AccelePrep for the ACT Test 2nd Edition Student Text

C HAPTER 10 | F AST T RACK TO S CIENCE M ECHANICS • 183

ANSWERS

1. (C) Science/Evaluation of Models/Analysis Scientist 1 assumes that the radioactive material was formed at the same time as the earth; otherwise, there is no connection between the radioactive “clock” and the age of the earth. 2. (F) Science/Evaluation of Models/Analysis For the landing of the meteorites to upset the “clock,” they would have to contain the radioactive material or its disintegration products. Since Scientist 2 claims that the estimate of the earth’s age is too low, the meteorites must contain radioactive material and have landed since the formation of the earth, thus upsetting the “clock.” 3. (D) Science/Evaluation of Models/Analysis Since Scientist 2’s theory is based on the assumption that the earth is the constant recipient of meteorites that contain radioactive ƒ–‡”‹ƒŽǡ ϐ‹†‹‰ ˆ‡™ ‡–‡‘”‹–‡•…‘–ƒ‹‹‰ radioactive material undermines the theory.

4. (G) Science/Evaluation of Models/Analysis According to Scientist 2, the amount of radioactive material and its disintegration products would increase over time because meteorites would bring more material, while the earth has no way of getting rid of it. 5. (C) Science/Evaluation of Models/Analysis Since there is no additional source for new radioactive material, the amount of radioactive material as it decays through the various disintegration products is constant.