This activity was used with a gifted summer session.  The students were rising 2nd-4th graders. 

The basic idea was that students moved in small groups through 8 different caches.  At each cache, they solved a puzzle that gave them one single digit number.  Once they had all 8  numbers, they went to a final cache.  This cache had two locks on it, each with 4 digits.  They used the 8 numbers they had discovered at the other caches to open the locks and get the “treasure.”  I used a pirate theme, but I actually think a secret agent theme would work even better.

Materials Needed:

• Cache Hint Cards
• One box with space for two locks (my dad made mine, but I’ve seen some toolboxes that would work)
• Two locks with 4 numbers each on them
• See the slide show below for pics of the contents of each cache:

• You will also need one of these items per group: 
  • “Invisible Ink” kit  from Dollar Tree (consist of one pen, and one blacklight flashlight).  Students only need the flashlight.
  • Morse Code Cards
  • Geocaching Code Wheel (from Geocacher University)
  • Answer Sheet

Students first introduced to the activity of geocaching.  They were also given some things to think about when they were solving the puzzles.  I used this ActivBoard flipchart:

Flipchart

Then in groups of 2 or 3, students moved through the different caches solving problems.  When they were completely done, they had the code to open the locks on the final treasure. 

Things I learned and would do differently next time:

• It would work better to have a demo lock to show in the beginning to teach students how to unlock and relock combo locks.
• All the groups for one set of students finished at the same time.  There was a run to the treasure box.  I think next time there will be some rules to this part.