dunno, i made it for a project. was bored and stuff. for the density, drop the pennies on the raft until it sinks, to find out how dense the brand of seltzer you chose is. for the pH, hold the bottle with the mouse button over the cup (and a bit to the left as not to spill) while the mouse is down, press space to pour the seltzer, hold the pH strip (which starts out coloured neutral) in the seltzer for a second (or at least until it changes color) and then match it up with the scale. Finally, for the mass, do the same thing to pour the seltzer, and place the cup on the scale to see how much it weighs (the scale is at -0.1 originally, to balance the weight of the empty cup).
