# Radioactive dating lab pennies

Any **pennies** that land tails up are assumed to have "**radioactively** decayed" on this toss.

Stack the tails-up **pennies** into a column on the far side of the table.

For example, you can compare your graphs to that of a straight line, y = mx b, with y being the number of *pennies* in a column and x being the toss number of the column.

Obviously, you will have to see if you can find any values of m and b which fit your data.

the chance that an atom will decay in the next second is unaffected by the fact that it did not decay a second ago.

Clearly the number of atoms decaying in one second depends on the number of atoms you start with, but the chance of any individual atom decaying in a given time period is always the same.

Repeat the process until all **pennies** have landed tails up.

If no *pennies* are tails up on a particular toss, leave the column corresponding to that toss empty.

The **lab** procedure to mimic **radioactive** decay is simple. Toss the **pennies** onto a table surface or the floor.

Return the remaining heads up **pennies** to the box and toss them again onto the table surface.

Remove the tails up *pennies* and stack them into a second column right beside the first column.

Tupperware container (with top)*, 100 **pennies**, plastic cup, graph paper (one per student), rulers, handout (attached, one for each student), Periodic Table, tables of isotopic decay types and half-lives*I have found it works well to identify the isotope with a post-it on the top of each groups Tupperware container. These **pennies** represent those that have undergone **radioactive** decay. Count the heads up **pennies** that remain in the original container and record the number in the data table. Repeat steps 1-3 with the remaining **pennies** for 3 additional half-life periods.

Common isotopes to use are carbon-14, iodine-131, cobalt-60, hydrogen-3, strontium-90, and uranium-238, though any *radioactive* isotope with a known decay type and half-life can be used. Data: Data Analysis: On the graph paper provided, graph mass vs. Plot all points then connect them with line of best fit. Conclusions: 1) Write the nuclear decay equation for the radioisotope that you were given.