NGSS.MS-PS2-5

Water striders can walk across the surface of calm water. Their feet push the surface of the water down slightly, but they do not break the surface. Why?

• The insects are light enough so they do not break the hydrogen bonds holding the water molecules together
  
• The insects actually use their wings to hover slightly above the water’s surface and they only skim it with their feet.
• The insect’s feet are non-polar, so they are repelled by the polar water molecules and are pushed away from the water’s surface.
• The insects are small enough to see the individual water molecules, so they are able to step carefully from one molecule to the next
  

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NGSS.MS-PS2-5

Testing a hypothesis often involves a(n):

• answer
• experiment
• problem
• safety check

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NGSS.MS-PS2-5

Magnets can interact without touching.

• True
• False

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NGSS.MS-PS2-5

When two magnets are pushed away from one another they ______.

• Attract
• Pole
• Repel
• Compass

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NGSS.MS-PS2-5

The push or pull between charged objects is an

• electric force
• electric discharge
• electric field

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NGSS.MS-PS2-5

Stephan claims that Earth has both a gravitational field and a magnetic field. Which statement best supports his claim?

• Any object will fall to the ground.

• A bar magnet will fall to the ground.

• Any object will fall to the ground, and a compass can be used for navigation.

• A compass points in the direction of both the magnetic and gravitational fields.

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NGSS.MS-PS2-5

S8P5a Which of the following statements about gravitational fields is true?

• Gravitational fields affect objects only when two objects are touching

• Gravitational fields affect objects only if the objects are not in contact

• Any object that has a mass is surrounded by a gravitational field

• Only very massive objects, such as Earth, are surrounded by a gravitational field

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NGSS.MS-PS2-5

Any object with mass is surrounded by a gravitational field.

• True

• False

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NGSS.MS-PS2-5

Which is an example of a non-contact force?

• elastic force

• normal force

• applied force

• electric force

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NGSS.MS-PS2-5

current flowing through a wire is surrounded by a/an

• force field

• magnetic force

• nothing

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NGSS.MS-PS2-5