly different fields have complicated the effort to understand the differences and develop sensible, effective policy.

The risks of today's nanoscale technologies (nanoparticle toxicity, etc.) cannot be treated the same as the risks of longer-term molecular manufacturing (economic disruption, unstable arms race, etc.). It is a mistake to put them together in one basket for policy consideration—each is important to address, but they offer different problems and will require different solutions. As used today, the term nanotechnology usually refers to a broad collection of mostly disconnected fields. Essentially, anything sufficiently small and interesting can be called nanotechnology. Much of it is harmless. For the rest, much of the harm is of familiar and limited quality. But as we will see, molecular manufacturing will bring unfamiliar risks and new classes of problems.

General-Purpose Technology

Nanotechnology is sometimes referred to as a general-purpose technology. That's because in its advanced form it will have significant impact on almost all industries and all areas of society. It will offer better built, longer lasting, cleaner, safer, and smarter products for the home, for communications, for medicine, for transportation, for agriculture, and for industry in general.

Imagine a medical device that travels through the human body to seek out and destroy small clusters of cancerous cells before they can spread. Or a box no larger than a sugar cube that contains the entire contents of the Library of Congress. Or materials much lighter than steel that possess ten times as much strength. — U.S. National Science Foundation

Dual-Use Technology

Like electricity or computers before it, nanotech will offer greatly improved efficiency in almost every facet of life. But as a general-purpose technology, it will be dual-use, meaning it will have many commercial uses and it also will have many military uses—making far more powerful weapons and tools of surveillance. Thus it represents not only wonderful benefits for humanity, but also grave risks.

A key understanding of nanotechnology is that it offers not just better products, but a vastly improved manufacturing process. A computer can make copies of data files—essentially as many copies as you want at little or no cost. It may be only a matter of time until the building of products becomes as cheap as the copying of files. That's the real meaning of nanotechnology, and why it is sometimes seen as "the next industrial revolution."

My own judgment is that the nanotechnology revolution has the potential to change America on a scale equal to, if not greater than, the computer revolution. — U.S. Senator Ron Wyden (D-Ore.)

The power of nanotechnology can be encapsulated in an apparently simple device called a personal nanofactory that may sit on your countertop or desktop. Packed with miniature chemical processors, computing, and robotics, it will produce a wide-range of items quickly, cleanly, and inexpensively, building products directly from blueprints.

Mangal Pandey

Mangal Pande (born (presumably): July 19, 1827, died: 8 April 1857),


Also known as Shaheed Mangal Pande (Shaheed means martyr in Arabic and Hindustani), was a sepoy (soldier) in the 34th Regiment of the Bengal Native Infantry (BNI) of the British East India Company.
Pande was born in the village of Nagwa in district Ballia, Uttar Pradesh. There is some dispute over his exact place of birth. One account (Misra, 2005, see below) claims that Mangal Pandey was born in a Bhumihar brahmin family to Divakar Pandey of Surhupur village of Faizabad district’s Akbarpur Tehsil. He joined the British East India Company forces in 1849 at the age of 22, as per this account. Pandey was part of 5th Company of the 34th BNI regiment. He is primarily known for attacking his British officers in an incident that sparked what is known to the British as the Sepoy Mutiny of 1857 and to Indians as the First War of Indian Independence.



Since the attack was not a result of personal grudges but rather driven by ideological (religious/patriotic) motives, in India Pande is widely considered to be the First Warrior in India's long struggle for independence from the British rule. Some contemporary accounts suggest that Pande was under the influence of bhang (cannabis) at the time of this incidence. This claim however should be treated with a certain degree of reservation as it is not based on independent accounts. Moreover, this claim, even if true, does not rule out the possibility that Mangal Pandey could have been harboring a general grudge against the British rule in India that came to fore while under the influence of a drug. A further proof of his non-personal motives is delivered by accounts of British officers present at the scene. They recorded in numerous books that Pande used four-letter words for the British in general and incited his comrades to rise against the company rule..
At Barrackpore (now Barrackpur), near Calcutta on March 29, 1857, Pande attacked and injured his British sergeant on the parade ground, and wounded an adjutant with a sword after shooting at him, but instead hitting the adjutant's horse. He was however attacked by a native soldier called Shaikh Paltu who prevented him from killing the adjutant and later the sergant-major.
When General Joyce Hearsay ordered the Jemadar of the troops, a man called Ishari Pande, to arrest him, the Jemadar refused, as did the rest of the company except Shaikh Paltu. Mangal then turned the gun against himself, and used his foot to try to pull the trigger to shoot himself.
He failed, was captured and sentenced to death along with the Jemadar. Mangal Pandey was hanged on April 8. His execution was scheduled for April 18, but he was summarily executed 10 days prior to the date, fearing the possibility of a larger-scale revolt. The Jemadar Ishari Pandey was executed on April 22. The whole regiment was dismissed "with disgrace" on 6th May as a collective punishment, because it was felt that they harboured ill-feelings against their superiors. Other sepoys of the Bengal Army thought this was a harsh punishment. Shaikh Paltu was promoted on the spot to the post of a Havaldar (native sergant) by General Hearsay
The primary motivation behind Mangal's behavior is attributed to a new type of bullet cartridge used in the Enfield P-53 rifle introduced in the Bengal Army that year.
The cartridge was rumored to be greased with animal fat (primarily pig and cow fat, which are not consumed by either Hindus or Muslims, the primary religions in the Bengal Army) [1]. The cartidges had to be bitten to remove the cover, and that was abhorrent to the soldiers [2]. The general feeling was that this was intentional on the part of the British, to defile their religions.
Commandant Wheler of the 34th BNI was known as a zealous Christian preacher, and this may also have impacted the Company's behaviour. The husband of Captain Wilma Halliday of 56th BNI had the Bible printed in Urdu and Nagri and distributed among the sepoys, thus convincing them that the British were intent on converting them to Christianity [3].
Also, the 19th and 34th Bengal Native Infantry were stationed at Lucknow during the time of annexation of Awadh (anglicised to Oudh) under the Doctrine of Lapse on February 7, 1856.
The annexation had another implication for sepoys in the Bengal Army (a significant portion of whom came from that princely state). Before the annexation these sepoys had the right to petition the British Resident at the Awadh in Lucknow for justice - a significant privilege in the context of native courts. As a result of the annexation they lost that right, since that state no longer existed. Moreover, this action was seen by the residents of Awadh as an upfront by the British, as the annexation was done in violation of an existing treaty.
Thus, it was quite natural that sepoys were affected by the general discontent which was aroused with the annexation. In February 1857, both these regiments were situated in Barrakpur.
The 19th Regiment is important because it was the regiment charged with testing the new cartridges on February 26, 1857. The sepoys in that regiment refused, when ordered to fire [4]. The whole regiment was dismissed with dishonour from service in order to post an exemplary punishment.

The Enfield Rifle & Cartridge

The P-53 was officially known as the Pattern 1853 Enfield Rifle Musket. Introduced in the British Army by the War Department during 1854 in the Crimean War, they proved very effective at a range of 50 to 300 yards. It was introduced in the Bengal Army by the East India Company in early-1857.
The rifle used a Metford-Pritchitt cartridge that required the use of a heavy paper tube containing 2 1/2 drams (68 grains) of musket powder and a 530-grain, pure lead bullet. As the bullet incorporated no annular grease rings like the French and American minié ball bullets introduced in 1847, it was wrapped with a strip of greased paper to facilitate loading. The cartridge itself was covered with a thin mixture of beeswax and mutton tallow for waterproofing.
To load his rifle, the sepoy had to first bite off the rear of the cartridge to pour the powder down the barrel. he then inverted the tube (the projectile was placed in the cartridge base up), pushed the end-portion into the muzzle to the approximate depth of the bullet and tore off the remaining paper. The bullet could then be easily rammed on top of the charge.
Since Hindus consider cows as holy and Muslims regard pigs as dirty, native sepoys could be expected to have reservations in its usage. The company therefore kept this fact a secret. Thus, when it came out as a rumor, it had an even more damaging effect, as all kinds of rumors started spreading. For instance, it was thought that the British planned to make their sepoys outcaste in the society in order to force them to convert to Christianity. Another rumor said the British had manipulated the wheat flour distributed to the sepoy with bones of cows. The matters could have been worsened by the fact that an overwhleming number of sepoy in the Bengal Native Infantry was made of Brahmin sepoys from Awadh. As Brahmins are generally vegetarians and are not supposed to eat or touch meat, the resistance was even stronger.
The Commander-in-Chief, General George Anson reacted to this crisis by saying, "I'll never give in to their beastly prejudices," and despite the pleas of his junior officers, he did not compromise.
Later, the British contemplated reducing the discontent by allowing the sepoys to use their own grease made of Ghee (clarified butter). Lord Canning sanctioned a proposal of Major-General Hearsey to this effect. However, the proposal was shot down by the Meerut-based Adjutant-General of the Army Colonel C. Chester, who felt it would be tantamount to an admission of guilt and could therefore worsen the matter.[5] He falsely claimed that the sepoys had been using cartridges greased with mutton fat for years and that there was therefore no reason to give in now. This claim was however not correct as native sepoys had till then only used 'Brown Bess' Muskets for which unsmeared paper cartridges were employed. The Government, even while having every reason to know the truth, let itself be convinced and rescinded the order allowing the usage of Ghee. In fact, some historians, including contemporary observers such as Malleson ('The Indian Mutiny of 1857', edition 2005, pp. 15-31) regard an all-too-obvious contempt for the sensitivities of the Indians, displayed by some officers of the British-Indian Government, as one of the primary reasons that augmented, if not caused, the spread of the mutiny. Malleson, a British military officer stationed in 1857 in Calcutta, recounts many incidences in his analysis of the mutiny where British actions displayed a complete disregard for innocuous local norms and thus contributed to wide-spread discontentment. The Roti Rebellion', with its strong emotional elements, portrayed the spirit of the First War of Independence.

Inspiration Quotes

“Courage is the discovery that you may not win, and trying when you know you can lose.”
-Tom Krause quotes

“If you only do what you know you can do- you never do very much.”
-Tom Krause quotes

“Enthusiasm is excitement with inspiration, motivation, and a pinch of creativity.”
-Bo Bennett quotes

“Music is what feelings sound like.”

“Courage doesn't always roar. Sometimes courage is the quiet voice at the end of the day saying, "I will try again tomorrow.”
-Mary Anne Radmacher quotes

“You are the embodiment of the information you choose to accept and act upon. To change your circumstances you need to change your thinking and subsequent actions.”
-Adlin Sinclair quotes

“There are no failures - just experiences and your reactions to them.”
-Tom Krause quotes

“Your time is limited, so don't waste it living someone else's life. Don't be trapped by dogma - which is living with the results of other people's thinking. Don't let the noise of other's opinions drown out your own inner voice. And most important, have the courage to follow your heart and intuition. They somehow already know what you truly want to become. Everything else is secondary.”
-Steve Jobs quotes

GLOBAL WARMING

GLOBAL WARMING AWARENESS
Global Warming Skeptics - Skeptics of global warming think that global warming is not an ecological trouble.
Global Warming Facts - 8 Facts about Global Warming
Causes of Global Warming - The Green house gases are the main culprits of the global warming. The green house gases like carbon dioxide, methane, and nitrous oxide are playing hazards in the present times.
Green House Gasses are the ingredients of the atmosphere that add to the greenhouse effect.
Al Gore Global Warming Initiative - Gore has written a book that archives his advice that Earth is dashing toward an immensely warmer future.

The average facade temperature of the globe has augmented more than 1 degree Fahrenheit since 1900 and the speed of warming has been almost three folds the century long average since 1970. This increase in earth’s average temperature is called Global warming. More or less all specialists studying the climate record of the earth have the same opinion now that human actions, mainly the discharge of green house gases from smokestacks, vehicles, and burning forests, are perhaps the leading power driving the fashion.
The gases append to the planet's normal greenhouse effect, permitting sunlight in, but stopping some of the ensuing heat from radiating back to space. Based on the study on past climate shifts, notes of current situations, and computer simulations, many climate scientists say that lacking of big curbs in greenhouse gas discharges, the 21st century might see temperatures rise of about 3 to 8 degrees, climate patterns piercingly shift, ice sheets contract and seas rise several feet. With the probable exemption of one more world war, a huge asteroid, or a fatal plague, global warming may be the only most danger to our planet earth.

Global Warming Causes
As said, the major cause of global warming is the emission of green house gases like carbon dioxide, methane, nitrous oxide etc into the atmosphere. The major source of carbon dioxide is the power plants. These power plants emit large amounts of carbon dioxide produced from burning of fossil fuels for the purpose of electricity generation. About twenty percent of carbon dioxide emitted in the atmosphere comes from burning of gasoline in the engines of the vehicles. This is true for most of the developed countries. Buildings, both commercial and residential represent a larger source of global warming pollution than cars and trucks.
Building of these structures require a lot of fuel to be burnt which emits a large amount of carbon dioxide in the atmosphere. Methane is more than 20 times as effectual as CO2 at entrapping heat in the atmosphere. Methane is obtained from resources such as rice paddies, bovine flatulence, bacteria in bogs and fossil fuel manufacture. When fields are flooded, anaerobic situation build up and the organic matter in the soil decays, releasing methane to the atmosphere. The main sources of nitrous oxide include nylon and nitric acid production, cars with catalytic converters, the use of fertilizers in agriculture and the burning of organic matter. Another cause of global warming is deforestation that is caused by cutting and burning of forests for the purpose of residence and industrialization.

Global Warming is Inspiring Scientists to Fight for Awareness

Scientists all over the world are making predictions about the ill effects of Global warming and connecting some of the events that have taken place in the pat few decades as an alarm of global warming. The effect of global warming is increasing the average temperature of the earth. A rise in earth’s temperatures can in turn root to other alterations in the ecology, including an increasing sea level and modifying the quantity and pattern of rainfall. These modifications may boost the occurrence and concentration of severe climate events, such as floods, famines, heat waves, tornados, and twisters. Other consequences may comprise of higher or lower agricultural outputs, glacier melting, lesser summer stream flows, genus extinctions and rise in the ranges of disease vectors. As an effect of global warming species like golden toad, harlequin frog of Costa Rica has already become extinct. There are number of species that have a threat of disappearing soon as an effect of global warming. As an effect of global warming various new diseases have emerged lately. These diseases are occurring frequently due to the increase in earths average temperature since the bacteria can survive better in elevated temperatures and even multiplies faster when the conditions are favorable. The global warming is extending the distribution of mosquitoes due to the increase in humidity levels and their frequent growth in warmer atmosphere. Various diseases due to ebola, hanta and machupo virus are expected due to warmer climates. The marine life is also very sensitive to the increase in temperatures. The effect of global warming will definitely be seen on some species in the water. A survey was made in which the marine life reacted significantly to the changes in water temperatures. It is expected that many species will die off or become extinct due to the increase in the temperatures of the water, whereas various other species, which prefer warmer waters, will increase tremendously. Perhaps the most disturbing changes are expected in the coral reefs that are expected to die off as an effect of global warming. The global warming is expected to cause irreversible changes in the ecosystem and the behavior of animals.

A group of scientists have recently reported on the surprisingly speedy rise in the discharge of carbon and methane release from frozen tundra in Siberia, now starting to melt because of human cause increases in earth’s temperature. The scientists tell us that the tundra is in danger of melting holds an amount of extra global warming pollution that is equivalent to the net amount that is previously in the earth's atmosphere. Likewise, earlier one more team of scientists reported that the in a single year Greenland witnessed 32 glacial earthquakes between 4.6 and 5.1 on the Richter scale. This is a disturbing sign and points that a huge destabilization that may now be in progress deep within the second biggest accretion of ice on the planet. This ice would be enough to raise sea level 20 feet worldwide if it broke up and slipped into the sea. Each day passing brings yet new proof that we are now in front of a global emergency, a climate emergency that needs instant action to piercingly decrease carbon dioxide emissions worldwide in order to turn down the earth's rising temperatures and avoid any catastrophe.

It is not easy to attach any particular events to global warming, but studies prove the fact that human activities are increasing the earth’s temperature. Even though most predictions focus on the epoch up to 2100, even if no further greenhouse gases were discharged after this date, global warming and sea level would be likely to go on to rise for more than a millennium, since carbon dioxide has a long average atmospheric life span.

You Can Help Fight Global Warming

Many efforts are being made by various nations to cut down the rate of global warming. One such effort is the Kyoto agreement that has been made between various nations to reduce the emissions of various green house gases. Also many non profit organizations are working for the cause. Al Gore was one of the foremost U.S. politicians to heave an alarm about the hazards of global warming. He has produced a significantly acclaimed documentary movie called "An Inconvenient Truth," and written a book that archives his advice that Earth is dashing toward an immensely warmer future. Al Gore, the former vice president of United States has given various speeches to raise an awareness of global warming. He has warned people about the ill effects of Global warming and its remedies.

But an interesting side of the global warming episode is that there are people who do not consider global warming as something that is creating a problem. Skeptics of global warming think that global warming is not an ecological trouble. According to the global warming skeptics, the recent enhancement in the earth's average temperature is no reason for alarm. According to them earth's coastlines and polar ice caps are not at a risk of vanishing. Global warming skeptics consider that the weather models used to establish global warming and to forecast its impacts are distorted. According to the models, if calculations are made the last few decades must have been much worse as compared to actually happened to be. Most of the global warming skeptics believe that the global warming is not actually occurring. They stress on the fact the climatic conditions vary because of volcanism, the obliquity cycle, changes in solar output, and internal variability. Also the warming can be due to the variation in cloud cover, which in turn is responsible for the temperatures on the earth. The variations are also a result of cosmic ray flux that is modulated by the solar magnetic cycles.

Global Warming Skeptics

The global warming skeptics are of the view that the global warming is a good phenomenon and should not be stopped. There are various benefits of global warming according to them. According to the skeptics, the global warming will increase humidity in tropical deserts. Also the higher levels of carbon dioxide in the atmosphere trigger plant growth. As predicted, due to the global warming the sea levels will rise. But this can be readily adapted. Another argument of global warming skeptics is that earth has been warmer than today as seen in its history. The thought is that global warming is nothing to get afraid of because it just takes us back to a more natural set of environment of the past. Animals and plants appeared to do just fine in those eras of warm climate on the earth. According to few skeptics, the present chilly climate on the earth is an abnormality when judged over the geographical scale. Over geologic time, the earth’s mean temperature is 22 degrees C, as compared to today's 15.5 degrees C.

Bible Quotes

“Give, and it shall be given to you. For whatever measure you deal out to others, it will be dealt to you in return.”

“Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints. (Ephesians 6:18)”

“It is easier for a camel to go through the eye of a needle, than for a rich man to enter the kingdom of God”

“Great men are not always wise”

“A fool shows his annoyance at once, but a prudent man overlooks an insult”

“Destruction cometh; and they shall seek peace, and there shall be none.”

“Work hard and become a leader; be lazy and never succeed. (Proverbs 12:24)”

“Love is patient; love is kind
and envies no one.
Love is never boastful, nor conceited, nor rude;
never selfish, not quick to take offense.
There is nothing love cannot face;
there is no limit to its faith,
its hope, and endurance.
In a word, there are three things
that last forever: faith, hope, and love;
but the greatest of them all is love.”

“Be strong and of a good courage, fear not, nor be afraid...for the Lord thy God, he it is that doth go with thee; he will not fail thee, nor forsake thee.”

“Weeping may endure for a night, but joy cometh in the morning. (Psalms 30:5)”

“For the Lamb which is in the midst of the throne shall feed them, and shall lead them unto living fountains of waters: and God shall wipe away all tears from their eyes.”

“I know the plans I have for you, declares the Lord, plans to prosper you and not to harm you, plans to give you hope and a future. (Jeremiah 29:11)”

Erosion and Weathering

Photograph by David Alan Harvey


Weathering and erosion slowly chisel, polish, and buff Earth's rock into ever evolving works of art—and then wash the remains into the sea.

The processes are definitively independent, but not exclusive. Weathering is the mechanical and chemical hammer that breaks down and sculpts the rocks. Erosion transports the fragments away.

Working together they create and reveal marvels of nature from tumbling boulders high in the mountains to sandstone arches in the parched desert to polished cliffs braced against violent seas.

Water is nature's most versatile tool. For example, take rain on a frigid day. The water pools in cracks and crevices. Then, at night, the temperature drops and the water expands as it turns to ice, splitting the rock like a sledgehammer to a wedge. The next day, under the beating sun, the ice melts and trickles the cracked fragments away.

Repeated swings in temperature can also weaken and eventually fragment rock, which expands when hot and shrinks when cold. Such pulsing slowly turns stones in the arid desert to sand. Likewise, constant cycles from wet to dry will crumble clay.

Bits of sand are picked up and carried off by the wind, which can then blast the sides of nearby rocks, buffing and polishing them smooth. On the seashore, the action of waves chips away at cliffs and rakes the fragments back and forth into fine sand.

Plants and animals also take a heavy toll on Earth's hardened minerals. Lichens and mosses can squeeze into cracks and crevices, where they take root. As they grow, so do the cracks, eventually splitting into bits and pieces. Critters big and small trample, crush, and plow rocks as they scurry across the surface and burrow underground. Plants and animals also produce acids that mix with rainwater, a combination that eats away at rocks.

Rainwater also mixes with chemicals as it falls from the sky, forming an acidic concoction that dissolves rock. For example, acid rain dissolves limestone to form karst, a type of terrain filled with fissures, underground streams, and caves like the cenotes of Mexico's Yucatán Peninsula.

Back up on the mountains, snow and ice build up into glaciers that weigh on the rocks beneath and slowly push them downhill under the force of gravity. Together with advancing ice, the rocks carve out a path as the glacier slumps down the mountain. When the glacier begins to melt, it deposits its cargo of soil and rock, transporting the rocky debris toward the sea. Every year, rivers deposit millions of tons of sediment into the oceans.

Without the erosive forces of water, wind, and ice, rock debris would simply pile up where it forms and obscure from view nature's weathered sculptures. Although erosion is a natural process, abusive land-use practices such as deforestation and overgrazing can expedite erosion and strip the land of soils needed for food to grow.

Climate

Climate isn't the same thing as weather. Weather is the condition of the atmosphere over a short period of time; climate is the average course of weather conditions for a particular location over a period of many years.

One of the factors that influences climate is the angle of the sun's rays. In the tropics, between 23.5° N and 23.5° S, there is at least one time of year when the noontime sun is directly overhead and its rays hit at a direct angle. This produces a hot climate with relatively small temperature differences between summer and winter.

In the Arctic and Antarctic (north or south of 66.5° latitude), there are times of year when the sun is above the horizon 24 hours a day (a phenomenon known as midnight sun) and times when it never rises. Even in the summer, the sun is low enough for temperatures to be lower than in the tropics, but the seasonal changes are much greater than in equatorial regions. Interior Alaska has seen temperatures as high as 100 degrees Fahrenheit (38 degrees Celsius).

Farther from the Equator lie the temperate regions. These include the United States, Europe, China, and parts of Australia, South America, and southern Africa. They have the typical four seasons: winter, spring, summer, and fall.

Outside Influences

Climate is also controlled by wind, oceans, and mountains.

Winds bring moisture to land. North and south of the Equator the trade winds blow from the northeast and southeast, respectively. These winds converge in the tropics, forcing air to rise. This produces thunderstorms, humidity, and monsoons.

North and south of the trade winds, about 30° from the Equator, there is relatively little wind, and therefore little moisture blowing inland from the oceans. Also, dry air is sinking back to the surface, warming in the process. This is why many of the world's great desert regions—the Sahara, Arabia, Iran, Iraq, and chunks of Mexico—lie at the same latitude. A similar band of deserts lies to the south in Australia, South America, and southern Africa.

Mountains force wind to rise as it crosses over them. This cools the air, causing moisture to condense in clouds and rain. This produces a wet climate on the upwind side of the mountains and an arid "rain shadow" on the downwind side.

Oceans provide moisture that fuels rainstorms. They also buffer the temperature of coastal regions, regardless of latitude.

Climate Groups

In the early 1900s, climatologist Wladimir Köppen divided the world into five major climate groups.

Moist, tropical climates are hot and humid. Steppes and deserts are dry, with large temperature variations. Plentiful lakes, rivers, or nearby oceans give humid, midlatitude climates cool, damp winters, but they have hot, dry summers. Some of these climates are also called Mediterranean. Continental climates occur in the centers of large continents. Mountain ranges (or sheer distance) block off sources of moisture, creating dry regions with large seasonal variations in temperature. Much of southern Canada, Russia, and parts of central Asia would fall into this category. Cold, or polar, climates round out Köppen's list. A sixth region, high elevations, was later added to the classification system.

The Human Body

The Human Body module consists of four activities that engage students in thoughtful activities about the form and function of a most remarkable machine, their own body. Students discover how bones, joints, and muscles work together. They build model skeleton parts, study their stimulus/response systems, and see what it's like to perform routine tasks with certain joints immobilized. Integrated multimedia materials explain how we use food, air, and our senses.

In activity 1, Bones, students observe how the body moves while jumping rope and discuss the body systems that come into action, including the skeleton. Students focus on the skeleton and try to determine how many bones are in their bodies. Their initial counts are compared and refined as they study life-size photograps and posters of the human skeleton. Finally, the students work in pairs to assemble a 19-piece articulated model skeleton.

In activity 2, Joints, students investigate where bones meet and study the advantages of an articulated skeleton. They systematically perform everyday tasks while certain joints in their hands are immobilized. Through this fun and frustrating experience, students become aware of the versatility of movement afforded by joints. They organize the major joints by type and compare the movement of mechanical devices to the types of joints in the body.

In activity 3, Muscles, students investigate the power source for human movement, muscles. Students are provided with basic information about muscles: that they contract when they work, that muscles attach to bones with tissues called tendons, that muscles attach across joints to move bones, and that ligaments attach from bone to bone. Students work in pairs to build a model leg and foot that simulates the actions of jumping rope. They build a thumb that models the actions of the human thumb.

In activity 4, Stimulus/Response, students investigate coordinated movement in hand and foot response to visual stimuli. The students work in pairs with a falling cup device; one student holds the cup poised to fall, and the other student places his hand under the cup. When the responding student sees the cup start to fall, he pulls his hand out of the way. Hits and misses are recorded in a bar graph for the right hand, left hand, right foot, and left foot. Students compare the coordinated responses and investigate the effect of practice on response time.

The Human Body

The Human Body module consists of four activities that engage students in thoughtful activities about the form and function of a most remarkable machine, their own body. Students discover how bones, joints, and muscles work together. They build model skeleton parts, study their stimulus/response systems, and see what it's like to perform routine tasks with certain joints immobilized. Integrated multimedia materials explain how we use food, air, and our senses.

In activity 1, Bones, students observe how the body moves while jumping rope and discuss the body systems that come into action, including the skeleton. Students focus on the skeleton and try to determine how many bones are in their bodies. Their initial counts are compared and refined as they study life-size photograps and posters of the human skeleton. Finally, the students work in pairs to assemble a 19-piece articulated model skeleton.

In activity 2, Joints, students investigate where bones meet and study the advantages of an articulated skeleton. They systematically perform everyday tasks while certain joints in their hands are immobilized. Through this fun and frustrating experience, students become aware of the versatility of movement afforded by joints. They organize the major joints by type and compare the movement of mechanical devices to the types of joints in the body.

In activity 3, Muscles, students investigate the power source for human movement, muscles. Students are provided with basic information about muscles: that they contract when they work, that muscles attach to bones with tissues called tendons, that muscles attach across joints to move bones, and that ligaments attach from bone to bone. Students work in pairs to build a model leg and foot that simulates the actions of jumping rope. They build a thumb that models the actions of the human thumb.

In activity 4, Stimulus/Response, students investigate coordinated movement in hand and foot response to visual stimuli. The students work in pairs with a falling cup device; one student holds the cup poised to fall, and the other student places his hand under the cup. When the responding student sees the cup start to fall, he pulls his hand out of the way. Hits and misses are recorded in a bar graph for the right hand, left hand, right foot, and left foot. Students compare the coordinated responses and investigate the effect of practice on response time.

Cancer

Photograph by Justin Guariglia


A young woman exhales cigarette smoke in Shanghai, China. The People's Republic of China is both the world's largest producer and largest consumer of tobacco, which has led to an impending cancer epidemic in the most populous country on Earth.


Cancer is a disease that begins as a renegade human cell over which the body has lost control. In order for the body and its organs to function properly, cell growth needs to be strictly regulated. Cancer cells, however, continue to divide and multiply at their own speed, forming abnormal lumps, or tumors. An estimated 6.7 million people currently die from cancer every year.

Not all cancers are natural-born killers. Some tumors are referred to as benign because they don't spread elsewhere in the body. But cells of malignant tumors do invade other tissues and will continue to spread if left untreated, often leading to secondary cancers.

Cancers can start in almost any body cell, due to damage or defects in genes involved in cell division. Mutations build up over time, which is why people tend to develop cancer later in life. What actually triggers these cell changes remains unclear, but diet, lifestyle, viral infections, exposure to radiation or harmful chemicals, and inherited genes are among factors thought to affect a person's risk of cancer.

Lung cancer is the world's most killing cancer. It claims about 1.2 million victims a year. Most of those victims are smokers, who inhale cancer-causing substances called carcinogens with every puff. Experts say around 90 percent of lung cancer cases are due to tobacco smoking.

Breast cancer now accounts for almost one in four cancers diagnosed in women. Studies suggest the genes you inherit can affect the chances of developing the illness. A woman with an affected mother or sister is about twice as likely to develop breast cancer as a woman with no family history of the disease. Lifestyle may also have an influence, particularly in Western countries where many women are having children later. Women who first give birth after the age of 30 are thought to have a three times greater risk of breast cancer than those who became mothers in their teens.

Geographical Distinctions

There are also stark geographic differences, with incidence rates varying by as much as thirtyfold between regions. In much of Asia and South and Central America, for example, cervix cancer is the most deadly in females. However, in North America and Europe another kind of gynecological cancer, ovarian cancer, is a more serious threat.

Among males, southern and eastern Africa record the second and third highest rates of oesophageal, or gullet, cancer after China, but western and central regions of Africa have the lowest incidence in the world. Differences in diet may explain this.

Nevertheless, the reasons why many cancers develop remain elusive. Brain cancer, leukemia (blood cancer), and lymphoma (cancer of the lymph glands) are among types that still mystify scientists.

Treatments

Yet ever more people are surviving diagnosis thanks to earlier detection, better screening, and improved treatments. The three main treatment options are surgery, radiotherapy and chemotherapy. Radiotherapy, also called radiation therapy, involves blasting tumors with high-energy x-rays to shrink them and destroy cancerous cells. Chemotherapy employs cancer-killing drugs.

Even so, future cancer cases are predicted to climb, since the world's population is aging. The proportion of people over age 60 is expected to more than double by 2050, rising from 10 percent to 22 percent. This will add an estimated 4.7 million to the cancer death toll by 2030.