Fringe : Season 3 : Episode 8 : “Entrada”
The Earth-1 vs. Earth-2 conflict starts to accelerate this week as the two Olivias return to their original sides. It’s another overarching plot-driven episode, meaning that there isn’t really any science to talk about (here’s hoping they get The Machine working soon).
If Peter is required for The Machine to work, presumably Olivia-2 couldn’t just shoot him – in which case he could have bluffed his way out of the apartment stand-off.
Not much else to talk about this week (I’m not going to touch quantum entanglement), so let’s do an entirely unnecessary calculation regarding the sensory deprivation tank. It looks to be about 1 m wide by 2 m long by 1 m deep, giving it a volume of 2 m3, and Olivia pours what looks like five 23 kg bags of rock salt into it for a total of 115 kg. The solubility of rock salt (which we’ll assume is pure NaCl) is 359 g dm-3 at 25 °C, which means that a maximum of 718 kg could have been dissolved and that Olivia’s solution is nowhere near saturated. We can estimate the concentration of NaCl with a simple calculation:
Seawater has an average salt concentration of approximately 0.559 mol dm-3 (~ 5.7 mol dm-3 in the Dead Sea), making the solution salty enough to improve Olivia’s buoyancy only a little.