Group 1 Past Paper PDF - Scientific Revolution

**GROUP 1** ------------------------------- ABECO, DIEGS RAMIS ABORDE, NICOLE ESPAÑOLA ALAGAN, GRACEZY AUSAN ALPAD, NAFISAH TUAYON AQUINO, IAN KURT BARRERA BENITEZ, CRISTIAN JAY ALIGUIN CABARON, CLARENCE BATIRZAL CARDINAL, KENTH JOSHUA TUGO CASAMAYOR, MICHAELA ESCARPE --------...

**GROUP 1** ------------------------------- ABECO, DIEGS RAMIS ABORDE, NICOLE ESPAÑOLA ALAGAN, GRACEZY AUSAN ALPAD, NAFISAH TUAYON AQUINO, IAN KURT BARRERA BENITEZ, CRISTIAN JAY ALIGUIN CABARON, CLARENCE BATIRZAL CARDINAL, KENTH JOSHUA TUGO CASAMAYOR, MICHAELA ESCARPE ------------------------------- **The LEAP of Science and Technology during the Scientific Revolution (A.D.1600-A.D. 1700)** The **scientific revolution** was the emergence of modern science during the early modern period, when developments in mathematics, physics, astronomy, biology and chemistry transformed the views of society and nature. The scientific revolution began in Europe towards the end of the Renaissance period and continued through the late 18^th^ century, influencing the intellectual social movements known as the Enlightenment. ***Science and Technology Development:*** 1\. **Nicolaus Copernicus** in 1543. *De revolutionibus orbium coelestium* is often cited as marking the beginning of the scientific revolution. **2. William Gilbert** (1544-1603) published books *On the Magnet and Magnetic Bodies,* and the *Great Magnet the Earth* in 1600, which laid the foundations of a theory of magnetism and electricity. Gilbert provided a hyper-empirical study of magnets, magnetism, and electricity with speculations about cosmology. **3. Tycho Brahe (1546-1601),** a Danish nobleman. He is known for his accurate and comprehensive astronomical and planetary observations. He was assisted by Johannes Kepler, where the Latter used the information to develop his own theories in Astronomy. In November 1572, He discovered the " Tycho's Star' or the ' Star of 1572', a dramatic supernova believed to appear in Cassiopeia constellation which the sun and moon orbited the earth, while the other planets orbited the sun. (Geo-Heliocentirc theory or Tychonic theory). The crater Tycho on the moon is named after him, as in the crater Tycho Brahe on Mars. 4\. **Johannes Kepler** (1571-1630) first publication in astronomy called Cosmographic Mystery presented a stridently Copernican worldview dedicated to drawing together mathematical astronomy, physics, and a quasi-Pythagorean religious perspective in hope of a new astronomy; He published the First two of his three laws of planetary motion in 1609; published his Ad vitellioem paralipomena quibus astronomiae pars optica traditor (The Optical Part of Astronomy) where he argues that light rays are rectilinear, that they diminish in intensity by the inverse square of their distance as they travel from the light source; *Astronomia nova (New Astronomy)* shows that Mars moves non-uniformly in an elliptical path and proposes a quasi-magnetic power or virtue emanating from the sun as partial explanation for the planetary motions; *Harmonice mundi*(Harmonies of the world) presents his so-called "Third Law' which draws attention to the relationship between the annual periods of the planets and their distances from the sun. 5\. **Sir Francis Bacon (1561-1626)** published Novum Organum in 1620, which outlined a new system of logic based on the process of reduction, which he offered as an improvement over Aristotle's philosophical process of syllogism. He was a pivotal figure in establishing the scientific method of investigation. 6\. **Gallileo Galilei** (1564-1642) the famous Italian Astronomer who demonstrated that a projectile follows a parabolic path; 1608, he invented the telescope ('spyglass') which employs a convex objective lens and a concave eyepiece; 1609, he constructed his first telescope and turns it toward it toward the heaven and able to discover and argues there are innumerable stars invisible to the naked eye; He discovered mountains on the Moon and four moons circling Jupiter; later in 1610, Galileo observes the phrases of Venus, which suggested to him that waning and waxing planet must circle the Sun; discovered the sunspots; noted that Saturn appeared to have 'handles' and troubled over what could give to such an appearance; 1616, the year of the infamous Injunction against Galileo, was warned by the Inquisition not to hold or defend the hypothesis asserted in Copernicus' On the Revolutions, though it has been debated whether he was admonished not to 'teach in any way' the heliocentric theory. This work was in turn placed on the Index of Prohibited Books until corrected. 7\. **Rene Descartes** (1596-1650) published his Discourse on the Method in 1637, which helped to establish the scientific method. 8\. **Anton van Leeuwenhoek** (1632-1723) constructed powerful single lens microscopes and made extensive observations that he published around 1660, opening up the micro-world of biology. 9\. **Isaac Newton** (1643-1727) built upon the work of Kepler and Galileo. He showed that an inverse square law for gravity explained the elliptical orbits of the planets, and advanced the law of universal gravitation; in his Principa, Newton theorized his axiomatic three laws of motion. 10\. **Alexandre Koyre**, in the 20^th^ century, introduced the term "Scientific Revolution", centering his analysis on Galileo, and the term was popularized by *Butterfield* in his Origins of Modern Science. 11.**John Locke** is recognized founder of empiricism and proposed in An Essay Concerning Human Understanding (1689) that the only true knowledge that could be accessible to the human mind was that which was based on experience. He argued that the human mind was created as a tabula rasa, a "blank *tablet*", upon which sensory impressions were recorded and built up knowledge through a process of reflection. 12\. **Robert Boyle** (1627-1691) an English chemist considered to have refined the modern scientific method for alchemy and to have separated chemistry further from alchemy. Boyle is largely regarded today as the first modern chemist, and therefore one of the founders of modern *chemistry,* and one of the pioneers of modern experimental scientific method. Although Boyle was not an original discover, he is best known for Boyle's Law, which he presented in 1662: the law describes the inversely proportional relationship between the absolute *pressure* and *volume* of gas, if the temperature is kept constant within a closed system. He built an Air pump and many new instruments were devised in this period, which greatly aided in the expansion of scientific knowledge. 13\. Refracting telescopes first appeared in the Netherlands in 1608. The spectacle makers Hans Lippershey, **Zacharias Janssen** and **Jacob Metius** of Alkmaarall contributed to its invention. 14\. **Evangelista Torricelli** (1607-1647) was best known for his invention of the mercury barometer. The motivation for the invention was to improve on the suction pumps that were used to raise water out of the mines. **GROUP 2** --------------------------------- COLBERA, HERO BOY ARNOCO COMBITE, PRINCE JOHN SEÑEREZ CONDE, ANIE MAY SOLOREN CRISOLOGO, MARY GRACE AMORIO DALICAN, CHRISTOPHER MACOHAN DELOS ANGELES, ZAIRA MAE ESTARES, MARK JENSSEN PARONE FALLE, KATHLEEN NHOREN JOY BAEL FILIPINAS, BERNADETH BARRIO --------------------------------- **Lesson 9** **The Impact of Science and Technology on Society during the Industrial Revolution (A.D. 1730-A.D. 1950 in the Modern World)** In much of modern science the idea of progressive change, or evolution, has been of fundamental importance. In addition to biological evolution, astronomers have been concerned with stellar and galactic evolution, and astrophysicists and chemists with nucleosynthesis, or the evolution of the chemical elements. Geologists have discovered that the continents are not static entities but are also evolving; according to the theory of plate tectonics, some continents are moving away from each other while others are moving closer together. Physics in particular was shaken to the core around the turn of the century. The atom had been presumed indestructible, but discoveries of X-rays (1895), radioactivity (1896), and the electron (1897) could not be explained by the classical theories. The discovery of the atomic nucleus (1911) and of numerous subatomic particles in addition to the electron opened up the broad field of atomic and nuclear physics. Atoms were found to change not only by radioactive decay but also by more dramatic processes-nuclear fission and fusion-with the release of large amounts of energy. - **Albert Einstein**- *theory of relativity* - Radioactive isotopes have also found application in geological dating. - Introduction of microscope by the Janssen team that paved way for the establishment of the cell theory and study of minute things. **Charles Darwin** proposed the natural selection as an explanation of evolution. Darwin's complete theory is published in "On the Origin of Species" in 1859. Gregor Mendel's theory of Genetics, he observed and studied the pattern of inheritance using a pea plant and developed the Mendelian Principles of Heredity. - Louis Pasteur a French scientist known as the father of microbiology. He pioneered pasteurization, a process of heating milk to a high temperature and pressure to eliminate souring caused bacteria. - Hugo de Vries around the turn of the century biological evolution came to be interpreted in terms of mutations that result in a genetically distinct species; the survival of a give species was thus related to its ability to adapt to its environment through such mutations. - The development of *biochemistry* and the recognition that most important biological processes take place at the molecular level led to the rapid growth of the field of molecular biology, with such fundamental results as the discovery of the structure of *deoxyribonucleic acid* (DNA), the molecule carrying the genetic code. - Modern medicine has profited from this explosion of knowledge in biology and biochemistry, with new methods of treatment ranging from penicillin, insulin, and a vast array of other drugs to pacemakers for weak hearts and implantation of artificial or donated organs. - In *astronomy* ever larger telescopes have assisted in the discovery that the sun is a rather ordinary star in a huge collection of stars, the Milky Way, which itself is only one the galaxies, that in general are expanding away from each other. - The study of remote objects, billions of light-years from the earth, has been carried out at all wavelengths of *electromagnetic radiation,* with some of the most notable results being made in radio astronomy, which has been used to map the Milky Way, study quasars, pulsars, and other unusual objects, and detect relatively complex organic molecules floating in space. - The *electronics industry*, born in the early 20^th^ cent., has advanced to the point where a complex device, such as a computer, that once might have filled an entire room can now be carried in an attache case. The electronic computer has become one of the key tools of modern industry. Electronics has also been fundamental in developing new communications devices (radio, television, laser). - A *Watt steam engine*. The steam engine, made of iron and fueled primarily by *coal,* became widely used in Great Britain during the Industrial Revolution **Important Technological Developments** **Metallurgy:** A major change in the metal industries during the era of the Industrial Revolution was the replacement of wood and other bio-fuels with coal. For a given amount of heat, coal required much less labour to mine than cutting wood and converting it to charcoal, and coal was more abundant than wood. *James Watt and Matthew Boulton*, had succeeded by 1778 in perfecting his steam engine. Which incorporated a series of radical improvements. Notably the closing off of the upper part of the cylinder thereby making the low pressure steam drive the top of the piston instead of the atmosphere, use of a steam jacket and the celebrated separate steam condenser chamber. **Machine tools**: created a demand for metal parts used in machinery. This led to the development of several machine tools for cutting metal parts. **Chemicals:** The large scale production of chemicals such as sulphuric acid by the lead chamber process was invented by the Englishmen John Roebuck. Sulphuric acid is used for pickling (removing rust) iron and steel, and for bleaching cloth. Nicolas Leblanc, in 1791 introduced a method for the production of sodium carbonate. Sodium carbonate had many uses in the glass, textile, soap, and paper industries. The development of bleaching powder calcium hypochlorite, revolutionized the bleaching processes in the textile industry by dramatically reducing the time required for the traditional process then in use, which required repeated exposure to the sun in bleach fields after soaking the textiles with alkali or sour milk. **Cement:** In 1824 Joseph Aspdin, a British bricklayer turned builder, patented a chemical process for making Portland cement which was an important advance in the building trades. This process involves sintering a mixture of clay and limestone to about 1400°C, then grinding it into a fine powder which is then mixed with water, sand and gravel to produce concrete. Cement was used on a large scale in the construction. **Gas lighting:** Though others made a similar innovation elsewhere, the large-scale introduction of this was the work of William Murdoch, an employee of Boulton and Watt, the Birmingham steam engine pioneers. The process consisted of the large-scale gasification of coal in furnaces, the purification of the of the gas (removal of Sulphur, ammonia, and heavy hydrocarbons), and its storage and distribution. **Glass making:** A new method of producing glass, known as the cylinder process, was developed in Europe during the early 19^th^ century. In 1832, this process was used by the Chance Brothers to create sheet glass. **Paper machine:** A machine for making a continuous sheet of paper on a loop of wire fabric was patented in 1798 by Nicholas Louis Robert. **Agriculture:** improved agricultural productivity freed up workers to work in other sectors of the economy. Industrial technologies that affected farming included the seed drill, the Dutch plough, which contained iron parts, and the threshing machine. **Transportation**: At the beginning of the Industrial Revolution, inland transport was by navigable rivers and roads, with coastal vessels employed to move heavy goods by sea. Wagon ways were used for conveying coal to rivers for further shipment. From astounding automobile and the early airplane to the modern supersonic jet and the giant rocket that has taken astronauts to the moon. Transportation improvements, such as canals and improved roads, also lowered food costs. Railroads were introduced near the end of the Industrial Revolution. Canals were the first technology to allow bulk materials to be economically transported long distances inland. Building of canals dates to ancient times. The Grand Canal in China, " the world's largest artificial waterway and oldest canal still in existence", parts of which were started between the 6^th^ and 4^th^ centuries BC, is 1,121 miles (1804km) long and links Hangzhou with Beijing. Food and nutrition: food supply had been increasing and prices falling before the Industrial Revolution due to better agricultural practices; Housing: Living conditions during the Industrial Revolution varied from splendor for factory owners to squalor for workers. The Industrial Revolution also created a middle class of professionals, such as lawyers and doctors, who lived in much better conditions. **Clothing and consumer goods:** Consumers benefited from falling prices for clothing and household articles such as cast iron cooking utensils, and in the following decades, stoves for cooking and space heating. **GROUP 3** ------------------------------------- GALLARDE, LYNIE CARREON HIMAN, MARIE ANN BONION LABANGIN, RAMIL BUKA LAGOS, JEROME GULA LEDESMA, REMY CYDREX DELOS REYES LUDA, CHRISTIAN CASANTOSAN MAGLASANG, SHEILA MAE MANGUILIMUTAN MAGTANONG, JASTINE GRAVELA ------------------------------------- **Science, Technology and Society in the 20^th^ Century** There are heaps of developments of science and technology during this century and it keeps on upgrading. The following are some of the remarkable are some of the remarkable invention that had major impact on human being. **The Airplane** An **airplane** or **aeroplane** was invented by the Wright brothers, Wilbur and Orville. It is a powered, Fixed-wing aircraft that is propelled, sustained, powered flights on December 17, 1903 in Kitty Hawk, North Carolina. On Jan. 1, 1914. The St. Petersburg-Tampa Airboat Line became the world's first scheduled passenger airline service, operating between St. Petersburg and Tampa, Florida. It was a short-lived undertaking but it paved the way for today's daily transcontinental flights. The extensive uses of airplanes include recreation, transportation of goods and people, military, and research. Commercial aviation is a massive industry involving the flying of tens of thousands of passengers daily on airlines. Most airplanes are flown by a pilot on board the aircraft, but some are designed to be remotely or computer-controlled. Airplanes had a presence in all the major battles of World War II. The first jet aircraft was the German Heinkel He 178 in 1939. The first jet airliner, the de Havilland Comet, was introduced in 1952.The Boeing 707, the first widely successful commercial jet, was in commercial service for more than 50 years, from 1958 to at least 2013. **Computers** A computer is an electronic machine that accepts information, stores it, processes it according to the instructions provided by a user and then returns the result. Today, computers have become part of our everyday activities. While computers as we know them today are relatively recent, the concepts and ideas behind computers have quite a bit of history. Charles Babbage referred to as 'the father of computers', conceived an analytical engine in 1830 which could be programmed with punched cards to carry out calculations. It was different from its predecessors because it was able to make decisions based on its own computations, such as sequential control, branching and looping. Konrad Zuse built the very first electronic computers in Germany in the period 1935 to 1941. The Z3 was the first working, programmable and fully automatic digital computer. Zuse is often regarded as the 'inventor of the computer'. The british built the Colossus and the Americans built the Electronic Numerical Integrator Analyzer and Computer, or ENIAC between 1943 and 1945. Both Colossus and ENIAC relied heavily on vacuum tubes, which can act as an electronic switch that can be turned on or off much faster than mechanical switches. Computer systems using vacuum tubes are considered the first generation of computers. The first semiconductor transistor was invented in 1926, but only in 1947 was it developed into a solid-state, reliable transistor for the use in computers. Similar to a vacuum tube, a transistor controls the flow of electricity, but it was only a few millimeters in size and generated of computers. In 1954, IBM introduced the first mass-produced computer. By 1958 it became possible to combine several components, including transistors, and the circuitry connecting them on single piece of silicon. This was the first integrated circuit. Computer systems using integrated circuits are considered the third generation of computers. Integrated circuits led to the computer processors we use today. Computers became quickly more powerful. By 1970 it became possible to squeeze all the integrated circuits that are part of a single computer on a single chip a microprocessor. Computer systems using microprocessors are considered the fourth generation of computers. In the early 1970s computers were still mostly used by larger corporations, government agencies and universities. The first device that could be called a personal computer was introduced in 1975. The following are some of the Highlighted development of computer: - Steve Jobs and Steve Wozniak introduce Apple Computers on April Fool's Day and roll out the Apple I, the first computer with single-circuit board in 1976. - The firt IBM personal computer, code-named " Acorn", was introduced. It uses Microsoft's MS-DOS operating system. It has an Intel chip, two floppy disks and an optional color monitor in 1981 - The first dot-com domain name was registered on March 15, years before the World Wide Web would mark the formal beginning of Internet history in 1985. - Tim Berners-Lee, a researcher at CERN, the high-energy physics laboratory in Geneva, develops HyperText Markup Language (HTML), giving rise to the World Wide Web (WWW) in 1990. - The Pentium microprocessor advances the use of graphics and music on PCs on 1993 - PCs became gaming machines as "Command & Conquer," "Alone in the Dark 2," "Theme Park," "Magic Carpet," "Descent" and "Little Big Adventure" were among the games to hit the market in 1994. - The term Wi-Fi becomes part of the computing language and users begin connecting to the internet without wires in 1999. - Apple unveils the Mac OS X operating system, which provides protected memory architecture and pre-emptive multi-tasking, among other benefits in 2001. - Mozilla's Firefox 1.0 challenges Microsoft's Internet Explorer, the dominant Web browser, Facebook, a social networking site launces in 2004. - Youtube, a video sharing service, is founded, Google acquires Android, a Linux-based mobile phone operating system in 2005. - Apple introduces the MacBook Pro, its first intel-based, dual-core mobile computer, as well as an Intel-based iMac. Nintendo's Wii game console hits the market in 2006. - The iPhone brings many computer functions to the smartphone in 2007. - Google releases the Chromebook, a laptop that runs the Google Chrome OS in 2011. - Facebook gains 1 billion users on October 4, 2012. - The first reprogrammable quantum computer was created in 2016. - The Defense Advanced Research Projects Agency (DARPA) is developing a new "Molecular Informatics" program that uses molecules as computers (2017). **GROUP 4** -------------------------------- MANBURIS, REYNEIL ZATA MOHAMMAD, DATU BENCER AMBALGAN MORALES, DIANA JOY DUMDUMAYA MULA, JOHN REY DELA REYNA NABE, KENJIE LUMOGDANG NACARIO, MAYNARD KARL DE JUAN ORTEGA, IAN DAVE DELA CRUZ PRANDE, RENELYN COMBITE -------------------------------- **Magnetic Resonance Imaging** Magnetic resonance imaging (MRI) is a non-invasive medical test that physicians use to diagnose conditions. Magnetic resonance imaging (MRI) of the body uses a powerful magnetic field, radio waves or pulse and a computer to produce detailed pictures of the inside of your body such organs, soft tissues, bone and virtually all other internal body structures. It may be used to help diagnose the presence of certain disease and abnormalities or monitor treatment for a variety of conditions within the body. **The Internet** The internet was the work of dozens of pioneering scientists, programmers and engineers who each developed new features and technologies that eventually merged to become the " information superhighway" we know today. It started in early 1900 when **Nikola Tesla** toyed with the idea of a "world wireless system". **Paul Otlet and Vannevar Bush** conceived of mechanized, **searchable storage systems** of books and media in the 1930s and 1940s. J. **C.R. Licklider** popularized the idea of an "Intergalactic Network" (can be transferred sa earth kag planet) of computers. These ground breaking ideas landed him a position as director of the U.S department of Defense Advanced Research Projects Agency (ARPA), the government agency responsible for creating a time-sharing network of computers known as ARPANET, the precursor to today's internet in 1960. **Leonard Kleinrock** invented the **packet switching** (nagatransfer sang information sa ARPA. pwede niya matransfer ang inofrmation from other places), a method for effectively transmitting electronic data that would later become one of the major building blocks of the Internet. **ARPANET** used packet switching to allow multiple computers to communicate on a **single network.** **Robert Kahn and Vinton Cerf** in 1970, developed **Transmission Control Protocol and Internet Protocol, or TCP/IP,** a communications model that set standards for how data could be transmitted between multiple networks (naay mga protocols na daad ang inormation sa net is factual, information and reliable). In 1972, **Ray Tomlinson** introduced network email(email and gmails). ARPANET adopted January 1, 1983, and from these researchers began to assemble the "network of networks" that became the modern Internet. **Tim Berners-Lee** invented the World Wide Web (hyperlinks used to search for files and articles) in 1990. The web served as the most common means of accessing data online in the form of websites and hyperlinks. The web helped popularize the Internet among the public, and served as a crucial step in developing the vast trove of information that most of us now access on a daily basis. During the 1980s, the National Science Foundation started to build a nationwide computer network that included its own supercomputers, called NSFNET. ARPANET had grown well beyond the needs of the Department of Defense, and so the NSF took control of the "civilian nodes". In 1990, ARPANET was officially decommissioned. Ultimately, the NSF aimed to build a network that was independent of government funding. The NSF lifted all restrictions on commercial use on its network in 1991 and in 1995, the Internet was officially privatized. At the time, the Internet was 50,000 networks strong, spanned seven continents, and reached into space. **Optical Fiber** In 1880 Alexander Graham Bell created a very early precursor to fiber-optic communications, the world's first wireless telephone (Photo phone). Bell considered it his most important invention. The device allowed for the transmission medium, the Photo phone would not prove practical until advances in laser and optical fiber technologies permitted the secure transport of light. **Air Conditioning System** Primitive air-conditioning system have existed since ancient times. Attempts to control indoor temperatures began in ancient Rome, where wealthy citizens took advantage of the remarkable aqueduct system to circulate cool water through the walls of their homes. The emperor Elagabalus in the third century, built a mountain of snow, imported from the mountains via donkey trains and put it in the began garden next to his villa to keep cool during the summer, but this was so costly and inefficient. Such luxuries disappeared during the Dark Ages, and large-scale air-conditioning efforts didn't resurface in the West. **Gene Therapy (cures defective genes)** Gene therapy to treat genetic diseases at the molecular level by correcting what is wrong with defective genes. The first gene therapy was approved in the European Union in 2012, after two decades of dashed expectations. This approved boosted the investment in developing gene therapies. **3D Metal Printing** 3D Metal Printing is one of the advances in the technology that provide instant metal fabrication. This innovation enables the ability to create large, intricate metal structures on demand and therefore could revolutionize manufacturing. It gives the manufacturers the ability to make a single or small number of metal parts much more cheaply than using existing mass-production techniques. **Artificial Embryos** Artificial Embryos are made from stem cells alone without using egg or sperm cells. It is a breakthrough that will open new possibilities for understanding how life comes into existence-but clearly also raises vital ethical and even philosophical problems. **Cell-free Fetal DNA testing** Pregnant women sometimes need to have cells of their fetus tested for chromosomal defects such as Edwards Syndrome and Down Syndrome. These tests require an acquisition of cells that are quite invasive for the unborn baby. The test brought risk of miscarriage and increased stress for pregnant mothers. With medical advances, it is now possible for doctors to test cell-free Fetal DNA by using the mother's blood. This advance has become more widely used and accepted internationally in the past year. **Cancer nanotherapy** Nano devices and technology are already in wide use, and as the years pass, the technology in pharmaceuticals and medicine will only continue to improve. One of which is an emerging cancer treatment technology that implements nanomaterials in a more aggressive method. For example, researchers at Israel's Bar-Ilan University have developed nanobots to target and deliver drugs to defective cells, while leaving healthy ones unharmed. **GROUP 5** -------------------------------- RAOTRAOT, ARNEL SISGADOS SALAZAR, CARLOS AGUIRRE TOG, CHRISTINE LACOT TORRENTE, PRINCESS JANE TEDERA VILLAS, STEPHANIE PANINSORO BORLASA, MICKO FLANG, KRIZZIA ANNE BEHEMINO REPONTE, REY MARK GUIÑES -------------------------------- **CURRENT ISSUES ARISING FROM THE APPLICATION OF SCIENCE AND TECHNOLOGY** **Climate Change** The Earth's climate has changed throughout history. Just in last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era- and of human civilization. Most of these climate changes are attributed to very small variations in Earth's orbit that change the amount of solar energy our planet receives. Earth is a very special planet-it orbits close enough to the sun to receive a lot of energy, but far enough away not to be scorched. To help these conditions constant, our planet is wrapped in a layer of greenhouse gases. This layer acts like a blanket, keeping the earth warm and shielding it from the cold of universe. **Climate change** is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). **Global climate change** has already had observable effects on the environment. Glaciers have shrunk, ice on rivers and lakes is breaking up earlier, plant and animal ranges have shifted and trees are flowering sooner. Effects that scientists had predicted in the past would result from global climate change are now occurring: global temperature rise, Shrinking ice sheets or loss of sea ice, accelerated sea level rise and longer, more intense heat waves, water acidification and extreme events. Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities, and most of the leading scientific organizations worldwide have issued public statements endorsing this position. One manifested of climate change is **global warming.** **What is global warming?** **Global warming** refers to the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation. In common usage the term refers to recent warming and implies a human influence. Most of the observed increase in globally averaged temperatures since the mid-20^th^ century is very likely of the surface and lower atmosphere by increasing the greenhouse effect. Natural phenomena such as solar variation combined with volcanoes also produced greenhouse effect. **What causes climate change?** Human activities like mining, wrong practices in agriculture, illegal logging, burning of fossil fuel, deforestation, too much car that emits carbon monoxide and carbon dioxide and producing industrial waste are believe to be the sources of greenhouse gasses that in the long run cause the climate change. **The Greenhouse gases and effect** - Small amounts of heat trapping gases such as water vapor (H~2~0), carbon dioxide (CO~2~), ozone (O~3~), methane CH~4~,nitrous oxide (N~2~O) and chlorofluorocarbon (CFCs) play a key role in determining the earth's average temperature and thus its climates. - Together, these gases are known as greenhouse gases. They allow light, infrared radiation, and some ultraviolet radiation from the sun to pass through the troposphere. The earth's surface then absorbs much of this solar energy and degrade it to longer wave infrared radiation (that is Heat), which then rises into the troposphere, some of this heat escapes into space, some is absorbed by molecules of greenhouse gases, warming the air. This natural trapping of heat in the troposphere is called greenhouse effect. - The greenhouse effect first proposed by Swedish chemist Svante Arrhenius in 1896, has been confirmed by numerous laboratory experiments and atmospheric measurements. - Signicance: the earth would be a cold and lifeless planet with an average surface temperature of -18°C. - Measured atmospheric levels of certain greenhouse gases- CO~2,~ CFCs, methane, and nitrous oxide-have risen substantially in recent decades-caused by human activities burning fossil, fuels, agriculture, deforestation, and use of CFCs. **Carbon dioxide concentration**- Carbon dioxide is responsible for 50-60% of the global warming from greenhouse gases produced by human activities since pre-industrial times. The main sources of fossil fuel burning: coal, oil and natural gas (75%) and land clearing and burning (25%). Carbon dioxide (CO2 is nevertheless the main driver of the greenhouse effect. Because of this layer of greenhouse gas is getting thicker, which is in turn making the Earth warmer. **Chlorofluorocarbon**-contribute to global warming in the troposphere and deplete ozone in the stratosphere. The main sources are leaking air conditioners and refrigerators, evaporation of industrial solvents. **Methane concentration**- Methane is produced when anaerobic bacteria break down organic matter in moist places that lack oxygen. These areas include swamps and other natural wetlands, rice paddies and landfills, intestinal tract of cattle, sheep, and termites. **Nitrous oxide concentration**-Nitrous oxide can trap heat in the troposphere and deplete ozone in the stratosphere. It is released from nylon production, burning of biomass and nitrogen fertilizers in soil, livestock wastes. **What is the scientific consensus about future global warming and its effects?** - According to IPCC (Intergovernmental Panel on Climate Change) the earth's mean surface temperature will rise 1-3.5°C between 1990 and 2100. - The northern hemisphere should warm more and faster than southern hemisphere because the latter has more heat absorbing ocean than the land and because water cools more slowly than land. **Some possible effects of a warmed world** A warmer global climate could have a number of possible effects: - Changes in Food production; reduce water supplies - Change in the makeup and location of many world's forests. - Can cause massive wild fires - Reduction in biodiversity due to loss of habitat; destroying the coral reefs - Water in the oceans would expand and lead to rise in sea level. - Warming at the poles caused ice sheets and glaciers to melt, the global sea level would rise far more, melting of polar ice caps - Weather extremes are expected to increase in number and severity - Poses threats to human health, affects the respiratory tract increasing air pollution in winter months - Drought - Lead to a growing number of environment refugees. Causing social disorder and political instability. **How can we lower down the possible outcome of global warming?** -Get involved-cut fossil use in half -improve energy efficiency; switch off light when not in use -shift to renewable energy resources -reduce deforestation -use sustainable agriculture -slow population growth -remove carbon dioxide from smoke stack and vehicle emissions -plant and tend trees; green your community -trim production of industrial waste; encourage practices of 3R's -Full implementation of laws concerning conservation of the environment and the planet Earth.