What is the central idea of the entire passage about density?

• Density is a formula that students must memorize.

• Density is a unifying scientific concept used across many disciplines.

• Density is only important for classifying minerals.

• Density is rarely applied outside chemistry.

Which sentence best states the central idea of the passage?

• “Density is one of the simplest yet most powerful ideas in science.”

• “Saturn’s density is so low it could float in water.”

• “Oil floats on seawater because it is less dense.”

• “Geologists use density to identify minerals.”

How does the author develop the central idea that density connects sciences?

• By showing how density explains phenomena in chemistry, astronomy, geology, and environmental science.

• By listing only chemical examples of density.

• By focusing on the history of density measurements.

• By showing density is useful only in laboratory settings.

What is the central idea of the conclusion?

• Density is only relevant for chemistry students.

• Density demonstrates how science disciplines are separate.

• Density is a simple ratio with wide-ranging implications.

• Density is not useful in environmental science.

Which detail best supports the central idea that density explains natural processes across scales?

• Icebergs float because ice is less dense than liquid water.

• Seismic waves travel at different speeds.

• Gold is denser than pyrite.

• All of the above.

What is the central idea of the chemistry section?

• Density reflects how tightly particles are packed and helps identify substances.

• Density is only important for measuring gases.

• Density explains why helium balloons pop.

• Density cannot be used in mixtures.

Which example best supports the central idea of the chemistry section?

• A) Oil floats on water because it is less dense.

• B) Stars collapse into white dwarfs.

• C) Earth’s crust is less dense than the mantle.

• D) Climate change affects ocean currents.

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NGSS.MS-PS1-2

Which of the following sentences best summarizes the central idea of the chemistry discussion?

• A) “A cube of aluminum and a cube of lead may be the same size, but the lead feels heavier.”

• B) “Density is often used as an identifying property.”

• C) “Chemists manipulate mixtures to study density.”

• D) “Understanding density differences lets chemists predict outcomes.”

Why does the author emphasize aluminum and lead cubes?

• To illustrate how density differences can be detected even when volume is the same.

• To explain how metals conduct electricity.

• To describe how mixtures separate.

• To show why gases are denser than solids.

The central idea of the paragraph describing helium balloons is:

• Helium is more colorful than other gases.

• Density differences explain why some gases rise and others sink.

• Balloons are fragile and pop easily.

• Helium balloons are lighter than paper.