While researching a topic, a student has taken the following notes:Radiocarbon dating measures the decay of carbon-14 isotopes in organic...
GMAT Expression of Ideas : (Expression) Questions
While researching a topic, a student has taken the following notes:
- Radiocarbon dating measures the decay of carbon-14 isotopes in organic materials to determine age
- This technique was developed by chemist Willard Libby in the 1940s
- Libby's method assumes that atmospheric carbon-14 levels remained constant throughout history
- Archaeologist Hans Suess proposed the reservoir effect theory to address dating inconsistencies
- According to Suess, carbon-14 levels vary between different environmental reservoirs due to local carbon cycling patterns
- Dendrochronologist Charles Wesley Ferguson developed tree-ring calibration methods
- Ferguson's approach uses annual tree-ring patterns to account for historical fluctuations in atmospheric carbon-14 levels
The student wants to compare how these two approaches address potential inaccuracies in radiocarbon dating. Which choice most effectively uses relevant information from the notes to accomplish this goal?
Both Suess and Ferguson have developed methods to improve the reliability of radiocarbon dating techniques.
Although Suess addresses environmental variation through reservoir effect theory, Ferguson uses tree-ring chronologies to calibrate for atmospheric changes over time.
Ferguson's dendrochronological calibration method was developed to address concerns about Libby's original radiocarbon dating assumptions.
Suess proposed the reservoir effect theory, whereas Ferguson developed an alternative approach using tree-ring analysis.
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Radiocarbon dating measures the decay of carbon-14 isotopes in organic materials to determine age" |
|
| "This technique was developed by chemist Willard Libby in the 1940s" |
|
| "Libby's method assumes that atmospheric carbon-14 levels remained constant throughout history" |
|
| "Archaeologist Hans Suess proposed the reservoir effect theory to address dating inconsistencies" |
|
| "According to Suess, carbon-14 levels vary between different environmental reservoirs due to local carbon cycling patterns" |
|
| "Dendrochronologist Charles Wesley Ferguson developed tree-ring calibration methods" |
|
| "Ferguson's approach uses annual tree-ring patterns to account for historical fluctuations in atmospheric carbon-14 levels" |
|
Provide Passage Architecture & Core Elements
Main Point: Two scientists, Suess and Ferguson, developed different approaches to improve radiocarbon dating accuracy by addressing different types of carbon-14 level variations that Libby's original method didn't account for.
Argument Flow: The notes establish that Libby's original radiocarbon dating method assumed constant atmospheric carbon-14 levels, but dating inconsistencies emerged. Two different scientists proposed solutions: Suess addressed spatial variation (different environments have different carbon-14 levels) through reservoir effect theory, while Ferguson addressed temporal variation (atmospheric carbon-14 levels change over time) through tree-ring calibration methods.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- The right answer should mention both Suess and Ferguson
- Explain what type of carbon-14 variation each scientist addresses (Suess focuses on environmental/spatial differences, Ferguson focuses on temporal/historical changes)
- Show how each approach tackles inaccuracies in radiocarbon dating
Both Suess and Ferguson have developed methods to improve the reliability of radiocarbon dating techniques.
✗ Incorrect
- Too vague - doesn't explain HOW each approach addresses inaccuracies or what specific aspect each scientist focuses on
Although Suess addresses environmental variation through reservoir effect theory, Ferguson uses tree-ring chronologies to calibrate for atmospheric changes over time.
✓ Correct
- Clearly contrasts the two approaches: Suess addresses environmental variation through reservoir effect theory while Ferguson uses tree-ring chronologies to calibrate for atmospheric changes over time
- Shows exactly how each method tackles different types of carbon-14 variation problems
Ferguson's dendrochronological calibration method was developed to address concerns about Libby's original radiocarbon dating assumptions.
✗ Incorrect
- Only discusses Ferguson's method, ignoring Suess entirely
- Fails to provide the required comparison
Suess proposed the reservoir effect theory, whereas Ferguson developed an alternative approach using tree-ring analysis.
✗ Incorrect
- Simply states what each scientist proposed without explaining how their approaches address dating inaccuracies or showing the connection between their methods and solving the accuracy problem