Absolute dating 6th

Absolute Age

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Absolute Age

•Absolute Age—the number age of a rock or an objectExample—Mr. Choi is 14 years old.

Estimating how much time has passed

•Let’s say this timer on the left takes 1 minute for all the sand to drop down to the bottom. If half the sand has fallen

through, how much time has passed?

Estimating how much time has passed

•Let’s say this timer on the left takes 10 minute for all the sand to drop down to the bottom. If half the sand has fallen

through, how much time has passed?

Estimating how much time has passed

•Let’s say this timer on the left takes 4 minute for all the sand to drop down to the bottom. If ¾ (3 quarters) the sand

has fallen through, how much time has passed?

Estimating Earth’s age and other fossils

• Just like a glass timer, certain things on Earth have a “timer” in them that tells us how much time has passed. This has helped us determine the age of

the Earth and other fossils.

Absolute Age• Radioactive Decay—the process where an unstable element becomes stableExample: Radioactive Uranium Stable Lead

Radioactive Carbon Stable Nitrogen

Absolute Age• Radiometric dating—looks at how much radioactive decay has occurred in an object to determine the age.

Drawing out Radioactive Decay

Drawing out Radioactive Decay

Drawing out Radioactive Decay

250,000 years old

Drawing out Radioactive Decay

250,000 years old

500,000 years old

Drawing out Radioactive Decay

750,000 years old

250,000 years

250,000 years

250,000 years

250,000 years old

500,000 years old