After incorporating radioactive atoms into reactant molecules, scientists can track where the atoms go by following their radioactivity.
One excellent example of this is the use of carbon-14 to determine the steps involved in photosynthesis in plants.
We have rocks from the Moon (brought back), meteorites, and rocks that we know came from Mars.
For others, all we are doing is getting a relative age, using things like the formation of craters and other features on a surface.*Note: This is an abbreviated Project Idea, without notes to start your background research, a specific list of materials, or a procedure for how to do the experiment.You can identify abbreviated Project Ideas by the asterisk at the end of the title.While that procedure is a great way to grasp the concept, it would certainly be a time-consuming and tedious process in the real world, even with samples of only 100 dice, which could scarcely be called a "large number." Furthermore, how many trials of rolling up to 100 dice over and over again—while accurately keeping track of the results—would you be willing to do by hand?The most motivated student will only get to a pretty small number of trials.