Understanding Radioactive Decay
* Half-life: U-235 decays radioactively, meaning it transforms into other elements over time. The half-life of U-235 is approximately 703.8 million years. This means that every 703.8 million years, the amount of U-235 in a sample reduces by half.
Calculations
1. Determine the number of half-lives: Since the rock went from 1500 atoms to 750 atoms, the amount of U-235 has been halved. This means one half-life has occurred.
2. Calculate the age:
* One half-life of U-235 is 703.8 million years.
* Therefore, the rock is approximately 703.8 million years old.
Important Note: This calculation assumes that the rock has not been disturbed or undergone other processes that could alter the amount of U-235 present.
