Are You Smarter Than An 8th Grader

NASA’s NEAR mission aimed to land a spacecraft on the asteroid Eros. Engineers simulated different landing-rocket burn times to reduce speed. The spacecraft can land safely at a speed between 1.51.5 - 1.81.8 m/s. What would happen to the NEAR spacecraft if engineers used the burn time from Simulation 3 for the mission to Eros? Mark only one oval.

• The spacecraft would hit Eros with a larger force than the force received back from Eros on landing. This could cause the asteroid to move.

• The spacecraft would hit Eros with a smaller force than the force received back from Eros on landing. This could cause the spacecraft to bounce high off the surface of the asteroid.

• The spacecraft would hit Eros with a large force, receiving an equally large force from Eros on landing. This could damage the spacecraft.

• The spacecraft would hit Eros with a small force, receiving a large force from Eros on landing. This could allow the spacecraft to land safely.

Answer explanation

Using the burn time from Simulation 3 would result in a large impact force on Eros, which would generate an equal reaction force back on the spacecraft. This could potentially damage the spacecraft upon landing.

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NGSS.MS-PS3-5

NGSS.MS-PS2-4

NGSS.MS-PS2-5

Which type of signal would be most reliable for sending information over long distances? Mark only one.

• an analog signal sent over low-frequency radio waves

• a digital signal sent over low-frequency radio waves

• a digital signal sent over high-frequency radio waves

• an analog signal sent over high-frequency radio waves

Answer explanation

A digital signal sent over low-frequency radio waves is more reliable for long distances due to better noise resistance and error correction capabilities compared to analog signals, making it the best choice.

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NGSS.MS-PS4-3

The diagram shows the change in the emission spectrum of a distant galaxy over time when observed from Earth. Which conclusion about the galaxy is correct? Mark only one oval.

• The galaxy is growing.

• The galaxy is shrinking.

• The galaxy is moving toward Earth.

• The galaxy is moving away from Earth.

Answer explanation

The emission spectrum shows a shift towards shorter wavelengths, indicating a blue shift. This suggests that the galaxy is moving toward Earth, as objects moving closer exhibit this phenomenon.

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NGSS.HS-ESS1-2

The diagram shows the convection currents that occur within Earth’s mantle. Which explains the movement of the mantle material by convection currents? Mark only one.

• The mantle material cools due to contact with the air above the tectonic plates, where it solidifies and becomes more dense and stable.

• The mantle material cooled by the air near the crust becomes less dense, causing it to move and bring up more dense material by the core.

• The mantle material heats as it moves under the tectonic plates, causing it to expand and spread, pushing it away from the crust.

• The mantle material heated by the outer core becomes less dense and rises, pushing away cooler mantle material under the tectonic plates.

Answer explanation

The correct choice explains that mantle material heated by the outer core becomes less dense and rises, which drives convection currents. This process pushes cooler, denser material down under the tectonic plates.

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NGSS.MS-ESS2-1

A teacher puts a glass cup, half-filled with water, on top of a speaker and plays music. Wave-like patterns form in the water. When the volume of the music is increased, the size of the waves on the water increases. When the pitch of the music is increased, the waves appear to be more closely spaced than before. How do the tests compare to each other? Mark only one.

• In both tests, the sound waves had more energy after the teacher changed the music.

• Increasing the volume of the sound wave results in more energy, but increasing the pitch of the sound wave results in less energy.

• In both tests, the sound waves had less energy and were able to affect the water less.

• Increasing the volume of the sound wave results in less energy, but increasing the pitch of the sound wave results in more energy.

Answer explanation

Increasing the volume of the sound wave adds more energy, causing larger waves. In contrast, increasing the pitch results in waves that are more closely spaced but does not increase energy, making the correct choice accurate.

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NGSS.MS-PS3-5

NGSS.MS-PS4-1

NGSS.MS-PS4-2