Chapter 7

Section 3: Science

The Science section consists of multiple-choice, fill-in-the-blank, drop-down, drag-and-drop, hot-spot, and short-answer items intended to measure general concepts in science. The questions are based on short passages that may include a graph, chart, or figure. Study the information given and then answer the question(s) following it. Refer to the information as often as necessary in answering the questions, but remember that you have a time limit, and you should try to spend as little time on any item as you can and still get the correct answer.

You havehort Answer 90 minutes to complete this section including answering a short-answer prompt, which should take about 10 minutes. The answers and explanations to this section’s questions are in Chapter 9. Go through the explanations to all the questions, even for the ones you answered correctly. The explanations are a good review of the techniques we discuss throughout the book.

Unless you require accommodations, you’ll be taking the GED test on a computer. Instead of marking your answers on a separate answer sheet, like you do for the practice test sections in this book, you’ll see clickable ovals and fill-in-the-blank text boxes, and you’ll be able to click with your mouse and drag and drop items where indicated. We formatted the questions and answer choices in this book to make them appear as similar as possible to what you’ll see on the computer-based test, but we had to retain some A, B, C, D choices for marking your answers, and we provide an answer sheet for you to do so.

Science Test

Time: 90 minutes

Directions: Read each item carefully and mark your answer on the answer sheet provided by filling in the corresponding oval or writing your answer in the blank box.

Questions 1–2 refer to the following passage.

Insulation

During the winter, you need something to keep warmth in the house and cold air out. In the summer, you need something to keep heat outside and cooler air inside. What you need is insulation.

Insulation reduces or prevents the transfer of heat (called thermal transfer) from the inside out or the outside in. Fiberglass and plastic foam provide such insulation because they contain trapped air. Normally, air is not a good insulator because the currents in air transfer the heat from one place to another. Trapping the air in small places, however, slows or prevents the transfer of heat. Think about these little packets of air the next time you sit in a warm house, safe from the frigid air of winter.

Joe J.J. Johnson, the world-famous architect and building supervisor, has developed a standard vacation home that he builds for his clients. This house has one floor-to-ceiling glass wall that overlooks the best feature of the client's lot. The other walls are cinder block covered with a cosmetic coat of concrete.

Mr. Johnson has been hired to build one of his famous designs for a client who lives in Juno, Alaska, in a huge home with a spectacular view of the Gastineau Channel. The client has requested a variation on the standard design to reduce his heating costs.

1. What variation would make the most sense to reduce the heating costs?

(A) Have a floor-to-ceiling window facing away from the channel toward the front of the property.

(B) Replace the floor-to-ceiling window with a cinder block wall.

(D) Order an oversized furnace.

2. What other ways could the homeowner consider to reduce the cost of energy to heat the house?

(A) Add as much additional insulation as possible.

(B) Use the house only during the summer months.

(D) All of the above.

Questions 3–5 refer to the following passage.

Metabolism

The process of metabolism is an essential process in every living cell. Metabolism allows the cell to obtain and distribute energy, which is necessary for survival. Light from the sun is absorbed and converted into chemical energy by photosynthesis, and it is this chemical energy that is necessary for animals to survive.

One of the primary carbohydrates derived from plants is glucose. Through a process called glycolysis, energy is obtained from glucose. This reaction takes place in mitochondria, and the glucose molecule is broken down into pyruvic acids, which are further broken down into molecules, such as ethanol and lactic acid. This process is cyclical as the energy produced keeps the fermentation going.

Pyruvic acids are broken down to carbon dioxide and water by respiration, which releases far more energy. What started out as sunlight has become through photosynthesis the energy that keeps animals alive.

3. How do animals depend on plants to stay alive?

(A) Animals need the shade provided by plants.

(B) Cures for some diseases originate in plants.

(D) Plants provide animals with chemical potential energy.

4. What would happen to a plant if you covered it with a cloth that does not allow light to pass through it?

(A) The plant would stop growing.

(B) The leaves would shrivel.

(D) The plant would starve to death.

5. The chemical that is key to providing animals with energy is 9781118899908-un0201.tif .

Questions 6–7 refer to the following passage.

Velocity and Speed

There is a difference between speed and velocity, though sometimes you see the words used interchangeably. The velocity of a body is its rate of motion in a specific direction, such as a bicycle traveling 34 miles per hour due east. Because velocity has both magnitude (34 miles per hour) and direction (due east), it can be represented by a vector.

Speed has a magnitude only. If a bicycle travels at a speed of 28 miles per hour, you know its magnitude (28 miles per hour) but not its direction. Because speed has a magnitude but not a direction, it can be represented as a scalar.

6. If force is defined as that which is required to change the state or motion of an object in magnitude and direction, how should it be represented?

(A) wavy lines

(B) straight line

(D) vector

7. A GPS is a device that shows you your position on Earth and can give you directions to get to another location on Earth. The directions given by a GPS are really in the form of 9781118899908-un0201.tif .

Questions 8–9 refer to the following diagram, which is excerpted from Physical Science: What the Technology Professional Needs to Know, by C. Lon Enloe, Elizabeth Garnett, Jonathan Miles, and Stephen Swanson (Wiley).

9781118899908-un07002.tif — ©John Wiley & Sons, Inc.

8. What properties of water and steam allow Newcomen's steam engine to operate?

(A) Water is heavier than steam.

(B) Steam condenses when cooled, occupying less space.

(D) The pump rod is heavy enough to pull the arm down.

9. What effect does the condensation of steam in the cylinder with the piston have on the pump that fills the cistern?

(A) It controls the fire in the boiler.

(B) It pumps water from the cistern to the boiler.

(D) It forces the piston down.

Question 10 refers to the following figure.

9781118899908-un07003.tif — ©John Wiley & Sons, Inc.

10. If the number of consumers in an ecosystem began to multiply without control, the result to the balance of the ecosystem would be 9781118899908-un0201.tif .

Questions 11–14 refer to the following passage.

The Big Bang Theory

It is hard enough to imagine the universe as it is now and even harder to create a theory about how it all began. In the 1940s, George Gamow began to develop such a theory. Georges Lemaitre, another scientist, had also been working on the problem, and Gamow used some of the ideas of Lemaitre to develop his theory.

Gamow proposed the following theory: Somewhere between 10 and 21 billion years ago, there was a giant explosion in space. Before the explosion, the universe was the size of an atomic nucleus, with a temperature of about 10 billion degrees. The explosion started the expansion of the universe. Quarks, or elemental particles, existed in huge numbers.

Within a millisecond, the universe had expanded to the size of a grapefruit. The temperature cooled to 1 billion degrees. The quarks began to clump into protons and neutrons. Minutes later, the universe was still too hot for electrons and protons to form into atoms: a super-hot, fog-like environment.

With passing time and cooling temperatures, nuclear reactions took place, and within 300,000 years, atoms of hydrogen and helium began to emerge. As the atoms formed, light began to shine. The universe was taking shape.

Gravity began to act on the atoms and transform them into galaxies. Within 1 billion years of that first great explosion, galaxies and stars began to form. Within 15 billion years, planets began to emerge from the heavy elements thrown off by the dying of stars. The universe started with a big bang and continues to grow and change according to this theory.

11. The temperature of the first tiny particles was thought to be 9781118899908-un0201.tif billion degrees.

12. For galaxies to have been transformed from atoms, what was necessary?

(A) heat

(B) pressure

(D) gravity

13. This theory is called the “Big Bang” because

(A) An interplanetary war created a void, which the planets were formed to fill.

(B) An immense explosion created the planets.

(D) The explosion was very loud.

14. How is the formation of hydrogen and helium atoms related to the possible destruction from an atomic bomb?

(A) Both use hydrogen.

(B) No relation exists.

(D) Both are nuclear reactions.

Questions 15–17 refer to the following passage.

The Jellyfish

One of the creatures living in all the world's oceans is the jellyfish. Although it lives in the ocean, it is not a fish. The jellyfish is an invertebrate — that is, an animal lacking a backbone. Not only does it lack a backbone, but the jellyfish also has no heart, blood, brain, or gills and is more than 95 percent water.

Around the bell-like structure of the body, the jellyfish has tentacles — long tendrils that contain stinging cells — which are used to capture prey. The movement of the prey triggers the sensory hair in the stinging cell, and the prey is then in trouble.

Unfortunately, people are also in trouble if they get too close to the tentacles of a jellyfish. The stings are not fatal to humans but can cause a great deal of discomfort.

15. Why is a jellyfish classified as an invertebrate?

(A) It has tentacles.

(B) It has a small brain.

(D) It has no backbone.

16. What are the possible consequences for a swimmer swimming in the vicinity of a school of jellyfish?

(A) They look weird.

(B) Swimmers can get caught in the tentacles.

(D) The jellyfish may sting the swimmer, and the stings are painful.

17. Why do most small ocean creatures try to avoid jellyfish?

(A) Jellyfish get in the way of the fish when they are feeding.

(B) Jellyfish sting and eat small ocean creatures.

(D) Jellyfish and ocean creatures compete for the same food sources.

Questions 18–25 refer to the following passage.

Laws of Conservation

You are faced with laws every day. You cannot speed on the roads, and you cannot park wherever you choose.

Science has its laws as well. One such law is that energy cannot be created or destroyed. This law, called the law of conservation of energy, makes sense because you cannot create something from nothing. If you have an electrical charge, you cannot simply make it disappear.

A further law of conservation is the law of conservation of matter, which says that matter cannot be created or destroyed. This means that when a chemical change occurs, the total mass of an object remains constant. When you melt an ice cube, the water that results is neither heavier nor lighter than the original ice cube.

18. Trees are damaged when struck by lightning, but the lightning is nowhere apparent afterward. Because lightning is a form of energy, what would explain the apparent disappearance of the energy in the lightning?

(A) The energy in the lightning disappears.

(B) The energy in the lightning must be conserved and is transformed into another form of energy that affects the tree.

(D) Lightning striking the tree creates new energy, which damages the tree.

19. What is the purpose of laws in science?

(A) Science is an ordered discipline, and the laws provide the requisite order.

(B) Laws set parameters within which scientists can proceed with their investigations.

(D) All of the above.

20. When a magician makes a rabbit appear in a hat, it is an example of which law of science?

(A) conservation of energy

(B) conservation of matter

(D) conservation of resources

21. When an iceberg melts as a result of temperature changes, the law of science that is being best illustrated is 9781118899908-un0201.tif .

22. When you take a dead battery out of your flashlight, what has happened to its original charge?

(A) It has been converted into light.

(B) It has disappeared.

(D) The energy has been destroyed.

23. How would a scientist categorize the result of adding 3 ounces of water to 1 ounce of salt?

(A) An example of the law of conservation of energy in that the amount of energy would be the same afterward as before.

(B) You will end up with 1 ounce of salty water.

(D) An example of the law of conservation of mass in that the total mass will remain the same.

24. A ball rolling down a hill cannot stop by itself. What law of science explains this?

(A) There is a bump on the road.

(B) The ball has no brakes.

(D) The theory of the laws of conservation keeps the ball from stopping.

25. What is the purpose of laws in science?

(A) They summarize the results of a group of experimental results in a form that can be understood and remembered.

(B) They represent the sum of positive reproducible experimental results in a coherent summary statement.

(C) They represent the mathematical or verbal summary of a series of diverse experimental results that may not otherwise be recognized as related.

(D) All of the above.

Questions 26–28 refer to the following passage.

Why Do Birds Fly South for the Winter?

Every fall, the sky is full of birds flying south for the winter. However, you can still see a few birds in the northern part of the country during the winter. Scientists have advanced theories about this phenomenon.

Some birds eat insects for food. In winter, many species of birds fly south, because that's where the food exists. In southern states, insects are available all year long, providing a banquet for the birds, whereas in the northern parts of the country, insects (as well as other food sources, such as seeds and berries) are scarce or even nonexistent during the winter. The birds fly south for winter to follow the food. In the spring, as insects once again become plentiful in the northern states, the birds still follow the food, this time to the north.

26. Why do migratory birds return to the northern states in the spring?

(A) They miss their summer homes.

(B) It gets too hot in the southern states.

(D) They fly north out of habit.

27. How is the population of insects in a geographical area related to the regular migratory pattern of birds?

(A) Insects bite the birds.

(B) The insects lead the birds south.

(D) Birds have a habit of always eating the same insects.

28. Why are scientists interested in the migration of birds?

(A) It happens regularly and apparently without reason.

(B) Scientists like to go south.

(D) Scientists look for connections between caterpillars and travel.

Questions 29–30 refer to the following passage.

The Law of Unintended Consequences

Lake Victoria is the largest freshwater lake in Africa. It once had abundant fish, which provided protein for the local people who ate the fish. Unfortunately, a new species — the Nile Perch — was introduced into the lake by fishermen looking for a challenging fishing experience to attract their share of tourists interested in exploring the area.

The Nile Perch is an aggressive predator and had no natural enemies in Lake Victoria. It quickly ate up large numbers of the smaller fish, which affected the diets of the local population. These smaller fish ate algae and parasite-bearing snails. Without the smaller fish eating them, the live algae spread over the surface of the lake. Dead algae sank to the bottom of the lake and decayed, a process that consumed oxygen necessary for the fish living deep in the lake.

The snails, without natural predators, and the parasites they carried multiplied, creating a serious health hazard to the population. The introduction of a fish to encourage tourism had a detrimental effect on the lake and the population that depended on it.

29. What human intervention caused the destruction of the ecological balance in Lake Victoria?

(A) shrinking populations of snails

(B) freshwater lake

(D) the Nile Perch

30. Why is it seldom beneficial to introduce a foreign species into a stable environment?

(A) The foreign species has plenty of predators.

(B) The other species in the lake would not have to compete for food.

(D) The foreign species can upset the ecological balance.

Questions 31–34 refer to the following table, which is adapted from Hands-On General Science Activities with Real-Life Applications, by Pam Walker and Elaine Wood (Wiley).

Space Travel

Characteristic	Moon	Mars
Distance from Earth	239,000 miles	48,600,000 miles
Gravity	1/6 Earth's gravity	1/3 Earth's gravity
Atmosphere	None	Thin carbon dioxide, 1% air pressure of Earth
Trip time	3 days	1.88 Earth years
Communication time	2.6 seconds, round trip	10 to 41 minutes, round trip

31. If you were an aeronautical engineer planning a journey to Mars, why would you prefer to go to a space station on the moon and then launch the rocket to Mars instead of going directly from Earth to Mars?

(A) Lower gravity on the moon means you need less fuel for the launch.

(B) You have more space to take off and land on the moon.

(D) The moon is closer to Earth than Mars.

32. If you were a communications engineer trying to establish a safety network to warn a rocket ship of dangers, where would you place the transmitter for this rocket ship's journey to Mars?

(A) on the moon

(B) on Earth

(D) not enough information given

33. Why would a trip to the moon be a better first choice than a trip to Mars for space travelers?

(A) You can see the moon from Earth without a telescope.

(B) The time of the trip is much shorter.

(D) There are already space vehicles on the moon.

34. If you held a pole-vaulting contest on the moon and Mars, the same contestant would vault higher with the same expenditure of energy on 9781118899908-un0201.tif .

Questions 35–37 refer to the following passage.

Heredity, Then and Now

How often have you seen a young child and said, “She takes after her parents”? Many traits in a child do come from her parents. Physical and other characteristics, such as hair color and nose shape, are transmitted from one generation to the next. These characteristics, passed from one generation to the next, exist because of genetic code.

The first scientist to experiment with heredity was Gregor Mendel during the 19th century. Mendel experimented with pea plants and noted that characteristics appearing in “child” plants were similar to the “parent” plants. Mendel hypothesized that these characteristics were carried from generation to generation by “factors.” It took many years of research to understand why children often look like their parents, but genetic code is now the basis of the study of heredity.

35. According to the passage, 9781118899908-un0201.tif is a primary determinant for characteristics of the next generation.

36. The factors that Mendel hypothesized carried traits from one generation to the next is

(A) traits

(B) protons

37. If you want to grow monster-sized pumpkins, from what kind of pumpkins do you want to get seeds to increase the probability of growing larger-than-average pumpkins?

(A) orange pumpkins

(B) monster-sized pumpkins

(D) healthy pumpkins

Questions 38–39 refer to the following passage.

The Space Shuttle

NASA has designed and built six space shuttles: Atlantis, Challenger, Columbia, Discovery, Endeavor, and Enterprise. The space shuttles are made up of two distinct parts: the orbiter and the booster rocket. The booster rocket provides the additional thrust to get the space shuttle away from the gravitational pull of the earth. The orbiter carries the people and payload as well as the workings of the shuttle. In a space flight, the booster is jettisoned after clearing the earth's gravitational pull, and the orbiter continues on its way.

38. Why would the booster be jettisoned during flight?

(A) because the shuttle needs to add weight

(B) to increase the size of the shuttle

(D) because it is no longer needed

39. Which part of a shuttle carries the payload?

(A) booster

(B) cockpit

(D) rocket

Questions 40–41 refer to the following figure, which is excerpted from Physical Science: What the Technology Professional Needs to Know, by C. Lon Enloe, Elizabeth Garnett, Jonathan Miles, and Stephen Swanson (Wiley).

9781118899908-un07004.tif — ©John Wiley & Sons, Inc.

40. Work is defined as the product of force times displacement. Consider the diagram. If the force of gravity is greater than the forces being exerted by the muscles controlling the hand, what would happen?

(A) Nothing would happen.

(B) The hand would move downward.

(D) The hand would move upward.

41. If an athlete knows that building muscles requires doing work against a weight, what would the athlete want to change in this diagram?

(A) Move the hand upward faster.

(B) Add weight to the hand.

(D) Exhale as the arm is raised.

Questions 42–43 refer to the following passage, which is adapted from The Sciences: An Integrated Approach, 3rd Edition, by James Trefil and Robert M. Hazen (Wiley).

Copying DNA Sequence

The polymerase chain reaction (PCR) copies a sequence of DNA. To do this, a strand of DNA is mixed with nucleotides (DNA precursors). Nucleotides target a specific piece of DNA, as well as polymerase, an enzyme that helps to assemble DNA. Heat is applied until the temperature reaches 200°F. The energy from the heating separates the DNA strands. The mixture is then cooled to 140°F. At this temperature, the primers attach themselves to the DNA strands. Raising the temperature to 160°F causes the nucleotides to begin to attach to the DNA strands. After all this, two copies of the DNA are created.

42. To separate the DNA strands during the polymerase chain reaction, the addition of 9781118899908-un0201.tif is necessary.

43. To clone an organism, you require an identical DNA blueprint. The PCR is something a scientist who is interested in cloning would want to study because 9781118899908-un0201.tif .

Questions 44–45 refer to the following passage.

Dogs and Wolves — Relatives?

Current scientific theory is that the familiar family pet, the dog, descended from the wolf, but the dog has taken a very different path. The dog was the first animal to be domesticated, right around the end of the Ice Age.

Dogs are part of an extended family called Canidae, which contains 38 different species. Jackals, foxes, wolves, and dogs are all part of this family. Although they are related, wolves and dogs are different. Wolves have smaller heads for the same body weight. Dogs have smaller teeth, a more curved lower jaw, and eyes that are more rounded and forward looking. At a distance, however, many of these differences are difficult to spot.

44. What feature makes the wolf better adapted to hunting in the wild?

(A) heavier coat

(B) larger body

(D) larger paws

45. What attribute of dogs makes them a better household pet than other members of the Canidae family?

(A) There are many types of dogs to choose from.

(B) Dogs were domesticated.

(D) Dogs can help the visually impaired.

Questions 46–48 refer to the following passage.

Isotopes

Isotopes are chemical cousins. They are related to each other, but each isotope has slightly different — but related — atoms. Each of the related atoms has the same number of protons but a different number of neutrons. Because the number of electrons or protons determines the atomic number, isotopes have the same atomic number.

The number of neutrons determines the mass number. Because the number of neutrons in each isotope is different, the mass number is also different. These cousins all have different mass numbers but the same atomic number. Their chemical properties are similar but not the same. Like most cousins, they have family resemblances, but each has a unique personality.

46. Different elements would have different numbers of 9781118899908-un0201.tif .

47. Isotopes of a chemical have the same

(A) number of neutrons

(B) mass number

48. A scientist has found related atoms in two different substances. If both atoms have the same atomic number but different mass numbers, what preliminary conclusion can be reached about the atoms?

(A) They are the same substance.

(B) They are isotopes.

(D) One is a compound of the other.

Questions 49–50 refer to the following passage.

How to Survive the Winter

When the temperature drops and the wind blows cold, you may think of animals that don't have homes to keep out the cold and worry about their ability to survive the winter. Not much food is available, temperatures in northern states go into the sub-zero range, and shelter is limited. How do they survive the winter?

Many animals can find shelter and hibernate for the winter. Hibernation is a sleeplike condition in which the animal's heartbeat, temperature, and metabolism slow down to adapt to the colder temperatures. This dormant condition prevents their starving or freezing during the harsh winters.

49. To survive the winter, bears do what?

(A) Live in warm caves.

(B) Grow heavy winter coat.

(D) Find a safe shelter and hibernate.

50. Why should you not disturb a hibernating animal?

(A) It gets grouchy when awakened suddenly.

(B) It could have trouble falling asleep again.

(D) It would not be able to find enough food to survive.

Short Answer

Passage

Everyone is familiar with cheddar cheese. People put it in sandwiches, on top of hamburgers, and eat it as a snack. People seem to like its orange color and slightly sharp taste, but what if they were served a slice of this common cheese with white specks on its surface? Then they might decide on another type of cheese for their next snack or sandwich. The local hamburger emporium may decide to substitute Swiss cheese for cheddar on its burgers to reduce complaints. These white spots present a problem.

The white spots are a substance called calcium lactate crystals and develop most often on the surfaces of naturally smoked cheddar cheese. Producers are very much aware of the problems caused by calcium lactate crystals as you can tell by the fact that naturally smoked cheddar cheese is more expensive than the everyday processed cheddar, and it's considered more of a gourmet item. Customers who pay more for what they believe is a better, more natural product do not appreciate white spots on the surface of their purchase. The other problem facing retailers and wholesalers of naturally smoked cheddar is that the amount of calcium lactate crystals increases with time and what may appear to be clear of the problem one day could look very different with the passage of time.

Food scientists have been studying these white spots because they cause a problem for sellers of this product. Scientists have investigated chemical changes that may or may not occur during natural smoking that could produce this unwanted substance. In order to proceed with this study, scientists took a large block of cheddar and cut out two equal and equivalent blocks of cheese. They smoked one block in a commercial smokehouse and stored the other without smoking. After two days, they analyzed the samples for moisture, lactate, pH, and water-soluble calcium.

The results proved to be interesting. The smoked sample contained significantly lower moisture and a lower pH level. There was a higher total lactate-in-moisture and water-soluble calcium-in-moisture level at the surface of the samples. After a period of ten weeks, there were some changes in the levels with the pH, total lactate-in-moisture and water-soluble calcium-in-moisture levels remaining constant. It was concluded that the smoking process predisposes the cheddar to surface calcium lactate crystal formation.

Prompt

Why would a scientist be interested in white specks on cheddar cheese and how did the results of the experiment help in solving the problem? Write your answer in the space provided. This task may require approximately 10 minutes to complete.