Half-life Class Notes and Forensic Lab

In Chemistry class today, we took notes on half-life and prepared for our Forensic Lab. While taking our notes, I surprisingly remembered several things that I believe I learned in 8th grade. However, I did learn a couple new and helpful things. First, I did not know that the decayed part of a half-life sample becomes stable. I simply thought it just disappeared or became a totally different element. In addition, although it sounds obvious, I didn't realize that you could quickly calculate half-life questions by using exponents in the denominator of the fraction. Previously, I was dreading the thought of dividing a sample multiple times to find the resulting amount of mass in a sample. Now that I know this trick, I will be able to calculate the half-life and amount of samples quickly, decreasing errors.

After completing notes, we cut up a piece of printed paper into 576 pieces for our Forensic Lab. Since we didn't have time to finish the lab in class, I performed it at home. To begin, I took 567 "atoms "(pieces of paper), shook them up, dumped them out, and counted the pieces with their white side up. These pieces represented the number of atoms that had decayed. I then put the "decayed" atoms in a bag and placed the rest of the pieces of paper facing the other way (representing the number of atoms that remained in the sample) back in the cup and repeated these steps 5 more times. Overall, the experiment gave me a visual and physical representation of half-life that reinforced my understanding of the concept. I plan on using the practice problems on the website that I posted a link to in order to practice more half-life questions before my next test. I also included pictures from the Forensic Lab I performed today.

Link to half-life practice questions