Background: Where do the decimals come from in the atomic mass number?
Atomic numbers are nice even numbers say 1,2, 3, 4 and 57, 71….The atomic mass numbers are not so nice, often with decimals. This lab is designed to answer that question. The short answer, because the atomic number is the average of all the isotopes of each atom found in the universe. In this worksheet we simulate this averaging with candy.
Materials: 1 Triple Balance, and a variety of candies or pastas
1. Measure out 10 candy corns and 3 pumpkin candy corns. These are two “Isotopes” of Candy Corn.
2. Find the mass of the 10 candy corns and record it in the table. Do the same with the pumpkin candy corns.
3. Find the mass of 1 piece of candy corn of each type.
4. Count up the total number of pieces of candy of both types.
5. Calculate the percentage of each type candy corn represents compared to the whole. In the example there were ten candy corns and 3 pumpkin candy corns making a total of 13 candies. So its 10/13 or 77% for regular candy corns and 3/13 for 33%.
6. Multiply that percentage times the mass of one piece. Do this for each type candy.
7. Finally add the last column up to find the atomic mass