CONCLUSIONS:

What might have gone wrong? If the triple beam balance was used, the results might have been different and perhaps more accurate. The electronic scale was accurate to a certain amount, however there was a small percentage (less than 1%) degree of error.
 
Was there an error in your work that you could fix for next time? No, other than using a triple beam balance might have given me a more accurate reading for massing the stones.
 
How does your new learning fit with your background reading? If acid rain falls in Collingwood, it could erode some of the limestone that is underneath Collingwood and the Escarpment.  It could destroy the town and ski hills.