breaking down of a stable isotope into a radioactive isotope

breaking down of a radioactive isotope into a stable isotope

protons breaking down over time

electrons breaking down over time

element with a different number of protons than usual

element with a different number of electrons than usual

element with a different number of neutrons than usual

a radioactive element

time for half a radioactive isotope to decay

half the time for a radioactive isotope to decay

time for half the protons to leave a radioactive element

time for half of an element to decay

using rate of decay to estimate age

time when decay began

time when radioactivity began

time when half life ends

record of earth's past

history of earth broken into smaller divisions

relative age of fossils

age of dirt and rocks in a particular area

remains of a once living organism

bones, teeth, and hard parts of a once living organism

evidence that a once living organism was in an area

preserved remains or evidence of a once living organism

minerals replaced living substances creating stone

studying fossils to discover earth's history

soft parts of an organism being preserved via mineralization

when living tissue is replaced with hard dirt

short lived, widely spread preserved organisms

fossils particular to a given location

fossils particular to a given climate

fossils particular to a given sediment type

study of the layers of rocks

study of the age of fossils

study of the process of fossilization

study of trace fossils

top layers of rock newer; lower layers of rock older

top layers of rock older; lower layers of rock newer

fossils in new rock are older

fossils in old rock are newer than the age of the rock

rock of the same time continues in a horizontal plane

rock of the same time continues in all directions

rock of similar layers appears smooth

rock of lower layers will always be beneath upper layers

rock laid in horizontal layers will remain in horizontal layers unless disturbed

rock is laid horizontally unless an earthquake occurs

original rock is never in any position but horizontal

sedimentary rock is laid horizontally, but not all other types of rock

if something cuts across a layer of rock, it must be younger than that rock

rock on each side of a cut can be lined up and used to date the cut

rock laid in an upper layer is older than a lower layer

rock laid in an upper layer is younger than a lower layer

break or gap in the rock record

different types of rock found within a single sample of sediment

rock which contains fossils

rock which has had water flow through it