premise: if something causes something else then that something affects that something else sent2: as the rate of rocks cooling decreases , the crystal size of the rock will increase sent3: crystal size is a property of rocks and includes values of small / large sent4: rate is a kind of measurement of speed sent5: to slow / to slow down decreases speed sent6: if something affects something else then that something else indicates whether that something happened.
hypothesis: the radioactive isotope content of a rock can be used to identify the amount of time passed since a rock was formed