Briefly name and describe the THREE methods scientists commonly use to determine how long ago (in...

Question

Question

Briefly name and describe the THREE methods scientists commonly use to determine how long ago (in years) a currently extinct species lived.

Answer 1

Answer #1

Radiocarbon dating

Determin
es the age by measuring Carbon-14 content.
Half-life 5,730 ± 40 years, meaning that every 5,700 years or so the object loses half its carbon-14.
Carbon-14 (radiocarbon, naturally occurring, radioactive isotope) which is oxidized to carbon dioxide.
Green plants absorb this carbon dioxide having Carbon 14, so the content of carbon-14 molecules is continually replenished until the plant dies. Which is further passed onto the animals that eat those plants.
After death the amount of carbon-14 in the organic specimen decreases constantly as the molecules decay.

Potassium-argon dating

Potassium-40 (radioactive isotope) decays into argon-40.
Half-life -1.3 billion years, meaning that every 1.3 billion years or so the object loses half its Potassium-40. Far longer than that of carbon-14, allowing much older samples to be dated.
By knowing the normal value of Potassium 40 and the left value of Potassium 40 we can estimate the time period of the specimen.

Thermoluminescence

Thermoluminescence testing dates items to the last time they were heated in their time.
Principle- All objects absorb radiation from the environment.
Heating an item to 500 degrees Celsius or higher releases the trapped electrons, producing light. This light is measured to determine the last time the item was heated.

Answer 2

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