Fruit Loop Isotopes Lab

Question: Why are atomic masses not whole numbers?

Materials:

• 7 weighing boats that will represent the nucleus
• 21 fruit loops in one color that will represent the protons
• 60 fruit loops in another color that will represent the neutrons
• Balance

Procedure:

1. Make the following 7 atoms as follows
        a. Five will have 3 protons and 10 neutrons (These will be referred to as A-10)
        b. Two will have 3 protons and 5 neutrons (These will be referred to as A-5)
2. Weigh each atom (do not include the weighing boat in the weight)

   Atom	# of protons	# of neutrons	Mass (grams)
   1
   2
   3
   4
   5
   6
   7

3. 3. Find the average mass of your atom
        a. Find the total mass of all 7 atoms __________________
        b. Find the average mass (part a 7) _______________
4. Find the average mass of an isotope
        a. Find the total mass of all the A-10 atoms _________
        b. Find the average mass of the A-10 atoms ______
5. Find the average mass of the other isotope
        a. Find the total mass of the 2 atoms that have 5 neutrons _________
        b. Find the average mass of the 2 atoms that have 5 neutrons ______
6. Find the average of 5b and 4b ____________________
7. Does the answer to number 6 match the answer to number 3b? Why not?
8. How could you use the average masses of A-10 and A-5 to get the same average mass as in 3b?