When I replied earlier re: how I would teach a 10 yr old the dive tables, it is important to note that I didn't say when and under what conditions I might do that. I just discussed what I consider a reasonable approach.
For the record, when my 10 year old grandson took the PADI Junior Open Water course a couple of months ago, I didn't do anything. The instructor is being paid to teach the course. Let them do the work. They know how to teach the material to a sufficient level to pass the exam.
Now, having said that, do I really think my grandson understands the tables? No. The new emphasis with PADI is on the eRDP - a calculator. The entire process of dive tables is condensed to one part of a single classroom session. Basically, it is discussed in enough depth to pass the test and buy a computer. But that's ok!
A Junior Open Water diver is restricted to diving with a certified parent/guardian or Dive Master/Instructor. More important, they are restricted to 40'. If you give them an aluminum 50, there is no way they can blow past the NDL and with just an hour of SIT they can keep diving all day long. They don't need to really understand the tables at this point. Their 'buddy' is responsible for getting it right. That's why they can't dive with the kid down the street!
Now, before everyone jumps up and down, how many adult OW students are really proficient with the tables - a week after the class is over? After they buy their computer? A year later? There's a reason PADI came out with the eRDP! For the most part, casual divers don't get the dive tables!
So, somewhere down the road, perhaps just in time for Junior Advanced Open Water (age 12), I would revisit the discussion re: dive tables. At that point they should be fully capable of learning and understanding the material. Maybe they have 100 dives or so. Perhaps the tables have been reintroduced over the years on a much more casual basis. Maybe one of the adults helps the young diver work it out when they log their dives.
I am a strong believer in the dive tables. They are far too important to be glossed over. But that a 10 year old isn't completely proficient doesn't concern me. There's plenty of time to get it done.
Richard