miércoles, 26 de septiembre de 2012


Mariana Tomás-Laura Rial-Gabriela Varela

Characteristics of Igneous Rocks

Igneous rocks are produced by the crystallization and solidification of molten magma. Magma forms when rock is heated to high temperatures (between 625 and 1200° Celsius) beneath the Earth's surface. The exact temperature needed to melt rock is controlled by several factors. Chemistry of the rock material, pressure, presence of gases (like water vapor) all influence when melting occurs. Most of the heat required to melt rock into magma comes from the Earth's central internal region known as the core. Scientists estimate that the temperature of the Earth's core is about 5000° Celsius. Heat moves from the Earth's core towards the solid outer crust by convection and conduction. Convection moves hot  plumes of magma vertically from the lower mantle to the upper mantle. Some of these plumes melt through the Earth's solid lithosphere and can produce intrusive igneous features and extrusive igneous features on the surface. Heat can also be generated in the lower lithosphere through friction. The tectonic movement of subducted crustal plates can generate enough heat (and pressure) to melt rock. This fact explains the presence of volcanoes along the margin of some continental plates.





Seven Ancient Wonders of the World



                   Seven Ancient Wonders of the World

Click here to find out more!



Jessica Alvez da Cruz, Katherine Berasategui, Mariana Sánchez

Fuente: http://www.history.com/topics/seven-ancient-wonders-of-the-world


The amazing works of art and architecture known as the Seven Wonders of the Ancient World serve as a testament to the ingenuity, imagination and sheer hard work of which human beings are capable. They are also, however, reminders of the human capacity for disagreement, destruction and, possibly, embellishment. As soon as ancient writers compiled a list of "seven wonders," it became fodder for debate over which achievements deserved inclusion. Ultimately, human hands joined with natural forces to destroy all but one of the wonders. Furthermore, it is possible that at least one of the wonders might not have existed at all. Still, all seven continue to inspire and be celebrated as the remarkable products of the creativity and skill of Earth’s early civilizations.


Great Pyramid of Giza, Egypt

The Great Pyramids, located at Giza on the west bank of the Nile River north of Cairo, are the only wonder of the ancient world that has survived to the present day. The three pyramids--Khufu (Cheops), Khafra (Chephren) and Menkaura (Mycerimus)--were built between 2700 B.C. and 2500 B.C. as royal tombs. The largest and most impressive is Khufu, which covers 13 acres and is believed to contain more than 2 million stone blocks that weigh from two to 30 tons each. For more than 4,000 years, Khufu reigned as the tallest building in the world. In fact, it took modern man until the 19th century to build a taller structure. Amazingly, the nearly symmetrical pyramids were built without the aid of modern tools or surveying equipment. Scientists believe that the Egyptians used log rollers and sledges to move the stones into place.The sloped walls, which were intended to mimic the rays of Ra, the sun god, were originally built as steps, and then filled in with limestone. The interior of the pyramids included narrow corridors and hidden chambers in an unsuccessful attempt to foil grave robbers. Although modern archeologists have found some great treasures among the ruins, they believe most of what the pyramids once contained was looted within 250 years of their completion.

Hanging Gardens of Babylon

According to ancient Greek poets, the Hanging Gardens of Babylon were built near the Euphrates River in modern-day Iraq by the Babylonian king Nebuchadrezzar II around 600 B.C. The gardens were said to have been planted as high as 75 feet in the air on a huge square brick terrace that was laid out in steps like a theater. The king allegedly built the towering gardens to ease his lover Amytis’ homesickness for the natural beauty of her home in Media (the northwestern part of modern-day Iran). Later writers described how people could walk underneath the beautiful gardens, which rested on tall stone columns. Modern scientists have deduced that for the gardens to survive they would have had to be irrigated using a system consisting of a pump, waterwheel and cisterns to carry water from the Euphrates many feet into the air. Though there are multiple accounts of the gardens in both Greek and Roman literature, none of them are firsthand, and no mention of the gardens has been found in Babylonian cuneiform inscriptions. As a result, most modern scholars believe that the existence of the gardens was part of an inspired and widely believed but still fictional tale.

Statue of Zeus at Olympia

The famed statue of Zeus was crafted by the Athenian sculptor Phidias and completed and placed in the temple of Zeus at Olympia, site of the ancient Olympics, around the mid-fifth century B.C. The statue depicted the god of thunder seated bare-chested at a wooden throne. Holding up the thrones’ armrests were two carved sphinxes, mythical creatures with the head and chest of a woman, the body of lion and the wings of a bird. The statue of Zeus was richly decorated with gold and ivory. At 40 feet, it was so tall that its head nearly touched the top of the temple. According to legend, the sculptor Phidias asked Zeus for a sign of his approval after finishing the statue; soon after, the temple was struck by lightning. The Zeus statue graced the temple at Olympia for more than eight centuries before Christian priests persuaded the Roman emperor to close the temple in the fourth century A.D. At that time, the statue was moved to a temple in Constantinople, where it is believed to have been destroyed in a fire in the year 462.


Temple of Artemis at Ephesus


There was actually more than one Temple of Artemis: A series of several altars and temples was destroyed and then restored on the same site in Ephesus, a Greek port city on the west coast of modern-day Turkey. The most fabulous of these structures were two marble temples built around 550 B.C. and 350 B.C., respectively. The former was designed by the Cretan architect Chersiphron and his son Metagenes and decorated by some of the most celebrated artists of the ancient world. The building burned on July 21, 356 B.C., according to legend the same night that Alexander the Great was born. About six years later, the building of a new temple to replace it was begun. The new building was surrounded by marble steps that led to a more than 400-foot-long terrace. Inside stood 127 60-foot marble columns and a statue of Artemis. Archeologists disagree as to whether the building had an open-air ceiling or was topped with wood tiles. The temple was largely destroyed by Ostrogoths in A.D. 262, and it was not until the 1860s that archeologists dug up the first of the ruins of the temple’s columns at the bottom of the Cayster River.

Mausoleum at Halicarnassus


Located in what is now southeastern Turkey, the Mausoleum at Halicarnassus was a tomb built by Artemisia for her husband, Mausolus, the king of Carnia in Asia Minor, after his death in 353 B.C. Mausolus was also Artemisia’s brother, and, according to legend, she was so grief-stricken at his passing that she mixed his ashes with water and drank them in addition to ordering the mausoleum’s construction. The massive mausoleum was made entirely of white marble and is thought to have been about 135 feet high. The building’s complicated design, consisting of three rectangular layers, may have been an attempt to reconcile Lycian, Greek and Egyptian architectural styles. The first layer was a 60-foot base of steps, followed by a middle layer of 36 Ionic columns and a stepped, pyramid-shaped roof. At the very top of the roof lay the tomb, decorated by the work of four sculptors, and a 20-foot marble rendition of a four-horse chariot. The mausoleum was largely destroyed in an earthquake in the 13th century and its remains were later used in the fortification of a castle. In 1846, pieces of one of the mausoleum’s friezes were extracted from the castle and now reside, along with other relics from the Halicarnassus site, in London’s British Museum.

Colossus of Rhodes


The Colossus was an enormous bronze sculpture of the sun god Helios built by the Rhodians over 12 years in the third century B.C. The city was the target of a Macedonian siege early in the fourth century B.C. and, according to legend, the Rhodians sold the tools and equipment left behind by the Macedonians to pay for the Colossus. Designed by the sculptor Chares, the statue was, at 100 feet, the tallest of the ancient world. It was completed around 280 B.C. and stood for sixty years until it was toppled in an earthquake. It was never rebuilt. Hundreds of years later, Arabs invaded Rhodes and sold the remains of the statue as scrap metal. Because of this, archeologists do not know much about the exact location of the statue or what it looked like. Most believe that it depicted the sun god standing naked while he lifted a torch with one hand and held a spear in the other. It was once believed that the statue stood with one leg on each side of a harbor, but most scholars now agree that the statue’s legs were most likely built close together to support its immense weight.

Lighthouse of Alexandria


The Lighthouse of Alexandria was located on a small island called Pharos near the city of Alexandria. Designed by the Greek architect Sostratos and completed around 270 B.C. during the reign of Ptolemy II, the lighthouse helped to guide Nile River ships in and out of the city’s busy harbor. Archeologists have found ancient coins on which the lighthouse was depicted, and from them deduced that the structure had three tiers: a square level at the bottom, an octagonal level in the middle and a cylindrical top. Above that stood a 16-foot statue, most likely of Ptolemy II or Alexander the Great, for whom the city was named. Although estimates of the lighthouse’s height have ranged from 200 to 600 feet, most modern scholars believe it was about 380 feet tall. The lighthouse was gradually destroyed during a series of earthquakes from 956 to 1323. Some of its remains have since been discovered at the bottom of the Nile.
Actividad N° 1
MARCA CON UNA X LAS SIETE MARAVILLAS DEL MUNDO ANTIGÜO



Actividad N°2

MÚLTIPLE OPCIÓN
1) Las pirámides de Egipto se localizan en:

a)Alexandría
b)Guiza
c) El Cairo

2) Los Jardines Colgantes de Babilonia fueron construidos cerca de:

a) el río Éufrates, en Irán
b) el río Tigris, en Irak
c) el río Éufrates, en Irak
d) el río Tigris, en Irán

3) En qué año fue destruida la estatua de Zeus:

a) 462 a.C
b) 500
c) 462
d) 500 a.C

4) De qué material estaban hechos los templos:

a) Piedra
b) Madera
c) Mármol
d) Oro

5)  Cuántos metros de altura medía aproximadamente el Mausoleo de Halicarnassus:

a) 135
b) 60
c) 1846
d) 20

6) Cuál de las siguientes maravillas está ubicada en Alejandría:

a) Las Pirámides
b) El Coliseo
c) Los Jardines Colgantes
d) El Faro

7) Quién era Helios

a) un emperador
b) el dios de los sueños
c) el dios del sol
d) un faraón


Actividad N°3



Elige a tu criterio cuáles serían las 7 maravillas del mundo actual.


martes, 25 de septiembre de 2012

Climate Change

Clara López - Francisca de Cabrera 


Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions, or in the distribution of weather around the average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors that include oceanic processes (such as oceanic circulation), variations in solar radiation received by Earth, plate tectonics and volcanic eruptions, and human-induced alterations of the natural world; these latter effects are currently causing global warming, and "climate change" is often used to describe human-specific impacts.
Scientists actively work to understand past and future climate by using observations and theoretical models. Borehole temperature profiles, ice cores, floral and faunal records, glacial and periglacial processes, stable isotope and other sediment analyses, and sea level records serve to provide a climate record that spans the geologic past. More recent data are provided by the instrumental record. Physically based general circulation models are often used in theoretical approaches to match past climate data, make future projections, and link causes and effects in climate change.

Causes
On the broadest scale, the rate at which energy is received from the sun and the rate at which it is lost to space determine the equilibrium temperature and climate of Earth. This energy is distributed around the globe by winds, ocean currents, and other mechanisms to affect the climates of different regions.
Factors that can shape climate are called climate forcings or "forcing mechanisms". These include processes such as variations in solar radiation, variations in the Earth's orbit, mountain-building and continental drift, clouds and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond slowly in reaction to climate forcings, while others respond more quickly.
Forcing mechanisms can be either "internal" or "external". Internal forcing mechanisms are natural processes within the climate system itself (e.g., the thermohaline circulation). External forcing mechanisms can be either natural (e.g., changes in solar output) or anthropogenic (e.g., increased emissions of greenhouse gases).
Whether the initial forcing mechanism is internal or external, the response of the climate system might be fast (e.g., a sudden cooling due to airborne volcanic ash reflecting sunlight), slow (e.g. thermal expansion of warming ocean water), or a combination (e.g., sudden loss of albedo in the arctic ocean as sea ice melts, followed by more gradual thermal expansion of the water). Therefore, the climate system can respond abruptly, but the full response to forcing mechanisms might not be fully developed for centuries or even longer.

PREDICCIÓN DE LOS CONCEPTOS QUE VA A TRATAR EL AUTOR

- Diferencia entre clima y tiempo atmosférico
- Causas del cambio
- Consecuencias
- Líneas de acción
- Animales en extinción

DEFINICIÓN DE CONCEPTOS DESDE NUESTRO CONOCIMIENTO

Clima: características constantes de acuerdo a una zona de insolación.

Tiempo atmosférico: depende del clima, se podría decir que son las manifestaciones del clima. Se trata de la apropiación de los factores climáticos en un momento específico.

Consecuencias: Aumento de la temperatura de los océanos.
                          Extinción de animales, cambios en los ecosistemas
                          Probabilidad de mayor catástrofes
                          Destrucción de la capa de ozono

Líneas de acción: Apuntar a la educación ambiental.
                             Campañas ambientales.
                             Disminución del consumo y aumento del cuidado de la tierra.

Animales en extinción: Tigre de bengala, oso polar, el pinguino emperador, tortuga, gato montes, corales de las zonas cálidas.


LO QUE DICE EL AUTOR

- El cambio climático es un cambio significativo y duradero de los patrones del clima.
- Es causado por diversos factores, como ser: la circulación oceánica, las variaciones en la radiación solar, la tectónica de placas, las erupciones volcánicas y las alteraciones inducidas por el hombre en el mundo natural; factores que han generando el calentamiento global. 
- Los científicos trabajan con distintos métodos para estudiar la evolución del clima y lo que se prevé para el futuro en relación al calentamiento global.

BUSCA LAS SIGUIENTES PALABRAS EN LA SOPA DE LETRAS: Atmósfera, clima, radiación, mareas, vientos, presión, ozono, cambio, temperatura, calentamiento, naturaleza, hombre.

¡Puedes encontrar palabras en vertical, horizontal, diagonal y en todos los sentidos!

A
Z
F
R
T
Y
S
P
R
E
S
I
O
N
G
F
J
H
T
P
D
E
G
I
D
R
T
I
E
V
I
E
N
T
O
S
R
F
H
O
E
N
D
O
O
Z
O
C
Z
O
R
R
E
P
M
T
N
Q
H
T
O
T
O
L
A
S
E
T
P
E
A
U
G
E
I
N
N
P
E
Z
N
R
O
T
T
C
A
M
B
I
O
D
I
S
O
E
S
A
U
I
F
P
U
H
S
E
G
F
E
F
D
T
R
T
P
E
N
O
I
C
A
I
D
A
R
M
A
U
O
R
A
S
S
A
L
A
M
M
G
O
L
V
I
A
S
T
D
E
A
I
U
U
H
S
E
N
D
T
D
R
Y
I
S
U
M
Y
I
F
Z
T
R
U
M
A
R
E
A
S
Y
A
T
E
A
D
N
R
U
Y
O
H
E
R
T
F
O
R
L
F
I
A
B
U
E
R
B
M
O
H
H
A
C
A
L
E
N
T
A
M
I
E
N
T
O
I