GED Science Practice - dummies

# GED Science Practice

The Science portion of the GED consists of a series of items intended to measure general concepts in science. The items are based on short readings that may include a graph, chart, or figure. Study the information given and then answer the question(s) following it.

## Sample questions

These questions are similar to the type of questions you will encounter on the GED.

### Passage A

Questions 1–2 refer to the following diagram and excerpt from NASA’s Glenn Research Center website for Space Flight Systems.

Credit: Illustration courtesy of NASA

Many differences exist between the forces acting on a rocket and those acting on an airplane.

• On an airplane, the lift force (the aerodynamic force perpendicular to the flight direction) is used to overcome the weight. On a rocket, thrust is used in opposition to weight. On many rockets, lift is used to stabilize and control the direction of flight.

• On an airplane, most of the aerodynamic forces are generated by the wings and the tail surfaces. For a rocket, the aerodynamic forces are generated by the fins, nose cone, and body tube. For both airplane and rocket, the aerodynamic forces act through the center of pressure (the dot with the black center) while the weight acts through the center of gravity (the solid dot).

• While most airplanes have a high lift to drag ratio, the drag of a rocket is usually much greater than the lift.

• While the magnitude and direction of the forces remain fairly constant for an airplane, the magnitude and direction of the forces acting on a rocket change dramatically during a typical flight.

1. In the diagram, which force must be the greatest for the rocket to leave the earth?

• (A) drag

• (B) lift

• (C) thrust

• (D) weight

2. Short Answer Prompt: Although the purpose of both rockets and airplanes is to lift people and payloads off the earth, because of the differences in distances traveled and the medium through which they travel, explain how the forces acting on each and propelling each are different.

Write your response on a separate sheet of paper. This task may require approximately ten minutes to complete.

### Passage B

Questions 1 and 2 refer to the following excerpt from the U.S. Environmental Protection Agency’s website on climate change.

As temperatures increase, the habitat ranges of many North American species are moving northward in latitude and upward in elevation. While this means a range expansion for some species, for others it means a range reduction or a movement into less hospitable habitat or increased competition. Some species have nowhere to go because they are already at the northern or upper limit of their habitat.

For example, boreal forests are invading tundra, reducing habitat for the many unique species that depend on the tundra ecosystem, such as caribou, arctic fox, and snowy owl. Other observed changes in the United States include expanding oak-hickory forests, contracting maple-beech forests, and disappearing spruce-fir forests.

As rivers and streams warm, warmwater fish are expanding into areas previously inhabited by coldwater species. Coldwater fish, including many highly valued trout species, are losing their habitats. As waters warm, the area of feasible, cooler habitats to which species can migrate is reduced. Range shifts disturb the current state of the ecosystem and can limit opportunities for fishing and hunting.

1. As temperatures become warmer and ranges move, the new territory may prove to be less _______ for specific species.

2. When warmwater fish move into territories previously occupied by coldwater species, this creates problems for human beings because

• (A) humans depend on fish as a source of protein

• (B) fishing is a sport that aids local economies

• (C) many coldwater fish are valued as food or prey

• (D) all of the above

### Passage A

1. C. thrust.

2. The following is a sample of a Short Answer response:

You wouldn’t use a rocket to fly to Las Angeles from Washington, and you couldn’t use an airplane to fly to the moon. Although each is a method of lifting people and payload off the surface of the earth, each is a specialized form of transportation designed for a specific purpose.

An airplane is designed to carry people and payloads through the atmosphere in close proximity to the earth in relative comfort. Since the amount of lift needs to be greater than the weight of the aircraft, passengers and payload, modern jet engines can provide the necessary propulsion to move the aircraft forward while the wings provide the lift to enable the airplane to move above the surface of the earth.

Airplanes move through the air, albeit thinner air than is found near the ground, it is still able to provide the lift needed. With the advance in current technology of engines, there is enough power to provide a high degree of creature comforts for a large group of passengers.

Rockets are designed to travel through space across great distances and carry few passengers. Without the lift provided by the wings moving through the air, rockets look different. They have tiny wings relative to their size. Since so much thrust is necessary to escape the pull of the earth’s gravity, a rocket engine is huge in comparison to the ones on an airplane.

Huge rocket engines require massive amounts of fuel, and since there are no refueling stations in space, all the fuel for the return trip has to be carried upon launch. Not being commercial modes of transportation, yet, rockets do not have to be designed to carry many passengers in relative comfort.

The rocket engines provide the thrust required to lift the weight of the rocket and contents through space and back transporting fuel and what else is needed to carry out the purpose of the voyage.

### Passage B

1. hospitable.

2. D. all of the above.