Use common sense analogies like example given by ZZJASEZZ---to explain effects on forks when load weight moves away from heel towards toe. How about why is a ladder more stable on the bottom rung and as you climb to the top, it becomes less stable?

Picture getting on a diving board....."Why does the board begin to bend as you move towards end?

The explaination of the lever-fulcrum principle works good.

Use simple common sense analogies and use terminology that is going to make sense to a "Green" operator.

This may come as a shock to some trainers, but how many M.I.T. students do you think operate forklifts: The technical "JARGON" you hear will be way over their heads and they will not have a clue what you are saying.

They will in no way be able to calculate all the figures unless they have scale to weigh their loads with. Most operators would not retain this info even after you show them.