ACT Practice - Conflicting Scientists

Which of the following phrases best describes the major point of difference between the 2 scientists' hypotheses?

• The location of the event

• The speed the object was traveling

• The density of Earth's atmosphere

• The type of object that entered Earth's atmosphere

According to Scientist 2's viewpoint, compared to the altitude at which a stony asteroid would have exploded in Earth's atmosphere, a comet of similar size would most likely have exploded at:

• the same altitude.

• a higher altitude.

• a slightly lower altitude.

• a much lower altitude.

Scientist 1's viewpoint indicates that when the materials that compose most of a comet are sufficiently heated, they change to:

• solids.

• gases.

• liquids.

• a vaccum.

Which of the following statements best describes how Scientist 2 would explain why no large, identifiable fragments of the object have been recovered?

• Any large, identifiable fragments that reached the ground have been removed from the area by erosion.

• Any large, identifiable fragments were thrown hundreds of kilometers from the site.

• No large, identifiable fragments of the object reached the ground.

• No large, identifiable fragments of the object have been recovered due to the soil conditions in the area.

How would the behavior of the asteroid differ from that described in Scientist 2's viewpoint if the asteroid had not been flattened by the air pressure difference? The asteroid would:

• not have entered Earth's atmosphere.

• have struck another planet in the solar system.

• have decelerated more gradually.

• have frozen.

Which of the following statements would both scientists most likely use to explain the damage to the forest caused by the object's explosion? Energy from the explosion:

• traveled rapidly down to Earth's surface.

• dissipated in the upper atmosphere.

• was released less than 1 km above Earth's surface.

• was released as the object struck Earth's surface.

Scientist 1's viewpoint would be weakened by which of the following observations about comets, if true?

• Comets are composed mainly of frozen materials.

• Comets are much larger than 100 m in diameter.

• Comets often pass close enough to Earth to intersect Earth's atmosphere.

• Comets orbit the sun.