Train a pen lid to dive, with Jill (cartesian diver)
Jill has been VERY busy during lockdown, teaching Bob, the pen lid, to dive on command (or possibly using the science behind density and buoyancy to make her own cartesian diver).
Jill has been VERY busy during lockdown, teaching Bob, the pen lid, to dive on command (or possibly using the science behind density and buoyancy to make her own cartesian diver).
