Half-life is a totally random number.

Question

Question 10
10. Why do you have to we use carbon-14 to measure the half-life of a decaying tree?(1 point)
Responses

All once-living things contain uranium-238 and the amount begins to increase when the tree dies.
All once-living things contain uranium-238 and the amount begins to increase when the tree dies.

All once-living things contain carbon-14 and the amount begins to increase when the tree dies.
All once-living things contain carbon-14 and the amount begins to increase when the tree dies.

All once-living things contain uranium-238 and the amount begins to decrease when the tree dies.
All once-living things contain uranium-238 and the amount begins to decrease when the tree dies.

All once-living things contain carbon-14 and the amount begins to decrease when the tree dies.
All once-living things contain carbon-14 and the amount begins to decrease when the tree dies.
Question 11
11. Answer these 3 questions.



> What percent of the element is left at the 1st half-life?



>> What percent of the element is left at the 2nd half-life?



>> What percent of the element is left at the 3rd half-life?

(1 point)
Responses

1st: 50-60% 2nd: 24-30% 3rd: 12-15%
1st: 50-60% 2nd: 24-30% 3rd: 12-15%

1st: 70-80% 2nd: 50-60% 3rd: 24-30%
1st: 70-80% 2nd: 50-60% 3rd: 24-30%

1st: 12-15% 2nd: 24-30% 3rd: 50-60%
1st: 12-15% 2nd: 24-30% 3rd: 50-60%

1st: 24-30% 2nd: 50-60% 3rd: 70-80%
1st: 24-30% 2nd: 50-60% 3rd: 70-80%
Question 12
12. Why do we use uranium-238 to measure the half-life of a rock?(1 point)
Responses

All non-living things contain uranium-238 and the amount begins to increase when the rock comes to the surface.
All non-living things contain uranium-238 and the amount begins to increase when the rock comes to the surface.

All non-living things contain carbon-14 and the amount begins to increase when the rock comes to the surface.
All non-living things contain carbon-14 and the amount begins to increase when the rock comes to the surface.

All non-living things contain carbon-14 and the amount begins to decrease when the rock comes to the surface.
All non-living things contain carbon-14 and the amount begins to decrease when the rock comes to the surface.

All non-living things contain uranium-238 and the amount begins to decrease when the rock comes to the surface.
All non-living things contain uranium-238 and the amount begins to decrease when the rock comes to the surface.
Question 13
13. Answer these 3 questions.



> What percent of the element is left at the 1st half-life?



>> What percent of the element is left at the 2nd half-life?



>>> What percent of the element is left at the 3rd half-life?

(1 point)
Responses

1st: 12-15% 2nd: 24-30% 3rd: 50-60%
1st: 12-15% 2nd: 24-30% 3rd: 50-60%

1st: 50-60% 2nd: 24-30% 3rd: 12-15%
1st: 50-60% 2nd: 24-30% 3rd: 12-15%

1st: 24-30% 2nd: 50-60% 3rd: 70-80%
1st: 24-30% 2nd: 50-60% 3rd: 70-80%

1st: 70-80% 2nd: 50-60% 3rd: 24-30%
1st: 70-80% 2nd: 50-60% 3rd: 24-30%
Question 14
14. Watch Video #3 to answer questions #14-15.

Determine the age of the wooden cup. Should you use Carbon-14 or Uranium-238 and why?(1 point)
Responses

1,000-1,040 years; Carbon-14; because wood was once living.
1,000-1,040 years; Carbon-14; because wood was once living.

700-750 Million Years; Carbon-14; because rock is a living stone.
700-750 Million Years; Carbon-14; because rock is a living stone.

1,000-1,040 years; Uranium-238; because wood was once living.
1,000-1,040 years; Uranium-238; because wood was once living.

700-750 Million Years; Uranium-238; because rock is non-living.
700-750 Million Years; Uranium-238; because rock is non-living.
Question 15
15. Determine the age of rock #4. Should you use Carbon-14 or Uranium-238 and why?(1 point)
Responses

1,000-1,040 years; Carbon-14; because wood was once living
1,000-1,040 years; Carbon-14; because wood was once living

1,000-1,040 years; Uranium-238; because wood was once living
1,000-1,040 years; Uranium-238; because wood was once living

700-750 Million Years; Uranium-238; because rock is non-living
700-750 Million Years; Uranium-238; because rock is non-living

700-750 Million Years; Carbon-14; because rock is a living stone
700-750 Million Years; Carbon-14; because rock is a living stone
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Answer 1

Here are the answers to the questions based on the principles of radiocarbon dating and uranium dating:

Question 10:

• Correct Response: All once-living things contain carbon-14 and the amount begins to decrease when the tree dies.

Question 11:

• Correct Response: 1st: 50-60% 2nd: 24-30% 3rd: 12-15%

Question 12:

• Correct Response: All non-living things contain uranium-238 and the amount begins to decrease when the rock comes to the surface.

Question 13:

• Correct Response: 1st: 50-60% 2nd: 24-30% 3rd: 12-15%

Question 14:

• Correct Response: 1,000-1,040 years; Carbon-14; because wood was once living.

Question 15:

• Correct Response: 700-750 Million Years; Uranium-238; because rock is non-living.

If you need further explanations or clarifications on these topics, feel free to ask!