Frazz by Jef Mallett for September 16, 2014

Maybe if she keeps on inSistine, her teacher will give in and let her change her book to a biography of Michelangelo.

I believe the U.S. spent a fortune developing these pens. The Russians just used pencils.

How primitive…the kids haven’t been given tablets?

Wait a minute…are you saying that pencils work even when upside down?

Fisher Space Pens are made in my home town, Boulder City, Nevada. Puddle is right (I had no idea there was a need for a Snopes article on them!) Way cool invention, I love my space pen. One cool anecdote about them: during a moon landing, a lever for a switch that allowed the lander to ascend back up to the orbiting ship broke off. The astronauts were able to use the housing of their space pen to substitute for the lever, allowing the switch to be flipped. Space Pen saves the day (and a couple of lives)!

Pure O2 at normal atmospheric pressure is unhealthy in the long term and very dangerous, as witness the Apollo 11 fire on the pad..However, in space, the spacecraft up through Apollo used 100% O2 at about 150mm Hg pressure — or about 3 PSI, one-fifth of an atmosphere. The reduced cabin pressure meant the spacecraft structure was easier and cheaper to build. The shuttle and the ISS both use a more air-like mix of O2 and N2 at close to atmospheric pressure. See http://en.wikipedia.org/wiki/Life_support_system for a lot of discussion on the matter..The pure O2 (at reduced cabin pressure) on Mercury, Gemini, and Apollo gave the lungs 150mm Hg partial pressure of O2 — the same 150mm Hg partial pressure they get at sea level with a 20%/80% mix of oxygen/nitrogen at a total pressure of 750mm Hg. (All numbers have been rounded a bit)..The converse is true for exceeding 1 atmosphere. You want 150mm Hg partial pressure of O2, so deep divers use a mix of oxygen and helium for long term dives or submersible habitation. At around 120 feet depth, you have 4 atmospheres of pressure, so to get 150mm partial pressure of O2, you need about a 5%/95% mix of oxygen and helium. The lungs use the 5% O2 at that pressure just like the 20% O2 at sea level.

The universe tends to maximize toward entropy.

100% O2 at normal atmospheric pressure is extremely toxic to infants, especially newborns, more especially preemies. Have to watch the O2 concentration in incubators to prevent blindness and respiratory damage..Not as nasty for adults, though I wouldn’t want to breath it for weeks on end. As previously mentioned, the Apollo astronauts were on 100% O2 at 3 psi for the duration of there missions, 3 days each way plus time on the surface. I don’t know if would have been problematic at 15 psi instead of 3..My personal longest on 100% was in the altitude chamber for periodic training. We pre-breathed 100% O2 for 30-45 minutes to reduce the chances of bends, then spent another 2 hours in the chamber at various pressure altitudes. So my personal max time on 100% O2 is about 3 hours, most of which was at pressure altitudes of 15,000 to 40,000 feet.

@puddleglum1066

www.spacepen.com They are all I use. Mostly because they don’t “explode” in the car in the Texas heat. They also don’t freeze up in Minnesota.