VSTEP Reading Mock Test 11

The Earth is known as the Blue Planet because of its color when viewed from space by our astronauts. We enjoy sunny days when the sky is blue but it seems to be a “mystery” why the sky and atmosphere appear blue. But it’s really a matter of how the human eye works and how light interacts with air molecules in the atmosphere. Remember that humans can see visible light, those wavelengths between 400 nanometers and 700 nanometers. Visible light is divided into colors also by wavelength and this is called the color spectrum. The blue range that includes violet has the shortest wavelengths of any visible light.

When light interacts with any kind of molecules, its energy can be absorbed, reflected or scattered. Light is scattered when it hits gases in the atmosphere. The amount of light that is scattered is related to the size of the particle compared to the wavelength of the light falling on the particle. Since blue and violet have the shortest wavelength they are scattered the most by molecules of gases in the atmosphere. Because of this scattering there is more of the blue wavelength in the atmosphere than any other. The human eye has cones dedicated to receiving blue wavelength, so we see the sky as blue without noticing the traces of purple.

Another “mystery” of nature is how rainbows are formed. Rainbows are seen only after it rains and the atmosphere contains water droplets. Sunlight enters the water droplets, is bent by the droplet and is reflected out of the droplet. The different colors are bent by an amount related to their wavelength so the result is a spectrum like that produced by a prism.

A rainbow always appears as the same kind of arc in the sky. The red part of the rainbow is always at 42° to the line of the horizon and the blue-violet part of the rainbow is always at 40° with the other colors of the spectrum in between. These angles are related to the wavelength of each color. Most people have never noticed that the sun is always behind them when they face a rainbow.

Microorganisms, or microbes, are organisms that are too small to be seen by the human eye. Microbes can be fungi, bacteria, archaea, or protists, but not viruses and prions, which are commonly categorized as non-living. They are usually single-celled, or unicellular. However, there are exceptions, as some multi-cellular varieties are microscopic and some unicellular protists are visible.

Microbes can live almost anywhere on Earth where there is water. Although incredibly small, they play an important role in keeping the planet running, carrying out 90% of the Earth’s biochemical reactions. Without them, life on Earth would be destroyed. The microbes are probably the first forms of life to develop on Earth.

Microbes that live and prosper underground in high temperatures are called “thermopiles.” Dr. Bang, a microbiology professor, said that since scientists are aware that microbes existed underground, they know that the introduction of outside people, materials, and animals would have interacted with those otherwise inaccessible microbes. This interaction may have caused an evolutionary metamorphosis that went unnoticed by the world.

Scientists are indentifying factors that establish why microbes survive deep underground in some places but not others. High temperatures make certain that nothing can live too far underground. However, the availability of water, pressure, the porosity of the adjacent rock, and the flow of chemical nutrients may limit where microbes that savor harsh conditions can exist. Temperature is the primary factor in controlling how deep they can live. A lack of water and nutrients excludes subsurface life in arid regions. On the contrary, they may be more abundant deep in mid ocean ridges and salt deposits where nutrients and water flow more generously.

Rock deep underground may have scorching temperatures and toxic chemicals, but life can still survive. For example, in the early 1990’s, researchers found microbes living in rock 500 meters below the surface. More recently they have delved much deeper, nearly 3 km below ground. Tests for microbial residents and a new species of bacteria were conducted by scientists. Unfortunately, these tests cause pollution from the lubricating fluids that drillers pump into the hole. Tests on these fluids revealed a great quantity of aerobic microbes which require oxygen to survive.

In another test, scientists added a range of tracers to the drilling fluids. By checking rock samples of these man-made chemicals, they could recognize which pieces had been polluted by the drilling fluids. Finally, they measured the rock samples. The polluted type had rather large pores that allowed drilling fluid to enter the rock. Those not polluted had barred any microbes from penetrating the rock. If bacteria could not get in the rock, they also could not leave. The tight-spaced mineral grains served as cages, trapping any original bacteria for millions of years.

The organisms survive on a diet of petroleum and other organic compounds. However, because these food sources are so diluted, the microorganisms do not receive enough nutrients to grow, reproduce, or even spread throughout the rock formation. The deepest hole will introduce really high temperatures, where a lot of different biophil bacteria and water seepage reside.

Scientists recently discovered microbes living within igneous formations. These microbes are unique, relying on hydrogen, water, and carbon dioxide. Until this discovery, it was thought that products of the Earth’s interior, and other organisms to some extent, depend on the sun’s energy. Scientists in Sweden have since found a similar community of microbes deep in granite formation. These findings are of great importance because granite is one of the most abundant rocks on the continent, suggesting that these organisms are quite prevalent. Rough calculations propose that bacteria and archaea may go as deep as 4 km below the continental crust and 7 km into the oceanic crust. It has been calculated that the weight of all subterranean microbes could equal that of life above the surface.

Questions and concerns are driving investigators to explore new environments like South African gold mines. Tests on the mines reveal that bacteria survives even as deep as 3.5 km. Microbes living in high temperatures might have the potential to produce antibiotics which can be temperature tolerant. Life underground may also help solve toxic waste problems and improve methods for cleaning wastewater. The most practical application is its effect on the ethanol industry, as it can make the production process more efficient.

The Roman advanced unique principles of architecture in many ways, constructing buildings and monuments involving both engineering and architectural skill. The arch was applied to various works of utility, making it a universal feature in civil buildings. Examples of this include the Pantheon, and the Temple of Peace, both of which extended the principles of the arch to their logical limits. Both these edifices indicated the progress of the Romans toward the invention of a design that was distinctively their own.

The first Roman architects were priests because the religious leaders wanted a place to worship. Romans learned most of their architectural techniques from the Greeks and the Etruscans. Arches were used for their great support capabilities and their power to glorify. The idea of extending the arch led to the development of the dome. Cement was added to the arch construction, allowing the Romans to expand buildings. The Coliseum, for example, was built using the arch system and concrete. The other primary use of the arch was to build aqueducts, which carried water from the hills to big tanks in the cities. They held pipes lined with cement on the top of the arches which carried the water.

Arches were also built in homage to the achievements of emperors. Rome contains arches for Constantine, Titus, and many more, and all were decorated with sculptured pictures. Roman architecture was about creating a beautiful structure. It attempted to serve a function and be beautiful. For example, the Notre Dame and the Pantheon were both clearly designed to create beauty. Roman architecture emphasized symmetry and weight, which involved the use of load-bearing masonry. Detail was of immense importance, and perfection came from a meticulous and firm use of symmetrical geometries, as well as the precise implementation of proportion.

Modern buildings, since the 19th century, started to use a functional approach to design. Iron, steel, and glass enabled architects to enclose vast spaces of department stores, or market halls. Modern architecture was being inspired by abstract paintings and sculptures, and architects began to consider space and light in their designs.

Modern architecture emphasized dynamic composition, movement, and thinness by using materials such as iron and glass. Buildings were constructed using frame and cladding techniques, where a steel frame was erected and glass panes were inserted to complete the building. All loads were transferred down using the frame of the buildings. Although load-bearing materials such as brick appear to be used, virtually all of them are made of concrete and steel, with a thin layer of brick applied to the exterior to hide the true nature of the structure underneath.

The Louvre in Paris is an example of a building that has been modernized architecturally. The original style of museum has been updated to include glass and steel. Originally, the entrance to the museum attempted to create a beautiful environment in which the objects of value could be put on view. However, the new entrance attempts to bring the inside to the outside and plays with the idea of not separating the two.

There are many distinguishing features between old and modern architecture. Classical buildings, it seems, are built for longevity, as most have withstood the ages. Ancient builders used stone, mud-brick, and, eventually, wood and concrete in their buildings. Now, architectures are incorporating style and function into modern designs. Although they are not built to withstand the ages, some are works of admiration and intricate details.

[A] The production of steel, iron, concrete and aluminum has greatly extended the scale of designs that can be successfully built. [B] Today, lightweight materials allow designers to cover distances far beyond, without the use of any arches. In this day and age, functionality is important when designing a building as rooms are planned to maximize the use of space. However, in ancient times, space was not a problem. [C] Aesthetics were much more important than function. Modern and classical architecture refer to specific movements in their respective times. Both, however, share an attitude of perfectionism. [D]