Every reaction in the box is a real one, simplified, and each discovery says what really happens. One cell is a pinch of stuff and reactions are rolled as chances rather than real rates. Falling things speed up as they fall, and liquid finds one level through a U-bend, with a lighter liquid on top counted by its weight, but the fall rate and flow speed are set for the screen, not measured, and gases have no pressure. Electricity is on or off: the two ends of a battery joined through metal or a liquid that conducts carry current, with no voltage to read and a battery that never runs down, and a short circuit heats each metal by its real resistivity. Apart from water melting and boiling and lava setting, every material holds heat the same way. Each reaction the game can announce is checked by a test before it ships.