The non-science of Fringe: Entrada

Fringe : Season 3 : Episode 8 : “Entrada”

The countdown to extraction.

The countdown to extraction.

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).

This episode is debunked at Polite Dissent, and you can read more about it at Fox, IMDb and the A.V. Club.

Random thoughts

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:

\frac { 115 ~ \text {kg} ~ * ~ 1000 ~ \text {g kg}^{-1} } {58.443 ~ \text {g mol}^{-1}} \simeq 1967 ~ \text {mol}

\frac { 1967 ~ \text {mol} } {2000 ~ \text {dm}^{3} } \simeq 0.98 ~ \text {mol dm}^{-3}

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.


2 Responses to The non-science of Fringe: Entrada

  1. Daedalus says:

    I was under the impression that Sensory Deprivation tanks used Epsom Salt (hydrated Magnesium Sulphate) (yes, I am British). JJA and his writers should know better: some of them probably have used SD tanks.

  2. John says:

    I believe that “real” tanks do use Epsom salts – perhaps Walternate’s lab didn’t have any around and they had to pilfer rock salt from the snow control station. ;)

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: