Wikipedia:Reference desk/Archives/Miscellaneous/2021 January 22

= January 22 =

Humectants and several hours
On this very helpful article it says Humectants absorb water. They can absorb this water from the air and moisturize the skin when the humidity is greater than 70%, but more commonly they draw water from the dermis into the epidermis, making skin dryer. Does this mean it dries out skin only when 70 percent or dries out skin in general irregardless of 70 percent in general. One more thing it says is A layer of petrolatum applied to normal skin can reduce that loss by 50–75% for several hours. When they mean loss they mean water loss how many is several hours? https://en.wikipedia.org/wiki/Moisturizer — Preceding unsigned comment added by 110.151.108.88 (talk) 01:06, 22 January 2021 (UTC)


 * The cited source for the statement in our article is as ambiguous as the statement in our article, but the meaning is undoubtedly that the humectant draws water (mainly) from the air when the humidity is above 70%, resulting in a net moisturizing effect, but starts drawing the water from the dermis at humidities below 70%, resulting in a drying-out effect on the deeper skin layers. A relative humidity of 70% is high; most people live in less humid climes, and so the drying-out effect is more common. (The outermost skin layer should still remain more hydrated, though.) How long the occlusive effect of a coat of petrolatum lasts depends, among many factors, on how thick a layer has been slathered on and whether there are mechanical processes at play (like clothes rubbing the skin) that tend to remove the jelly. With a higher temperature, it becomes less viscous and is wiped off more easily, or may even just drip away. --Lambiam 11:01, 22 January 2021 (UTC)

Important natural resources
Is there any natural resource that's anywhere near as important as petroleum (oil) is? Coal, gold, and/or silver in the past, possibly, but what else? Land, water, salt, what else? Futurist110 (talk) 03:41, 22 January 2021 (UTC)
 * The bounty of the ocean. See Commercial fishing. 41.165.67.114 (talk) 06:29, 22 January 2021 (UTC)


 * One of the biggest is sand used in most construction projects. Graeme Bartlett (talk) 06:43, 22 January 2021 (UTC)


 * Wood? Clarityfiend (talk) 08:45, 22 January 2021 (UTC)


 * The atmosphere. ←Baseball Bugs What's up, Doc? carrots→ 10:22, 22 January 2021 (UTC)


 * Air and water. Or does the possibility to derive wealth from exploiting the natural resource determine its importance? Then, probably, arable land. --Lambiam 10:28, 22 January 2021 (UTC)


 * I find it is hard to spend money to enrich the shareholders of corporations if I don't have any air to breathe. So I would vote for air as being at least as economically important as anything else.  -- Jayron 32 16:05, 22 January 2021 (UTC)
 * Sunlight. Take the entire earth - lithosphere, hydrosphere, atmosphere, and biosphere - and place it in deep space far from any star, and it will cool to the point that life as we know it could not survive. --Khajidha (talk) 16:15, 22 January 2021 (UTC)