7th GradePerformance Matters

2014/2015

Question 1Students are studying the effects of pollution by counting populations of insects in two different locations. One location is near a parking lot, and the other location is a meadow. The students plan to count and identify all insects located within 1 square meter at each location. They will repeat the insect count for 10 days and thenanalyze the data.

What is the dependent variable in this study?• A. the size of the area examined• B. the location where insects were counted• C. the number of insects counted at each location• D. the number of days the insects were counted

Question 2

Why is it necessary to control all but one variable when an experiment is conducted?

• A. to identify how the variable alone is affecting the results• B. to control the independent variable during an experiment• C. to make graphing data more simple during an experiment• D. to limit the number of times the experiment must be

repeated

Question 3 The image shows a food web in a small ecosystem. A new species moves into the ecosystem. The new species consumes only snakes. Scientists are interested in predicting how the new species will impact the food web.

Which of the following is most likely to be a correct prediction based on the information in the food web?

• A. The toad population will increase.• B. The insectivorous bird population will

decline.• C. The new species is a prey for the owls

and hawks.• D. The new species will form a

competitive relationship with the snakes.

Question 4

Lucas theorizes that changing the slope of a ramp will affect how far a toy car travels down the ramp. To test this theory, Lucas builds two ramps with different slopes. Lucas sends a toy car down each ramp one time. After measuring with a meter stick the distance each toy car traveled, Lucas concludes that the steeper slope caused the toy car to travel farther. What would happen if Lucas conducted three trials on each ramp?• A. Lucas would replicate the study.• B. Lucas would improve the validity of the results.• C. Lucas would prove the hypothesis was correct.• D. Lucas would increase the accuracy of his measurements.

Question 5A group of students is investigating what kind of bird feeders bluebirdsprefer. The students have several similar bird feeders set up in an open field with the same type and amount of bird seed in each. The feeders have the following shapes and colors:

3 red round feeders 3 red square feeders 3 blue round feeders 3 blue square feeders

What kind of scientific investigation are the students using?• A. simulation• B. data interpretation• C. scientific experiment• D. theoretical prediction

Question 6

Samantha wants to investigate the effect of different colored lights on the growth of bean plants.

What would be considered the dependent variable in this investigation?

• A. the plants that receive only white light• B. the type of soil the plants are grown in• C. the amount the bean plants grow over time• D. the different colors of light the plants receive

Question 7

Which of these components must a scientific investigation contain in order to meet the criteria of an experiment?

• A. two or more changed variables• B. use of time as a measured variable• C. control of all variables except for one• D. results reported in the form of a graph

Question 8 Two students design a science fair project. They plan to test the effect of different colors on the amount of heat generated from the absorption of light. They will fill six identical jars with water and put a lid on top of each jar. Each lid will have space for a thermometer to be placed in the water of the jar. Each of five jars will be wrapped with a different color of paper, and the sixth jar will be left unwrapped. All six jars will be placed near a light source for one hour. The temperature change of the water in each jar will be recorded after one hour. This is the students' materials list is on the left.

Which of these materials would be used for the test or independent variable?

A. timerB. light sourceC. thermometerD. black, red, yellow, blue, and white paper

This is the students' materials list:

. six identical glass jars with lids

. black, red, yellow, blue, and white paper. scissors. tape. water. timer. thermometer. light source. helper with a drill to punch a hole in each lid

Question 9The water level in McColm Pond went down drastically during a drought last summer. Some students decide to monitor the water level during a school year. There is a dock over the pond.

Which is the best method for collecting data on the level of water in the pond?

• A. Visit the pond each month and measure the water depth with a measuring pole at the end of the dock.

• B. Visit the pond at the end of the year and measure the water depth with a measuring pole at different spots.

• C. Visit the pond each month and measure the water depth with a measuring pole at a different spot each month.

• D. Visit the pond at the end of the year and measure the water depth with a measuring pole at the end of the dock.

Question 10How Ants Herd Aphids Aphids are small insects that suck sap from plants for nutrition. This diet provides the aphids with more sugar than needed. The aphids secrete the extra sugar as a sweet liquid called honeydew.It is more energy efficient for ants to consume honeydew than plants. Because of this, an interesting relationship between the ants and aphids has developed. Ant colonies will adopt and tend aphid colonies. The ants provide such services as protecting their aphids from predators (ladybugs, for instance), looking after aphid eggs through winters, and moving aphids to new plants. In return, ants receive a steady supply of honeydew.Scientists have questioned the exact mechanics of this complex relationship between ants and the aphids. How do ants keep aphids under control? An answer to part of this problem was discovered by a team of English scientists in2007. The scientists already knew that ants leave chemical “footprints” in places while walking. The English scientists placed sheets of identical paper for the aphids to walk on. Ants had walked on some sheets and not on others. Aphids walked over both types of paper, and their walking speed was recorded. The aphids’ walking speed was extremely slow on the paper the ants had previously walked on, compared with the clean paper. The scientists then repeated the experiment using dead leaves instead of paper. Aphids tend to move away from dead leaves as rapidly as possible, since they cannot obtain nutrition from them. Once again, the scientists observed much slower movement when the aphids were placed on dead leaves covered in the chemical footprints of ants.These experiments demonstrated that ants herd aphids by exposing the aphids to chemicals which slow them down.

Which piece of evidence from the passage best supports the conclusion that ants manage aphids through chemical controls?

• A. Ants walked on some sheets of paper but the aphids walked on all the sheets of paper.

• B. Aphid movement was slowed when they walked where the ants had walked.

• C. Aphids produce honeydew, which ants prefer to eat.

• D. Ants look after aphid eggs throughout the winter.

Question 11A student observes a toy car as it rolls down a ramp. He calculates the speed of the car at one ramp height to be 1 meter per second (m/s), and at a lower ramp height to be 0.5 m/s. He concludes that the speed of the car increases as he increases the height of the ramp. Which statement explains whether the student's results were either theoretical or empirical?

• A. theoretical, because he did not use controls• B. empirical, because he directly observed the changes in the speed of

the car• C. empirical, because he repeated the experiment multiple times at each

ramp height• D. theoretical, because he had to determine the speed of the car by

dividing distance by time

Question 12

What must occur before new scientific knowledge is accepted by thescientific community?

• A. The results must be debated, analyzed, and repeated by other scientists.

• B. The work must be unrepeatable by other scientists to demonstrate its originality.

• C. The data must be presented to a single scientist who will determine if it is accepted or not.

• D. The experiment must be completely unique and not build on the work of other scientists or current scientific knowledge.

Question 13

Geologists have found that the continents of Earth appear to have once fit together like a jigsaw puzzle. They have also found similar fossils along the edges of these continents. These two facts have provided for the eventual acceptance of which ofthe following theories?

• A. evolution• B. plate tectonics• C. the origin of life• D. extinction of the dinosaurs

Question 14The graph to the right shows how carbon dioxide (CO2) levels have changedover time. For many years, scientists argued that variations in carbon dioxide levels being observed were natural, and that climate change was not a problem. At some point, however, many of these same scientists began to draw a different conclusion.

Which of the following observations would have caused many scientists to conclude that climate change is occurring?

A. Current levels of CO2 are higher than any observed over the last 400,000 years.B. Current CO2 level measurements are more accurate than they were 50 years ago.C. Today scientists have more sophisticated computer programs for graphing CO2 levels.D. Today scientists have a better understanding of how CO2 is distributed in the

Question 15

Which statement is a part of a scientific theory?

A. Energy cannot be created or destroyed.B. The universe began expanding fourteen billion years ago.C. An object in motion stays in motion unless an external force acts on the object.D. The gravitational force between two objects depends on the mass of each object and the distance between the objects.

Question 16

Which of these statements describes a limitation of scientific laws?

A. Laws do not have worldwide acceptance.B. Laws do not explain why something is happening.C. Laws do not provide opportunities to be disproven.D. Laws do not describe natural phenomena with enough detail.

Question 17 These two diagrams show the history of cell-membrane models.

Which statement best describes the change in the cell-membrane model?

A. The new model was the result of a vote by scientists.B. The new model helped scientists avoid more research.C. The new model was based on the researchers’ best guess.D. The new model came from more experiments and evidence.

Question 18

Scientific models help scientists visualize phenomena that cannot be directly observed. Which model limitation most likely applies to a classroom model of the solar system?

• A. It is not to scale.• B. It is two-dimensional.• C. The planets do not orbit.• D. The planets are not labeled.

Question 19

Energy from the Sun travels through space to Earth. What property of the Sun's radiation do scientists use to classify the radiation into different categories?

• A. They classify it by the wavelength of the radiation.• B. They classify it by the speed of each type of radiation.• C. They classify it by the path the radiation takes through

space.• D. They classify it by the effect the radiation has on the

organisms of Earth.

Question 20

Which of the following parts of the electromagnetic spectrum has the shortest wavelength?

• A. ultraviolet radiation• B. infrared radiation• C. radio waves• D. microwaves

Question 21

Laila places a straw in a glass of water. She notices the straw's appearance looks different in the water, as shown below.

What causes the straw to appear broken?• A. Light is being reflected.• B. Light is being absorbed.• C. Light is being refracted.• D. Light is becoming transparent.

Question 22

Which of these statements is a correct explanation of how objects absorb and reflect colors of light?

• A. Black objects absorb almost all wavelengths of light.• B. White objects both absorb and reflect almost all

wavelengths of light.• C. Red objects absorb red light and reflect all other

wavelengths of light.• D. Blue objects absorb none of the wavelengths of light and

reflect only blue light.

Question 23

Waves produce a disturbance in the material they travel through. As a result, waves travel at different speeds through different materials.

Through which of these would sound waves travel at the greatest speed?• A. a gas• B. a solid• C. a liquid• D. a vacuum

Question 24

Light from the Sun takes about 8 minutes to reach Earth.Why does light from the Sun travel so quickly to Earth?

• A. Light waves travel fastest through solids.• B. Light waves travel fastest through gases.• C. Light waves travel fastest through liquids.• D. Light waves travel fastest through a vacuum.

Question 25

What will be the effect on a cube of ice in a closed container left on a counter at room temperature for 30 minutes?

• A. The cube will continue to have the same shape and volume.• B. The cube will melt and take on the shape and volume of the

container.• C. The cube will melt and take on the shape of the container, but not

the volume.• D. The cube will melt and take on the volume of the container, but

not the shape.

Question 26

Which group of physical properties identifies a solid?

• A. no definite shape, no definite volume, and slow-moving atoms

• B. definite shape, definite volume, and slow-moving atoms• C. definite shape, no definite volume, and fast-moving

atoms• D. no definite shape, definite volume, and fast-moving

atoms

Question 27

Which of the following actions involves an energy transformation of changing light energy into electrical energy?

• A. using a gasoline-powered car• B. using a solar-powered calculator• C. using charcoal on an outdoor grill• D. using a battery-powered cell phone

Question 28

Which energy conversion occurs in a gasoline-powered automobile engine?

• A. potential to light• B. electrical to chemical• C. mechanical to chemical• D. chemical to mechanical

Question 29

Patrice slides a textbook across a table. Shortly after the book is released from her hand, it begins to slow down and appears to lose energy. Which statement best explains where the energy goes as the book slows down?

• A. It is transferred to the air in the form of potential energy.• B. It is transferred to the table in the form of thermal energy.• C. It is transferred to the book in the form of potential energy.• D. It is transferred to Patrice's hand in the form of thermal

energy.

Question 30 EFFICIENCY OF LIGHT BULB TYPES IN PRODUCING VISIBLE LIGHTVarious types of light bulbs

transform more electrical energy into heat energy instead of light energy.

Which of these types of light bulbs transforms the most electrical energy into heatenergy?A. compact fluorescentB. incandescentC. halogenD. white LED

Technology Average Percent

EfficiencyCompact fluorescent

65

Incandescent 15

Halogen 22

White LED 35

Question 31

The table to the right lists four objects, each at a different temperature.If two of these objects are placed together in a container so the objects are touching,which of these scenarios correctly describes how heat could flow between the objects?

• A. Heat will flow from Object 1 to Object 3.• B. Heat will flow from Object 1 to Object 4.• C. Heat will flow from Object 2 to Object 4.• D. Heat will flow from Object 2 to Object 3.

Objects Temperature (degrees Celsius)

1 22

2 45

3 35

4 100

Question 32Mario takes a cold can of soda out of a refrigerator. He sets the cold can on a table in the room and leaves it there for a few hours. Which of the following best describes what will occur?

• A. The cold from the soda can will reduce the temperature of the air in the room.

• B. Heat from the air will move into the soda can until both reach the same temperature.

• C. The soda in the can will change state and temperature as it releases cold molecules

• into the air.• D. The soda can will absorb heat until it becomes warmer than the

temperature of the• air in the room.

Question 33

Which of these describes the transfer of heat by the circulation or movement of heated material?

• A. conduction• B. convection• C. radiation• D. sublimation

Question 34

Which most accurately describes how a layer of Earth can move to form new land?

• A. As the crust moves, it forces the mantle down toward the outer core, creating new land.

• B. As the inner core moves, large pieces of land are carried out to sea, which form new land.

• C. As the mantle moves, it spreads, cools, and falls, forming new material that develops new land.

• D. As the outer core moves, it pulls the inner core along with it, forcing it upward to form new land.

Question 35

Which layer consists of Earth's crust and upper mantle divided into tectonic plates?

• A. asthenosphere• B. atmosphere• C. hydrosphere• D. lithosphere

Question 36

Which of the following Earth surface events is most likely a result of convection within the layers of Earth?

• A. a tornado• B. a high tide• C. a geyser erupting• D. a jet stream changing

Question 37

The sand found along the Gulf of Mexico coast of Florida originated in granite formed from slowly cooling magma in the Appalachian Mountains. When this sand is buried and compacted, it will become sandstone. The sandstone may be moved deeper underground where it will be subjected to heat and pressure to become quartzite. What is the rock cycle for this sequence of transformations?

• A. igneous rock → metamorphic rock → sedimentary rock• B. metamorphic rock → igneous rock → sedimentary rock• C. igneous rock → sedimentary rock → metamorphic rock• D. metamorphic rock → sedimentary rock → igneous rock

Question 38

A scientist collected a sample of sedimentary rock from a high elevation in the Himalaya Mountains. Using what he knows about the rock cycle and how major landforms are created on Earth, how would the scientist predict that the sedimentary rock became part of a mountain?

• A. A seabed was lifted up when the mountain formed.• B. Several lava flows from the top of the mountain cooled.• C. Water or wind carried the rock there from another location.• D. Pressure from when the mountain formed created the

rock.

Question 39

Which of the following statements provide an accurate description of the formation of igneous rock in the rock cycle?

• A. Igneous rocks are formed by the melting of metamorphic rocks.

• B. Igneous rocks are formed through weathering and erosion of other rocks.

• C. Igneous rocks are formed by the cooling and crystallization of hot magma.

• D. Igneous rocks are formed by the effects of heat and pressure on sedimentary rocks.