When is an investigation also an experiment?

• when it involves measurement

• when it represents key characteristics of a system

• when it observes living organisms in their natural habitat without altering the setting

• when it involves the identification and control of variables

The 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?

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

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

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

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

A controlled experiment is a means of carrying out a fair test of a hypothesis. In a controlled experiment, all of the variables that can influence the outcome variable (dependent variable) of the experiment are controlled or held constant, except for the test variable (independent variable). Which of the following hypotheses would not be tested using a controlled experiment?

• A geologist’s hypothesis about how the Grand Canyon formed.

• A biologist’s hypothesis that the use of fertilizer increases the growth of grass.

• A geologist’s hypothesis that acid rain weathers sedimentary rock more rapidly than igneous rock.

• A biologist’s hypothesis that increases in average temperatures cause an increase in honey bee population.

Henry wants to make a model to learn about a science topic. Which topic can Henry learn about best by using a model?

• what marsh plants thrive in nearby wetlands

• how the sun’s rays cause lunar eclipses

• what call a cardinal makes early in the morning

• all of insects that live in the rainforests of Brazil

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NGSS.MS-ESS1-1

Computer simulations can sometimes be beneficial. Which of these investigations would not benefit from a computer simulation?

• training airline pilots

• predicting the path of a hurricane

• designing an earthquake-proof building

• understanding how soft rocks feel

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NGSS.MS-ETS1-4

Mandy is investigating migration. She thinks that birds instinctively fly south for the winter and hypothesizes that they do so because they cannot survive in cold weather. Which of the following could serve as empirical evidence to support her hypothesis?

• charts displaying birds’ migratory patterns in relation to weather

• feelings based on her own reactions to winter weather

• data from another scientist’s experiment on bird anatomy

• inferences made about the birds based on observations of flocks of flying geese

Unprotected exposure to the sun’s rays is a factor in the development of skin cancer. Which of the following is an example of empirical evidence that supports this hypothesis?

• an advertisement for a sun block product that claims it protects skin for ultraviolet rays

• data demonstrating a relationship between amount of sun exposure and incidences of skin cancer

• a skin cancer survivor’s recollection that he had a bad sunburn as a child

• a model of a skin cell showing where DNA is in the cell

A model can represent an object, system, or process. Why do all models have limitations?

• because all models are two-dimensional

• because a model includes every factor that affects it

• because a model is smaller than the thing it represents

• because a model is never exactly the same as the thing it represents

Tags

NGSS.MS-ETS1-4

Roberto does a study comparing how plant growth is affected by sunlight. He shares the following chart with his classmate Ava. Ava is trying to follow the accepted practices of the scientific community, so she asks Roberto to document his research methods. Which best explains why this is an important step?

• because it is not clear from the chart alone whether Roberto used the same type of plant

• because scientists are often dishonest about their results and it’s important to make sure that Roberto is telling the truth

• because Ava and Roberto’s peers will want to repeat his experiment and confirm his results before they accept his explanation

• because Ava is curious and may have a better way of doing the experiment

A scientist wants to know why the honeybee population is declining. Which step would the scientist most likely to do first?

• Research to see if there is already a widely accepted explanation.

• Observe the problem and make a hypothesis about what is causing it.

• Communicate the question to as many other scientists as possible so that they can discuss it.

• Conduct an experiment to see if increased pollution is causing a decrease in the honeybee population.