from “If These Airplanes Could Talk”
History of Aviation
1.For many thousands of years, man has looked at the sky and dreamt of flying. Evidence of this can be found in stories such as “Daedalus” from Greek mythology and “Pushpaka Vimana of Ravana” in Hindu mythology. The earliest known attempts to fly were made by fashioning wings, modeled after birds’ wings and strapping them to human arms. This method was unsuccessful but it did not deter people from continuing to attempt to fly.
2.The kite was the first successful unmanned flying device and was invented in China around 400 BC. Kites work by generating lift, just as today’s modern airplanes do. Devices that use this type of technology are referred to as “heavier-than-air” aircraft.
3. About 100 years later in 300 BC, the Chinese invented the Kongming lantern (Img. 1). Kongming lanterns (also called paper lanterns) were constructed of a thin paper shell with a lamp or candle burning underneath. The heat from the lamp warmed the air in the bag which caused the lantern to rise. The Montgolfier Brothers expanded on this discovery in 1782 and built the world’s first hot air balloon, which works according to the same principles only on a larger scale.
4.Kongming lanterns and hot air balloons both fly because gases, including air, become less dense when heated. The heated air in the balloon is lighter than the cooler, denser air outside of the balloon, and is therefore able to rise. Devices that use this technology are classified as “lighter-than-air” aircraft.
5. Throughout the centuries, people around the world studied flight and developed many different kinds of flying devices, including gliders made of lightweight wood, and airships, such as the Macon Airship (Img. 2). In 1485, Leonardo da Vinci designed a hang glider, called The Ornithopter, with fixed wings and some movable control surfaces. Although he never built the device, his design provided the basis for the modern day helicopter. During the early 19th century, several men made “flying machines” which used various technologies to power their aircraft, including electricity and steam.
6. It wasn’t until the early 20th Century that flight as we know it today emerged. Aircraft began to be made of aluminum instead of wood and fabric. Aviators experimented with several types of wing structures, including monoplane, which means “one set of wings”, biplane, and triplane (Img.3). As they refined their designs, monoplanes were made with various wing designs and many control surfaces (ailerons, elevator, rudder, etc.; see Figure 1) were added and modified.
7. In the years since the Wright Brothers’ first flight in a controlled, engine-powered aircraft, the distances we have been able to fly have increased dramatically, from the 120 feet of Orville and Wilbur’s Wright Flyer, to several thousand miles. By 1969 aircraft were taking man to the moon and today’s longest-range passenger airplanes can fly half way around the world non-stop. Aircraft Identification
8. Every aircraft has a story. You can tell a lot about an aircraft by looking at the markings and inscriptions located on the fuselage and wings. Civilian aircraft have an alphanumeric registration number (Img. 4), which is similar to the license plate on an automobile. The alphanumeric markings for aircraft registered in the United States begin with the letter “N”. They are referred to as “tail numbers” because they are usually displayed on the tail of the aircraft, although older aircraft had them displayed on the underside of the wing so they could be read by someone on the ground whilst the aircraft was in flight.
9. Military aircraft also have insignia on the fuselage, wings, or tail. This insignia identifies the nation or air force to which the aircraft belongs (Img. 5). Many military planes also have identification numbers similar to civilian aircraft. The first of such markings appeared in 1913.
1. Which quotation serves as an objective summary of the passage?
A) “For many thousands of years, man has looked at the sky and dreamt of flying.” (paragraph 1)
B) “Throughout the centuries, people around the world studied flight and developed many different kinds of flying devices, including gliders made of lightweight wood, and airships.” (paragraph 5)
C) “In the years since the Wright Brothers’ first flight in a controlled, engine-powered aircraft, the distances we have been able to fly have increased dramatically, from the 120 feet of Orville and Wilbur’s Wright Flyer, to several thousand miles.” (paragraph 7)
D)”Every aircraft has a story.” (paragraph 8)
2. Part A
How did Leonardo da Vinci influence modern-day flight?
A)by inspiring the creation of future devices
B)by owning a futuristic flight device
C)by his failure to power an aircraft
D)by his access to advanced technology
3. Part B
Which quotation from paragraph 5 provides evidence of the answer from Part A?
A)”Throughout the centuries, people around the world studied flight and developed many different kinds of flying devices, including gliders made of lightweight wood, and airships.”
B)”In 1485, Leonardo da Vinci designed a hang glider, called The Ornithopter, with fixed wings and some movable control surfaces.”
C)”Although he never built the device, his design provided the basis for the modern day helicopter.”
D)”During the early 19th century, several men made ‘flying machines’ which used various technologies to power their aircraft, including electricity and steam.”
4. Part A
In the passage, how does the author develop the central idea that the appearances of military and civilian aircrafts are similar?
A)by describing the likeness of their cockpits
B)by highlighting their comparable materials
C)by illustrating how both types are easily recognizable
D)by showcasing how both share identical wings
5.Part B
Which quotation from paragraphs 8-9 supports the answer from Part A?
A)”Every aircraft has a story.” (paragraph 8)
B) You can tell a lot about an aircraft by looking at the markings and inscriptions located on the fuselage and wings.” (paragraph 8)C) “Many military planes also have identification numbers similar to civilian aircraft.” (paragraph 9)
D) “The first of such markings appeared in 1913” (paragraph 9)
“Atoms, Elements, and Isotopes” published by NASA
- An atom is the basic structure from which all matter is composed, in the same manner as a brick is the basic structure from which a wall is built. Although atoms are too small to be seen with our eyes, scientists have long had indirect evidence for the existence of atoms. We can now use the world’s most powerful scanning tunneling microscopes to “see” the magnified images of atoms and to study surface reaction sites on an atom-by-atom basis.
- Atoms are made of small particles called protons, neutrons, and electrons. Each of these particles is described in terms of measurable properties, including mass and charge. Mass is the amount of matter that an object contains. The proton and neutron have roughly the same mass and have approximately one thousand times the mass of the electron. The proton and electron have equal, but opposite, electrical charges. A neutron does not have an electrical charge.
- In an atom, the protons and neutrons clump together in the center and are called the nucleus. Because the protons are positively charged, the nucleus has a positive electric charge. The electrons of the atom move rapidly around the nucleus. If we attempt to detect an electron in an atom, we might find evidence of it located almost anywhere around the nucleus. However, if we repeat this experiment many times, it will be found that the electron is much more likely to be located in certain regions of space surrounding the nucleus than in other regions of space. We might think that the electron is rapidly moving around the nucleus and our experiment “catches” the electron as an instantaneous “snapshot” of it in motion. The probability of finding the electron in any region of space can then be described by a cloud that rapidly thins out as one goes farther from the nucleus. The density of the cloud at any point is the probability of finding the electron at that point.
- The attractive electric force between the positively-charged protons in the nucleus and the negatively-charged electrons around the nucleus holds the atom together. Atoms containing the same number of protons and electrons have no net charge. Atoms that have extra electrons or are missing electrons have a net electrical charge and are called ions. Ions can interact with other ions due to the electrical attraction between opposite charges.
- Atoms interact with other atoms by sharing or transferring electrons that are farthest from the nucleus. These electrons are sometimes called valence electrons. These outer electrons determine the chemical properties of the element, such as how readily it interacts with other elements and the allowable ratios for its combinations with other substances.
- An element is a substance made up of a single type of atom. It can’t be broken into simpler components by chemical processes. There are 92 naturally occurring elements. They may be solids,liquids, or gases.
- The elements are distributed unevenly, with some much more common than others. The ten most abundant elements of the earth’s crust make up more than 99% of our planet.
- The mass of an atom or particle is expressed in atomic mass units or amus. One atomic mass unit is a very small amount of mass. An amu is 1/12 the mass of one atom of 12C, or about 1.66 x 10-27 kg.
- Atomic mass values for elements are almost never an integer. The only exception is carbon, whose mass was used as a standard reference. The mass of a 12C carbon atom is specified as exactly 12. The mass of an atom of another element is the ratio of its mass to the mass of a carbon atom. Even the masses of protons, neutrons, and electrons are ratios of their mass to carbon. These ratios are not integers. Since atoms are made of various numbers of these particles, it is unlikely that the mass of anatom other than carbon would add up to exactly a whole number.
- When an element has atoms that differ in the number of neutrons in the nuclei, these atoms are called different isotopes of the element. All isotopes of one element have identical chemical properties. This means it is difficult to separate isotopes from each other by chemical processes. However, the physical properties of the isotopes, such as their masses, bpoints, and freezing points, are different. Isotopes can be most easily separated from each other using physical processes.
- Most atoms of the element hydrogen contain only one proton in their nuclei. Each of these atoms has a mass of 1.008 amu. There exist atoms of hydrogen that have either one or two neutrons in the nucleus in addition to the single proton. These are called deuterium or tritium, having masses of 2.014 amu and 3.016 amu respectively. Deuterium and tritium are isotopes of hydrogen. An atom of deuterium has two particles in its nucleus, and tritium has three. Since atoms of both deuterium and tritium have only one proton in their nuclei, they only have one electron. They behave, chemically, like other hydrogen atoms.
- The sum of the number of protons and neutrons in the nucleus of an atom is called that element’s mass number. This is not the same as the element’s mass. Since different isotopes of an element contain different numbers of neutrons in the nuclel of their atoms, isotopes of the same element will have different atomic masses. This was shown above for the three isotopes of hydrogen. The symbol for an Isotope is the symbol for the element followed by the mass number. Hydrogen is symbolized as H1, while deuterium is symbolized as H2.
- What would we call an atom that had three particles in its nucleus, like tritium, but two were protons and one was a neutron? This would be an uncommon isotope of a different element, helium (He3). Because there were two protons in this nucleus, there would also be two electrons in the probability cloud around it. Since it is the outer electrons that determine the chemical properties of an atom, this would be a different kind of atom than hydrogen. The presence of two rather than one electron would cause it to have distinctive chemical properties. Thus, this must be a different element, and it is named helium. The most common isotope of helium (He4) has two protons and two neutrons in the nucleus of each atom Because there were two protons in this nudeus, there would also be two electrons in the probability cloud around it. Since it is the outer electrons that determine the chemical properties of an atom, this would be a different kind of atom than hydrogen. The presence of two rather than one electron would cause it to have distinctive chemical properties. Thus, this must be a different element, and it is named helium. The most common isotope of helium (He4) has two protons and two neutrons in the nucleus of each atom.
- To distinguish between elements, we often refer to their atomic numbers. The atomic number is the number of protons in the nucleus of an atom of that element (which is equal to the number of electrons around that atom’s nudeus). Hydrogen’s atomic number is 1, while helium’s atomic number is 2. Gold has an atomic number of 79, which means it has 79 protons in its nucleus. The modern periodic table of the elements shows the different elements arranged in increasing order of atomic number.
- There are 92 elements found in nature and several more exotic, manmade elements. Based on their chemical and physical properties, scientists have invented a tool to show relationships among these elements. It is known as the periodic table of the elements.
- Observations show that the same elements exist throughout the known universe. We organize information about the elements in the form of a periodic table. The elements and their interactions are studied in all disciplines of science, as chemicals form the basis of life science, physical science, and earth and space science. As the American Association for the Advancement of Science wrote in their Project 2061, “Science for All Americans” publication, “All humans should participate in the pleasure of coming to know their universe better.”
6. Part A
What statement is a central idea in paragraph 2?
A)Neutrons have as much influence over an atom as protons and electrons do.
B)Protons have more mass than neutrons because of their positive charges.
C)Electrons weigh more than both protons and neutrons combined.
D)Protons and electrons have electrical charges which oppose each other.
7. Part B
Which quotation supports the answer in Part A?
A) “In an atom, the protons and neutrons clump together in the center and are called the nucleus.” (paragraph 3)
B) “The attractive electric force between the positively-charged protons in the nucleus and the negatively-charged electrons around the nucleus holds the atom together.” (paragraph 4)
C) “Atoms containing the same number of protons and electrons have no net charge.” (paragraph 4)
D) “Atoms interact with other atoms by sharing or transferring electrons that are farthest from the nucleus.” (paragraph 5)
8. Part A
Which statement is a central idea of the passage?
A)Giant pandas are independent and resourceful creatures.
B) Giant pandas thrive best in tropical and wet environments.
C) Giant pandas struggle with adapting to new habitats.
D)Giant pandas are viewed as symbols of misfortune in China.
9. Part B
Select two details from the passage that best support the answer to Part A.
A) “Like many bears, giant pandas can climb trees to escape danger or for a quick nap, and they are particularly adept at climbing when young.” (paragraph 2)
B) “Giant pandas live alone except when breeding.” (paragraph 4)
C) “When cubs are born they are blind and very small which makes it difficult for the mother to protect them.” (paragraph 4)
D) “They are threatened by continued loss of habitat and by a very low birthrate.” (paragraph 5)
E) “Today, giant panda bears are relatively safe from the guns of the hunters due to the
F) remote and almost inaccessible Himalayan habitat in which they live and the protection provided by the Chinese government.” (paragraph 5)
g) “Its image appears on a large number of modern Chinese commemorative silver, gold, and platinum coins.” (paragraph 6)
10. Select three statements that should be included in an objective summary.
A)The giant panda is popular among young children.
B) Poachers have threatened giant pandas for centuries.
C) A large part of a giant panda’s diet is bamboo.
D)Giant panda cubs leave their mothers when they are six months old.
E) The population of giant pandas increases every year.
F)Giant pandas do not hibernate.
