25.2 the fossil record Flashcards
1
Q
radiometric dating
A
based n radioactive isotopes
2
Q
half life
A
time it take for 50% of the parent isotope to decay
3
Q
how od you date with carbon
A
when organisms die, they have carbon12 and radioactive carbon 14. after they die, C12 stays the same and C14 decays into nitrogen. when the fossil is found, compare ratio of C12 to C14 to see how old it is
4
Q
how to date in sedimentary rock
A
find age of layers and then use it as reference
5
Q
magnetism date how
A
when volcanic and sedimentary rocks are still liquid, the particles align to the magnetic field, when it hardens, its stuck like that. finding when the magnetic fields shifts can give a relative age
