Demonstrate radioactive decay using Skittles.
Demonstrating the half-life of a radioactive isotope is helpful when introducing students to the process of radioactive decay, which occurs when an unstable atom, such as Uranium-238, loses energy by emitting ionizing particles. An example of this is a carbon-14 atom, which emits radiation in the form of a beta particle, a gamma ray and an antineutrino to transform into a nitrogen-14 atom. Radiocarbon dating uses this knowledge of carbon-14, which has a half-life of 5,730 years, to date geological and archaeological samples. You can demonstrate the half-life of a radioactive isotope cheaply with a bag and a few handfuls of Skittles and jelly beans.
Instructions
1. Place 64 Skittles in a bag. Each Skittle represents a parent atom. You can also use other objects that also have a 50/50 chance of resting in a specific state when shaken in a bag, such as coins or M&Ms.
2. Create a chart on a piece of paper or a chalkboard with columns for "Shake #", "# of half-lives", "Total parent atoms" and "Total daughter atoms." You will use this to track the radioactive decay process.
3. Enter values on the first row of your chart. For example, using 64 Skittles, write 0 under "Shake #", 0 under "# of half-lives", 64 under "Total parent atoms" and 0 under "Total daughter atoms."
4. Shake the bag for 5 seconds and then release the candy on to a table.
5. Count the amount of Skittles on the table with the "S" showing face up. Remove these from the others. If you are using coins, remove the ones that show heads face up. These represent the parent atoms that decayed, or transmuted, into a daughter element, which is a new element. Approximately half the Skittles should now be gone.
6. Place the remaining Skittles back in the bag and replace the removed Skittles with an equal amount of jellybeans. For example, if you removed 33 Skittles, you will now have 31 Skittles and 33 jellybeans in the bag.
7. Write the new values on your chart in the second row. For example, if you removed 33 Skittles, write 1 under "Shake #", 1 under "# of half-lives", 31 under "Total parent atoms" and 33 under "Total daughter atoms."
8. Shake the bag for 5 seconds again and release the candy on to a table.
9. Repeat the above steps until all the parent atoms are gone. Remove the Skittles that have an "S" showing face up, replace them with an equal number of jellybeans and write your new values on the chart. Each time you shake the bag represents a half-life of the Skittles. You should be removing approximately 50 percent of the remaining Skittles during each iteration. This follows a 1/2 * 1/2 * 1/2 pattern in relation to the initial amount of Skittles, which demonstrates the half-life process of radioactive decay.
Tags: parent atoms, radioactive decay, under Total, daughter atoms, removed Skittles
