* You can show that water supports heavy objects by hanging a brick from a Newton meter then lowering the brick slowly into a bucket of water while watching the scale. Then hypothesise about why beached whales don't survive.
* Pupils can explore the range of movements of their own arms easily, and link manual dexterity to the opposable thumb. The range or limitation of joint movement and the antagonistic arrangement of our skeletal muscles can be explored using model skeletons. At KS3 or 4, the relative positions of the pivot, load and effort in the body's different levers could be linked to the biomechanics of the octopus.
* Work on camouflage, warning colours and mimicry can extend the observations of rapid colour adaptation shown by the octopus too.