J's second experiment from his Disgusting Science Kit was to recreate how the bodies digestion system works using a balloon.
First he tore up a piece of bread and forced them into the neck of the balloon through the "esophagus".
Then he used a pipette to pour vinegar (stomach acid) into the balloon along with the bread.
Then he squished and squashed everything together
Then his balloon became the intestinal system and he squeezed his bread concoction through the neck of the balloon (the intestines) and out.
Gross I know, but it's a fact of life, and this was a very easy way to give him a quick idea of how the digestive system works.