Based on carbon dating, how long ago did the tree die?

Based on carbon dating, how long ago did the tree die?

• A. 150 years ago
• B. 1500 years ago
• C. 15 years ago
• D. 1,500,000 years ago

Answer: (A)

Radiocarbon dating works by measuring the amount of carbon-14 left in a once-living organism to determine how long ago it died. Since carbon-14 decays over time with a half-life of about 5,730 years, this method is reliable for items roughly up to 50,000 years old. It isn’t useful for things millions of years old, and it isn’t very precise for very recent deaths because the change in carbon-14 over just a few decades is small. Among the options, a date of about 150 years ago falls within the workable dating window and is old enough to show a measurable difference from today’s atmospheric carbon-14. The 15 years ago option would be too recent to yield a confident radiocarbon date, and 1,500 years ago, while still dateable, is not as clearly distinguished in this context. A million years ago is far beyond what radiocarbon dating can handle. So 150 years ago is the best choice.

Radiocarbon dating works by measuring the amount of carbon-14 left in a once-living organism to determine how long ago it died. Since carbon-14 decays over time with a half-life of about 5,730 years, this method is reliable for items roughly up to 50,000 years old. It isn’t useful for things millions of years old, and it isn’t very precise for very recent deaths because the change in carbon-14 over just a few decades is small.

Among the options, a date of about 150 years ago falls within the workable dating window and is old enough to show a measurable difference from today’s atmospheric carbon-14. The 15 years ago option would be too recent to yield a confident radiocarbon date, and 1,500 years ago, while still dateable, is not as clearly distinguished in this context. A million years ago is far beyond what radiocarbon dating can handle. So 150 years ago is the best choice.