294
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 20 Jun 2024
294 points (97.1% liked)
Cool Guides
4468 readers
4 users here now
Rules for Posting Guides on Our Community
1. Defining a Guide Guides are comprehensive reference materials, how-tos, or comparison tables. A guide must be well-organized both in content and layout. Information should be easily accessible without unnecessary navigation. Guides can include flowcharts, step-by-step instructions, or visual references that compare different elements side by side.
2. Infographic Guidelines Infographics are permitted if they are educational and informative. They should aim to convey complex information visually and clearly. However, infographics that primarily serve as visual essays without structured guidance will be subject to removal.
3. Grey Area Moderators may use discretion when deciding to remove posts. If in doubt, message us or use downvotes for content you find inappropriate.
4. Source Attribution If you know the original source of a guide, share it in the comments to credit the creators.
5. Diverse Content To keep our community engaging, avoid saturating the feed with similar topics. Excessive posts on a single topic may be moderated to maintain diversity.
6. Verify in Comments Always check the comments for additional insights or corrections. Moderators rely on community expertise for accuracy.
Community Guidelines
-
Direct Image Links Only Only direct links to .png, .jpg, and .jpeg image formats are permitted.
-
Educational Infographics Only Infographics must aim to educate and inform with structured content. Purely narrative or non-informative infographics may be removed.
-
Serious Guides Only Nonserious or comedy-based guides will be removed.
-
No Harmful Content Guides promoting dangerous or harmful activities/materials will be removed. This includes content intended to cause harm to others.
By following these rules, we can maintain a diverse and informative community. If you have any questions or concerns, feel free to reach out to the moderators. Thank you for contributing responsibly!
founded 1 year ago
MODERATORS
Altitude reduced the density of air as whole. The graphic is about changes in composition while density should remain similar, meaning if oxygen is low, something else (e.g. carbon mono-/dioxide) is high. So I wonder how this compares.
Partial pressure of the gases you breathe is what matters though, that's why astronauts could breathe pure oxygen for days during the Mercury/Gemini/Apollo missions and be fine (as long as there's no fire :/ ).
Just to clarify, the partial pressure of oxygen in the atmosphere is about 3 PSI. The partial pressure of Nitrogen in the atmosphere is about 10 PSI.
Fire risk is also related to the partial pressure of the gas. 100% oxygen is not actually a problem, so long as the partial pressure of that oxygen is low. The partial pressure of oxygen in the Apollo 1 capsule was about 16.7 PSI.
Astronauts still use 100% oxygen in space suits pressurized to about 5PSI.
I had always assumed they just compensated with oxygen pressure to match atmospheric partial oxygen pressure, but I checked and indeed you're right, but it was only that high an oxgen pressure for testing purposes on the ground. Once in flight, they would have dropped it to 5 PSI. It also makes sense as to why that Apollo 1 fire was so violent. Thanks for that learning opportunity ! :)
I was actually more referring to the chart implying that low oxygen means higher concentration of toxic gases