Questions

For multiple choice questions, choose the letter of the best answer choice from the list below the question. For short answer questions, type your answer in the space provided below the question.

Note that there are TWO PAGES OF QUESTIONS below. Each multiple question is worth 3 points and each short answer question is worth 5 points.

Experiment 1

1. In 1 or 2 sentences, describe, in the space below, what you observed happening to the atoms in the decay area when the simulation is in "play" mode.

2. In this simulation (and in nature), carbon-14 is radioactively decays to nitrogen-14. What type of radioactive decay is carbon-14 undergoing?

a. alpha decay b. beta decay c. gamma decay

3. In data table 1, compare your calculations for the average number of atoms that decayed to your predictions for how many atoms would decay. How did your predictions compare to the averages?

a. Close b. Exact c. Nowhere Close

4. Which of the following statements best describes the decay of a sample of radioactive atoms?

a. A statistical process, where the sample as a whole decays predictably, but individual atoms in the sample decay like popcorn kernels popping.
b. An exact process where the time of decay of each atom in the sample can be predicted.
c. A completely random process that is in no way predictable.

5. Based on your observations, the data you collected, and the comparison of the calculated averages to predictions in experiment 1, write in the space below, IN YOUR OWN WORDS, a definition of "half-life". Phrase the definition in a way that you would explain the concept to one of your classmates.

Experiment 2

1. Suppose you found a rock. Using radiometric dating, you determined that the rock contained the same percentage of lead-206 and uranium-238. How old would you conclude the rock to be?

a. 2.25 billion years old b. 4.5 billion years old c. 9 billion years old

2. Using the data in data table 2, if the original sample contained 24 grams of carbon-14, how many grams of carbon-14 would be left, and how many grams of nitrogen-14 would be present, after 2 half-lives?

a. 12; 12 b. 6; 18 c. 2; 22

Experiment 3

1. When half of the carbon-14 atoms in the tree have decayed into nitrogen-14, it has been approximately 5700 years since the tree .

a. was planted b. died

2. The probe measures that the percentage of carbon-14 in the tree is 100% while the tree is alive, and then measures the percentage of carbon-14 decreasing with time after the tree dies. This means that radiometric dating using carbon-14 is applicable to:

a. living objects. B. once-living objects c. both living and once-living objects.

3. When half of the Uranium-238 in the rock has decayed, years have passed since the volcano erupted.

a. 4.5 billion years b. 5700 years

4. In step c of experiment 3, the probe was used to measure uranium-238 in the tree. In step f of experiment 3, the probe was used to measure carbon-14 in the rock. In both steps (c and f), the probe reading was .

a. 100%, then decreasing with time. b. zero (0) . c. decreasing with time.

5. Uranium-238 must be used to measure the age of the rock, and not carbon-14, because:

a. The isotope carbon-14 did not exist when the rock was created.
b. rocks do not contain carbon-14, and even if they did, the carbon-14 would have likely decayed away prior to measuring the rock's age.
c. it is easier to measure uranium in rocks than it is carbon.

6. Based on your observations for experiment 3, and the answers to your questions above, should be used to determine the ages of once-living things, and should be used to determine the ages of rocks.

a. carbon-14; uranium-238 b. uranium-238; carbon-14 c. either can be used for both objects.

Experiment 4

1. Briefly explain why neither carbon-14 nor uranium-238 could be used to determine the ages of the last 4 items in data table 3.

Attachment:- radio-metric-dating-game.rar