Hello Colin,
Welcome to the Forum, I hope we will hear a lot more from you now you have found us, but particularly, I hope we will also hear from some of your Cub Scouts with their own thoughts and ideas on knotting.
It is great that you intend to introduce these youngsters to the world of knots, but more importantly, I hope you will primarily introduce them to the world of string - knots simply being the means of putting string to work. Learning to tie knots without a use is a bit like learning to sing notes but never learning any songs. Teaching the use of string today is shatteringly hard. What did we used to use string and knots for, that is not now performed by Velcro, Sellotape, double sided tape, hotmelt glue gun, cable ties etc. etc. etc.
Show a child of today a piece of string and a knot and you are likely to be met with a look that says “Interesting history lesson, but what use is it today”. You might as well be showing them a 20 book encyclopedia and expect them to use it instead of using Wikipedia, or to use two cocoa tins and a piece of string instead of their mobile phones.
I put it to you that the greatest challenge you face is to find uses for string that lead to these new citizens deciding that it is really useful to have a piece of good string in their pocket, only then will they actively want to learn some good knots that let them use the string to best advantage. How many people do you know that have a piece of string in their pocket or purse? I would hazard a guess that not only is the number very low, but that you yourself do not have a piece about your person. If this is the case, could the reason be because you have no need or use for it? Teaching a youngster a knot to tie up their Pony is of little use when they ride a BMX.
Having made the point that the task you face is a hard one, I do not believe that the challenge is impossible, nor is it a pointless exercise, it just means that for your initiative to be effective, you need to start to ‘THINK STRING’ before you start to teach knots. Might I suggest that you equip yourself with a 1m length of high quality 2mm nylon braid (price 3p per metre) and do likewise for each of your students. Then learn and teach two knots.
The first is the Parcel Knot or Packers Knot http://commons.wikimedia.org/wiki/Image:Packers_knot.png
The second is the slipped or fixed Strangle (or double strangle) loop http://igkt.net/sm/index.php?topic=616.0
These two knots are easy to tie, easy to remember and very very easy to use, but most of all, they are self holding knots. They can function as a second pair of hands to hold something in place for you while you fix something else. Then the challenge starts - ask your students to use their string during the week and see how many uses they found for it - did the knots work and if not why not? Then when you have yourself and your group thinking about ways to use string, then you can start to bring in specialist knots that will do specific jobs perfectly. All the time ask - was string or Velcro(or Selotape etc) best and why (not forgetting of course, that string is in your pocket but it is unlikely that you have a roll of Sellotape or Velcro handy and you can’t untie Sellotape).
Finally a request - if you start this process - PLEASE keep a log here of how it is progressing, what you learnt and what your group learnt.
But most important - put a piece of string in your pocket and ‘THINK STRING’.