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Scientific Method DQ 2014-2015
1. Which statement(s) is a quantitative observation?
A. The roses bloomed in the colors of red, yellow, and orange.
B. Salmon swim upstream to spawn.
C. The average size of a blue crab is 9 inches long and 1 to 2 lbs in weight.
D. The class of students had to shake the plastic bag for eight minutes to make their ice cream.
Justification---______
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The graph shows the results of an experiment that tested the effect of time on the growth of a plant. A student measured the height of several plants for ten weeks and determined the average height.
2. Identify one variable that should be held constant during this experiment.
3. According to the graph above, what will the average height of the plants be at week 11 if growth continues at the same rate as in weeks 8 through 10?
4. Jared investigated chemical reactions based on smell, color change, and release of bubbles. What type of evidence would support any conclusion Jared makes?
A. An observationB. An estimationC. A calculationD. A measurement
Justification---______
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5. A valid study would include a control group containing —
Abean seed, tomato seed, sunflower seed, and water
Bwater and 2% root hormone
Cwater only
Dbean seed, tomato seed, sunflower seed, water, and 1% root hormone
Justification---______
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6. Students in a biology class thought that salt water would affect the movements of planaria. They put 25 planaria in salt water and recorded their observations. Which flaw was present in the design of their experiment?
A. There was no hypothesis.
B. There was no control.
C. The sample was too big.
D. The procedure was too complicated.
Justification---______
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7. A student constructs several terrariums like the one shown. Each terrarium is exposed to a different amount of sunlight each day. In order to determine the ideal amount of sunlight, which of the following variables must be held constant?
A.Type of plantsB. Growth rate of plants
C.Wavelengths of sunlightD. Amount of sunlight received
Justification---______
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8. Two students are studying the effect of insects on plant growth. They prevent insects from eating some plants by covering the plants with a transparent mesh cloth. The students leave the other plants uncovered. Both students use the same pots and the same type of soil for each plant. The table shows details of their investigations. Which statement describes a weakness in the investigations?
A. Student X used an equal number of plants.
B. Student X exposed the plants to varying sunlight.
C. Student Y covered half the plants with mesh cloth.
D. Student Y potted the plants in the same type of soil.
Justification---______
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9. Tetanus is a disease caused by a certain type of bacteria. It can be prevented by a vaccine.The following graph shows changing rates of tetanus in the United States.
Which of these is a logical summary for the data in the graph?
A. Quantitative data indicating that people will develop immunity to the bacteria
B. Qualitative data indicating that the bacteria that caused tetanus are now extinct
C. Qualitative data indicating that tetanus has become more deadly over the past 100 years
D. Quantitative data indicating that routine vaccination resulted in a decline in the numberof cases
Justification---______
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10. Planaria are flatworms that are found in shallow streams, often attached to the bottoms of rocks. A class is studying a population of planaria in a nearby shallow stream.
The graph below shows data collected over 11 weeks.
The population started to decrease after 5 weeks. The students concluded that the stream did not have enough food to support a large population of planaria. If this trend continues, how many planaria will be living in the stream by the 12th week?
A. 600B. 500C. 400D. 300
Justification---______
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Scientists wanted to know whether certain bacteria could break down oils they consume.A team of scientists investigated the amount of oil that three different kinds of bacteriacould break down. They placed a colony of each type of bacteria in a separate container.The containers were kept under the same conditions and given the same amount of oil.The scientists measured how much oil remained in each colony of bacteria after certainperiods. The following table shows their results.The scientists concluded that Bacteria B must make an enzyme that allows them to breakapart oil particles.
11. One of the scientists wants to run theexperiment a second time but providedifferent amounts of oil for each colonyof bacteria.How would this affect the validity of anyconclusion for this experimental design?
A. It would be valid because threedifferent bacteria were tested.
B. It would be valid because theexperiment was conducted two times.
C. It would not be valid because theamount of bacteria will still consumethe oil.
D. It would not be valid because theamount of oil provided is not beingcontrolled.
Justification---______
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12. A university biologist is skeptical of the scientists’ conclusion. She suggests that the oil used could have broken
down naturally and may not have been consumed by the bacteria. How should the team of scientists address this concern?
A. Run the experiment again, but change the amount of time for each trial.
B. Run the experiment several times, but use oil that does not break down naturally.
C. Run the experiment several times until the results match the biologist’s concern.
D. Run the experiment again in the same manner as the first trial to confirm the original data.
Justification---______
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13. As part of an experiment to measure decomposition rates of different materials, students put food scraps from the cafeteria in compost bin A and leaves and grass clippings in compost bin B for six weeks. Students in first period measured the temperature in bin A, and students in sixth period measured the temperature in bin B.
What is the greatest error in the students’ experimental design?
A. There are too many uncontrolled variables in the experiment.
B. Temperature is the only dependent variable in the experiment.
C. The materials chosen decompose too rapidly.
D. The students put equal masses of materials in each bin.
Justification---______
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14. A class performed an experiment with four brands of paper towels. - One sheet of each brand was soaked in
200 mL of water for 1 minute. - A 5-g cube was placed on each paper towel and more 5-g cubes were added until the towel began to tear. The table shows the students’ observations. Strength of Paper Towels
Brand / Time Soaked / Mass HeldA / 60 sec. / 45 g
B / 60 sec. / 75 g
C / 60 sec. / 50 g
D / 60 sec. / 80 g
What is the independent (manipulated) variable in this experiment?
A. The brand of paper towel
B. The amount of water used
C. The mass each towel held
D. The amount of time soaked
Justification---______
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15. Ten frogs were placed in a large container with three sections. Each section had equal amounts of light, shelter, food, and water. Each section was painted a different color: red, green, or blue. Daily observations were made of the frogs’ locations for six weeks. These data were compiled to produce the following frog location frequencies. Red area = 31% Green area = 35% Blue area = 34%
Which conclusion about the frogs is supported by these data?
A Four frogs out of ten preferred the green area.
B The frogs randomly moved into the colored areas.
C Most frogs tended to avoid the red area.
D Most frogs preferred the color blue.
Justification---______
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16. Meg investigated the ability of different plants to decrease soil erosion. She performed thefollowing steps:
1) Planted five different species of plants, each in its own box
2) Set up the boxes in the same manner with one end of each box propped up at thesame angle
3) Placed a collection device at the bottom of each box to catch soil runoff
4) Released water over each box in the same manner
5) Measured the amount of soil runoff and recorded the appearance of the water
The table shows Meg’s data.
Based on both quantitative and qualitative data, which is a logical inference for thisinvestigation?
A. The less able the plant was to prevent soil erosion, the clearer the water and the less soilthat eroded.
B. The cloudier the water, the more soil that eroded and the less able the plant was to preventsoil erosion.
C. The clearer the water, the more soil that eroded and the better able the plant was toprevent soil erosion.
D. The better able the plant was to prevent soil erosion, the cloudier the water and the moresoil that eroded.
Justification---______
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17. Before 1896, many scientists concluded that light could not pass through black paper. In 1896, Henri Becquerel observed that uranium salts could cause a plate covered by black paper to react as if light had reached it. How did this observation affect conclusions about light passing through black paper?
A. Scientists ignored Becquerel’s evidence because uranium is dangerous to use, so his study was not valid.
B. Scientists repeated Becquerel’s experiment until it no longer worked and reported that his conclusions were not valid.
C. Scientists had to revise their earlier conclusion because evidence from Becquerel did not support the original conclusion.
D. Scientists stood behind the earlier conclusion that black paper blocks light because it was already an accepted conclusion.
Justification---______
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18. The graphs show the results of two separate experiments on the same species of plant. Students now want to determine how the use of rainwater or bottled water affects the growth of this plant. Which conditions should be used for optimal growth as the two water types are tested?
A. 20°C, 10 mL/dayB. 25°C, 35 mL/day
C. 30°C, 45 mL/dayD. 35°C, 20 mL/day
Justification---______
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