SCIENCE REASONING TEST 18 Minutes — 18 Questions pps

4 ● ● ● ● ● ● 4Passage II While the focus point of origin of most earthquakes lies less than 20 km below the Earth’s surface, certain unusual seismographic readings indicate that some ac

4 ● ● ● ● ● ● 4

SCIENCE REASONING TEST

18 Minutes — 18 Questions

Directions: There are three passages in this test Each

passage is followed by several questions After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer sheet You may refer to the passages as often as necessary

Passage I

A series of experiments was performed to study the

environmental factors affecting the size and number of

leaves on the Cyas plant.

Experiment 1

Five groups of 25 Cyas seedlings, all from 2–3 cm

tall, were allowed to grow for 3 months, each group at a

different humidity level All of the groups were kept at 75°

F and received 9 hours of sunlight a day The average leaf

lengths, widths, and densities are given in Table 1

Table 1

%

Humidity

Average length (cm)

Average width (cm)

Average density*

(leaves/cm) 15

35

55

75

95

5.6 7.1 9.8 14.6 7.5

1.6 1.8 2.0 2.6 1.7

0.13 0.25 0.56 0.61 0.52

*Number of leaves per 1 cm of plant stalk

Experiment 2

Five new groups of 25 seedlings, all from 2–3 cm tall,

were allowed to grow for 3 months, each group receiving

different amounts of sunlight at a constant humidity of

55% All other conditions were the same as in Experiment

1 The results are listed in Table 2

Table 2

Sunlight (hrs./day)

Average length (cm)

Average width (cm)

Average density*

(leaves/cm) 0

3 6 9 12

5.3 12.4 11.2 8.4 7.7

1.5 2.4 2.0 1.8 1.7

0.32 0.59 0.56 0.26 0.19

*Number of leaves per 1 cm of plant stalk

Experiment 3

Five new groups of 25 seedlings, as above, were allowed to grow at a constant humidity of 55% for 3 months at different daytime and nighttime temperatures All other conditions were the same as in Experiment 1 The results are shown in the following table

Table 3

Day/Night Temperature (˚F)

Average length (cm)

Average width (cm)

Average density*

(leaves/cm) 85/85

85/65 65/85 75/75 65/65

6.8 12.3 8.1 7.1 8.3

1.5 2.1 1.7 1.9 1.7

0.28 0.53 0.33 0.45 0.39

*Number of leaves per 1 cm of plant stalk

4 ● ● ● ● ● ● 4

1. Which of the following conclusions can be made

based on the results of Experiment 2 alone?

A The seedlings do not require long daily periods of

sunlight

B The average leaf density is independent of the

humidity the seedlings receive

C The seedlings need more water at night than during

the day

D The average length of the leaves increases as the

amount of sunlight increases

2. Seedlings grown at a 40% humidity level under the

same conditions as in Experiment 1 would have

average leaf widths closest to:

F. 1.6 cm

G 1.9 cm.

H 2.2 cm.

J. 2.5 cm

3. According to the experimental results, under which

set of conditions would a Cyas seedling be most

likely to produce the largest leaves?

A 95% humidity and 3 hours of sunlight

B 75% humidity and 3 hours of sunlight

C 95% humidity and 6 hours of sunlight

D 75% humidity and 6 hours of sunlight

4. According to the results given, Cyas plants are

LEAST likely to flourish:

F. in deserts

G in temperate grasslands.

H in tropical jungles.

J. at high altitudes

5. It was assumed in the design of the 3 experiments

that all of the Cyas seedlings were:

A more than 5 cm tall.

B equally capable of germinating.

C equally capable of producing flowers.

D equally capable of further growth.

6. As a continuation of the 3 experiments listed, it would

be appropriate to next investigate:

F. how many leaves over 6.0 cm long there are on each plant

G which animals consume Cyas seedlings.

H how the mineral content of the soil affects the leaf

size and density

J. what time of year the seedlings have the darkest coloring

4 ● ● ● ● ● ● 4

Passage II

While the focus (point of origin) of most earthquakes

lies less than 20 km below the Earth’s surface, certain

unusual seismographic readings indicate that some activity

originates at considerably greater depths Below, two

scientists discuss the possible causes of deep-focus

earthquakes

Scientist 1

Surface earthquakes occur when rock in the Earth’s

crust fractures to relieve stress However, below 50 km,

rock is under too much pressure to fracture normally

Deep-focus earthquakes are caused by the pressure of fluids

trapped in the Earth’s tectonic plates As a plate is forced

down into the mantle by convection, increases in

temperature and pressure cause changes in the crystalline

structure of minerals such as serpentine In adopting a

denser configuration, the crystals dehydrate, releasing water

Other sources of fluid include water trapped in pockets of

deep sea trenches and carried down with the plates

Laboratory work has shown that fluids trapped in rock pores

can cause rock to fail at lower shear stresses In fact, at the

Rocky Mountain Arsenal, the injection of fluid wastes into

the Earth accidentally induced a series of shallow-focus

earthquakes

Scientist 2

Deep-focus earthquakes cannot result from normal

fractures, because rock becomes ductile at the temperatures

and pressures that exist at depths greater than 50 km

Furthermore, mantle rock below 300 km is probably totally

dehydrated because of the extreme pressure Therefore,

trapped fluids could not cause quakes below that depth A

better explanation is that deep-focus quakes result from the

slippage that occurs when rock in a descending tectonic

plate undergoes a phase change in its crystalline structure

along a thin plane parallel to a stress Just such a phase

change and resultant slippage can be produced in the

laboratory by compressing a slab of calcium magnesium

silicate The pattern of deep-quake activity supports this

theory In most seismic zones, the recorded incidence of

deep-focus earthquakes corresponds to the depths at which

phase changes are predicted to occur in mantle rock For

example, little or no phase change is thought to occur at

400 km, and indeed, earthquake activity at this level is

negligible Between 400 and 680 km, activity once again increases Although seismologists initially believed that earthquakes could be generated at depths as low as 1,080 or 1,200 km, no foci have been confirmed below 700 km No phase changes are predicted for mantle rock below 680 km

7. Scientists 1 and 2 agree on which point?

A Deep-earthquake activity does not occur below 400

km

B Fluid allows tectonic plates to slip past one

another

C Water can penetrate mantle rock.

D Rock below 50 km will not fracture normally.

8. The graph below shows the pressures that exist at various depths below the Earth’s surface According

to Scientist 2, which point might represent the focus

of a deep earthquake?

0 0 0 1 0 2 0 3 0 4

pressure (10 dynes/cm )12 2

transition zone to lower mantle

upper mantle

crust

M

N

O

P

1000

200

900 800 700 600 500 400 300

100 0

F. M

G N

H O

J. P

4 ● ● ● ● ● ● 4

9. Which of the following is evidence that would

support Scientist 1’s hypothesis?

A The discovery that water can be extracted from

mantle-like rock at temperatures and pressures

similar to those found below 300 km

B Seismographic indications that earthquakes occur

300 km below the surface of the Earth

C The discovery that phase changes occur in the

mantle rock at depths of 1,080 km

D An earthquake underneath Los Angeles that was

shown to have been caused by water trapped in

sewer lines

10. Both scientists assume that:

F. deep-focus earthquakes are more common than

surface earthquakes

G trapped fluids cause surface earthquakes.

H the Earth’s crust is composed of mobile tectonic

plates

J. deep-focus earthquakes cannot be felt on the

Earth’s crust without special recording devices

11. To best refute Scientist 2’s hypothesis, Scientist 1

might:

A find evidence of other sources of underground

water

B record a deep-focus earthquake below 680 km.

C find a substance that doesn’t undergo phase

changes even at depths equivalent to 680 km

D show that rock becomes ductile at depths of less

than 50 km

12. According to Scientist 1, the earthquake at Rocky

Mountain Arsenal occurred because:

F. serpentine or other minerals dehydrated and released

water

G fluid wastes injected into the Earth compressed a

thin slab of calcium magnesium silicate

H fluid wastes injected into the Earth flooded the

remains of a deep-sea trench

J. fluid wastes injected into the Earth lowered the

13. Scientist 2’s hypothesis would be strengthened by evidence showing that:

A water evaporates at high temperatures and

pressures

B deep-focus earthquakes can occur at 680 km.

C stress has the same effect on mantle rock that it

has on calcium magnesium silicate

D water pockets exist at depths below 300 km.

4 ● ● ● ● ● ● 4

Passage III

The resistance (R) of a conductor is the extent to which

it opposes the flow of electricity Resistance depends not

only on the conductor’s resistivity (r), but also on the

conductor’s length (L) and cross-sectional area (A) The

resistivity of a conductor is a physical property of the

material which varies with temperature

A research team designing a new appliance had to

decide what type of wire to use in a particular circuit The

most important consideration was the wire’s resistance

The team studied the resistance of wires made from four

metals — gold (Au), aluminum (Al), tungsten (W), and

iron (Fe) Two lengths and two gauges (diameters) of each

type of wire were tested at 20° C The results are recorded

in the table below

10-gauge wire

A=5.26mm2

16-gauge wire A=1.31mm2

Note : Area of a circle = πr2

Material Resistivity Length Cross- Resistance

(mW ◊ cm) (cm) sectional (mW)

area (mm2)

Fe 10.00 2.0 1.31 1,528.0

14. Of the wires tested, resistance increases for any given material as which parameter is decreased?

F. Length

G Cross-sectional area

H Resistivity

J. Gauge

15. Given the data in the table, which of the following best expresses resistance in terms of resistivity, cross-sectional area, and length?

A.

A

L

B.

L

A

C. AL

D. AL

16. Which of the following wires would have the highest resistance?

F. A 1-cm aluminum wire with a cross-sectional area

of 3.31 mm2

G A 2-cm aluminum wire with a cross-sectional area

of 3.31 mm2

H A 1-cm tungsten wire with a cross-sectional area

of 0.33 mm2

J. A 2-cm tungsten wire with a cross-sectional area

of 0.33 mm2

17. According to the information given, which of the following statements is (are) correct?

I 10-gauge wire has a larger diameter than 16-gauge wire

II Gold has a higher resistivity than tungsten III Aluminum conducts electricity better than iron

A I only

B II only

C III only

D I and III only

4 ● ● ● ● ● ● 4

4 ● ● ● ● ● ● 4

STOP! END OF SECTION 4

DO NOT TURN TO ANY OTHER SECTION.

18. Which of the following graphs best represents the

relationship between the resistivity ( ) of a tungsten

wire and its length?

F.

L

G.

L

H.

L

J.

L