6.The age of the Earth can be estimated in many ways. Which statement below is most accurate (remember thatuniformitarian calculations involve looking at the thickness and type of sedimentary rocks, and similar things, but doNOT include radiometric dating or counting of annual layers)?
A) Annual-layer counting shows that the Earth is more than about 100 million years old.B) Annual-layer counting shows that the Earth is more than about 100 thousand years old, uniformitarian calculationsshow that the Earth is more than about 100 million years old, but we don’t know how to estimate how much more than100 million years the Earth is.
Points Earned:
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Points Earned:
1.0/1.0
Points Earned:
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4/6/15 12:53 PM
RockOn #10
Page 3 of 8
C) Annual-layer counting shows that the Earth is more than about 100 thousand years old, uniformitarian calculationsshow that the Earth is more than about 100 million years old, and radiometric techniques tell us how old the Earth is.D) Annual-layer counting shows that the Earth is 4.6 billion years old.E) Uniformitarian calculations show that the Earth is 4.6 billion years old.
7.One practical radioactive system used to date lava flows involves:
A) The gas argon-40, which decays to the gas potassium-40.B) The gas argon-40, which decays to solid potassium-40.C) The solid potassium-40, which decays to solid argon-40.D) The solid potassium-40, which decays to the gas argon-40.E) The solid potassium-40, which decays to the solid moosemossium-41.Feedback: Potassium-40 is common in solid minerals, and decays to produce the gas argon-40. And despite his greatcontributions to humanity, no one has named an isotope after moose moss (the favorite food of Thidwick, for you Dr.Suess fans).
8.You start with 800 parent atoms of a particular radioactive type, which decays to give stable offspring. You wait justlong enough for two half lives to pass. You should expect to have how many parent atoms remaining (on average):
9.