Grade 8 Nature of Science QUIZZ

Planaria are flatworms that are found in shallow streams, often attached to the bottom 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?

• 600

• 500

• 400

• 300

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NGSS.MS-LS2-1

NGSS.MS-LS2-4

In an eighth-grade science class, there are four lab groups. Group 4 designs an experiment to find out how light affects the germination rate of radish seeds. The students in Group 4 write out their procedure and conduct their experiment. They discover inconsistencies in their data and decide to increase the number of trials to obtain multiple data sets. Which of these most accurately describes how this should be done?

• Group 4 should repeat their procedure multiple times.

• Group 4 should repeat a revised procedure multiple times.

• Group 4 should communicate their procedure to another group for replication. Once we have repeated our testing over and over, and think we understand the results, then it is time for replication.

• Group 4 should communicate a revised procedure to another group for replication.

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NGSS.MS-ETS1-3

Gregor Mendel conducted research about genetics by breeding pea plants. Although he could not actually see into cells, he deduced from his results that each of an organism’s traits is determined by two factors (alleles). Long after Mendel’s work, microscopes were improved, and scientists observed that chromosomes in the nucleus occurred in matching pairs. It is now accepted that the two alleles for each trait are located on homologous chromosomes. What does this demonstrate about science?

• A. Advances in science may result from new interpretations of previous work.

• B. Improvements in equipment and data gathering can disprove previous conclusions.

Kyra is studying the different factors that can affect the growth of a plant. Based on her research, she thinks that the amount of water, the exposure to sunlight and the type of fertilizer may contribute to the growth of the plant. What should Kyra do to test the effect of sunlight and get accurate result in her experiment?

• Change the amount of water and keep the type of fertilizer and the amount of sunlight the same.

• Change the type of fertilizer and the amount of water at the same time and keep the amount of sunlight the same.

• Change the amount of sunlight by placing the plants in different locations and keep the amount of water and the type of fertilizer the same.

• Change the type of fertilizer, the amount of water, and the amount of sunlight at the same time.

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NGSS.MS-LS1-5

NGSS.MS-LS2-1

A scientist spends a month observing two prairie animals, prairie dogs and ferrets, in their natural habitat. Based on his observations, the scientist states that ferrets are more active than prairie dogs. Why is his statement NOT a scientific theory?

• It is an observation of something in nature.

• Prairie dogs and ferrets are different species.

• The statement is not widely accepted and supported by sufficient evidence.

• The scientist has not conducted enough trials to draw a valid conclusion.

Suppose NASA discovers a new planet in a neighboring galaxy. Astronomers want to collect more information about the new planet. Which of the following methods are scientists least likely to use to study the planet?

• Travel to the distant planet and observe it directly.

• (Option not visible in the image)

• (Option not visible in the image)

• (Option not visible in the image)

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NGSS.MS-ESS1-3

Scientists create both scientific theories and scientific laws as they make observations and conduct experiments about the natural world. Which of the following statements most accurately compares the difference between scientific theories and scientific laws?

• A. Scientific laws are based on evidence, while scientific theories are not.

• B. Scientific theories involve only biology, while laws involve all types of science.

• C. Scientific theories involve mathematical equations, while scientific laws are based on observations.

• D. Scientific theories are ideas that explain natural events, while scientific laws more reliably predict natural events.

Some students hypothesize that heating a mixture of any substance and water will always increase the amount of the substance that will dissolve in the water. The table below shows the results of an investigation testing this hypothesis. The results for which of the substances tested weaken this hypothesis?

• Substance W

• Substance X

• Substance Y

• Substance Z

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NGSS.MS-PS1-2

Matthew reads that the density of water is 1 g/cm³. He plans to conduct an experiment to determine if the density of a material plays a role in whether the material floats or sinks in water. He calculates and records the densities of several materials. Next, he places each material in water, observes whether the material sinks or floats, and records his observations. Matthew organizes all the data he collects in the table below.

Which hypothesis is supported by Matthew’s experiment?

• A. Solid objects will sink in water while liquid objects will float.

• B. The ability of an object to float or sink in water is unrelated to density.

• C. Materials less dense than water float in water, while those that are denser than water sink.

• D. Materials less dense than water sink in water, while those that are denser than water float.

Things that stay the same throughout the whole experiment are called

• controls
• dependent variables
• independent variables
• constants