Later versions submerged the needle in liquid inside a closed container--these "damped" compasses were more stable, since the liquid kept the needle from swinging and shaking.

FORBES: No. 3 The Compass

Apparently the microwavable pad housed a chemical substance (manufactured by ADEKA) not quite stable enough to handle the heat, sparking a lengthy list of of cases where the liquid erupted from its container and provided an uncomfortable surprise to the poor soul embracing the creature's volcanic warmth.

ENGADGET: Exploding Hello Kitty toys recalled

This container is filled with 50kg of liquid argon and a thick layer of the element in its gas form.

BBC: Dark Matter: Experiment to shed light on dark particles

They fill the container with pure air made by evaporating liquid nitrogen and liquid oxygen, and add water vapour and some trace gases.

ECONOMIST: Climate change: Bubbling up | The

So we confiscate granny's shampoo at the airport because the half-empty container could hold 3.5 ounces of liquid.

CENTERFORSECURITYPOLICY: Betraying our dead