Measuring the Age of Earth

the study of tree rings to determine the Earth's past, including climatic conditions

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  ice cores

• dendrochronology

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  half-life

• radioactive decay

Tags

NGSS.HS-ESS3-5

a core of ice that is drilled from a glacier or ice sheet; scientists study gases trapped inside

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  ice cores

• dendrochronology

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  half-life

• radioactive decay

the amount of time it takes for half of a radioactive isotope to decay

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  ice cores

• dendrochronology

• 
  

  half-life

• radioactive decay

Tags

NGSS.HS-PS1-8

the process by which an unstable atomic nucleus loses energy by radiation; directly related to half-life

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  ice cores

• dendrochronology

• 
  

  half-life

• radioactive decay

Tags

NGSS.HS-PS1-8

How do scientists use radioactive decay to determine the age of a rock or artifact?

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  by measuring the amount of sunlight the rock receives

• by measuring the ratio of radioactive to stable isotopes in the rock

• by analyzing the composition of the rock's minerals

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  by comparing the rock to other rocks in the same area

Tags

NGSS.HS-PS1-8

How could radiometric dating be used to determine the age of a fossilized bone?

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  by examining the bone's mineral composition

• by analyzing the bone's DNA sequence

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  by comparing the bone's shape to known fossils

• by measuring the ratio of isotopes in the bone

A sample of rock contains 50 percent of its original radioactive isotope and 50 percent of the stable isotope. If the half-life of the radioactive isotope is two million years, approximately how old is the rock?

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  2 million years old

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  1 million years old

• 500 thousand years old

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  250 thousand years old

Tags

NGSS.HS-PS1-8

If a sample of a radioactive isotope has a half-life of 10 years and initially contains 40 grams of the isotope, how much will remain after 30 years?

• 40 grams

• 20 grams

• 10 grams

• 5 grams

Tags

NGSS.HS-PS1-8