I was in and out of the workshop this afternoon and when I returned one time, Martin had a piece of wood in the bench vice and was trying to turn it to observe, and ultimately try to break the wood. Dad counseled him that it is indeed important work, that we should try different kinds of materials, but that we should also wear some goggles in case a piece flew towards his eye.
So, he tried odd pieces of things from the garbage – vinyl, wood, sticks and watched deformation and shear at work!