some of the new students told me that they're not very sure that Aikido really works without too much strength.. what would you do if you were told that?
When I go rockclimbing I get the best feedback for how effective my technique is after my arms are too tired to do all the work.
What about trying it with aikido? Get them to do a whole heap of pushups until they've got noodles for arms. Then
tell them to deflect an attack.