# A swimming pool on the Moon. **URL:** \ **Category:** Factual Questions\ **Created:** [August 2, 2009, 7:28pm UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085 "2009-08-02T19:28:16Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [August 2, 2009, 7:28pm UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/1 "2009-08-02T19:28:16Z")
If you wanted a swimming pool on the moon (indoors), what would you need to change to make it work for the low gravity? Higher walls, gel the water? Could you have a jacuzzi at all? Or is 1/6 g high enough to have water behave? Would a cannonball dive empty the whole thing? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 2, 2009, 10:54pm UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/2 "2009-08-02T22:54:46Z")
What do you mean, make water behave? It’s water; it just sits there. As long as you have any gravity at all, it’ll pool in the, er, pool. You could make bigger splashes by playing in the water, but a cannonball will have about the same effect as on Earth, assuming you’re jumping from the same height, since it’ll take less energy to make any given amount of splash, but you’ll also have less energy when you hit the water. ---
**Author:** ![thirdname](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@thirdname](https://boards.straightdope.com/u/thirdname)\ **Post date:** [August 2, 2009, 11:01pm UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/3 "2009-08-02T23:01:44Z")
It’ll work fine as long as those pesky Russians don’t nuke it. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [August 2, 2009, 11:05pm UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/4 "2009-08-02T23:05:10Z")
Your biggest risk is that if you dive deep, your body won’t have as much buoyancy, so you have a higher risk of drowning before you reach the surface. ---
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [August 2, 2009, 11:07pm UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/5 "2009-08-02T23:07:37Z")
> [@Chronos](#): > > … but you’ll also have less energy when you hit the water. Hadn’t thought of that. Anyway, I am sure that water will eventually pool in the pool but as you said, you can splash more with less effort. I just don’t know how much more you can splash with how less effort. Would a traditional pool with the water just inches below the rim hold the water in with people playing in it? Could you have chairs around the pool that won’t be wet all the time? Remember that traditional pools have a lip around the edge that prevents the water that splashes out from returning to the pool (for hygiene reasons, I presume). Would a pool on the moon empty with a couple of kids splashing around? ---
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [August 2, 2009, 11:11pm UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/6 "2009-08-02T23:11:07Z")
> [@thirdname](#): > > It’ll work fine as long as those pesky Russians don’t nuke it. Exactly. Had the day home alone reading Sci-Fi. > [@Bryan\_Ekers](#): > > Your biggest risk is that if you dive deep, your body won’t have as much buoyancy, so you have a higher risk of drowning before you reach the surface. An interesting concern. A presume that 1/6 g is enough that you cannot drown in a blob of water as you could in zero g. Is that even true? That a big blob of water in zero g could wrap itself around your head and drown you? ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [August 3, 2009, 12:41am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/7 "2009-08-03T00:41:21Z")
No sweat. When you push off from the bottom of the pool you’ll go 5/6ths farther than you would on Earth, right? That’ll have you up and out of the water in jig time. ---
**Author:** ![athelas](https://avatars.discourse-cdn.com/v4/letter/a/5e9695/32.png) [@athelas](https://boards.straightdope.com/u/athelas)\ **Post date:** [August 3, 2009, 12:57am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/8 "2009-08-03T00:57:46Z")
Since the moon has no atmospheric humidity and is subject to extremes of temperature, wouldn’t the water freeze, boil, or sublime? ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [August 3, 2009, 1:02am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/9 "2009-08-03T01:02:13Z")
It’s going to freeze and boil and, once there is no liquid, keep subliming. The solar cycle is 28 days so temperatures can go pretty far up and down. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [August 3, 2009, 1:05am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/10 "2009-08-03T01:05:12Z")
OP specified ‘indoors’. ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [August 3, 2009, 1:06am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/11 "2009-08-03T01:06:13Z")
> [@athelas](#): > > Since the moon has no atmospheric humidity and is subject to extremes of temperature, wouldn’t the water freeze, boil, or sublime? The OP did say indoors. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 3, 2009, 1:59am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/12 "2009-08-03T01:59:00Z")
> [@](#): > > Would a traditional pool with the water just inches below the rim hold the water in with people playing in it? Of course not: The few inches of rim isn’t even enough to hold the splashes in on Earth. Why is this a problem? But if you want to have the same amount of splash containment (such as it is) as in an Earthly pool, just take whatever distance from water to rim you consider acceptable here, and multiply by 6. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [August 3, 2009, 2:03am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/13 "2009-08-03T02:03:47Z")
> [@Sapo](#): > > Hadn’t thought of that. > > Anyway, I am sure that water will eventually pool in the pool but as you said, you can splash more with less effort. I just don’t know how much more you can splash with how less effort. Would a traditional pool with the water just inches below the rim hold the water in with people playing in it? Could you have chairs around the pool that won’t be wet all the time? > > Remember that traditional pools have a lip around the edge that prevents the water that splashes out from returning to the pool (for hygiene reasons, I presume). Would a pool on the moon empty with a couple of kids splashing around? I’m not sure that’s why there is a drain around the lip. I think it has more to do with preventing sloshing back and forth. If the edges of the pool were just curved upwards, waves creates would slosh one way, then the other. With the right action, you could set up reinforcements to the wave and cause some major overflows. With the grates along the edges, the sloshed water is poured away and the energy dissipated. I’m guessing that water is returned to the pool - otherwise, the pool would have to constantly be repleneshed with new water. That seems like quite a waste. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [August 3, 2009, 2:13am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/14 "2009-08-03T02:13:04Z")
_Giant waves are what you make Swimming on the Moon I hope my legs don’t break Swimming on the Moon We could swim forever Swimming on the Moon We could drown together Swimming on, swimming on the Moon_ ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [August 3, 2009, 2:53am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/15 "2009-08-03T02:53:14Z")
Am I the only one who thought this was a line item on the stimulus bill? ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [August 3, 2009, 2:54am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/16 "2009-08-03T02:54:34Z")
> [@Bryan\_Ekers](#): > > Your biggest risk is that if you dive deep, your body won’t have as much buoyancy, so you have a higher risk of drowning before you reach the surface. Are you sure? Objects float when they displace their own weight in water. Onthe moon you weigh 1/6th as much, but so does water. Doesn’t this mean you’d have exactly the same buoyancy? ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [August 3, 2009, 3:11am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/17 "2009-08-03T03:11:40Z")
> [@Johnny\_L.A](#): > > _Giant waves are what you make > Swimming on the Moon > I hope my legs don’t break > Swimming on the Moon > We could swim forever > Swimming on the Moon > We could drown together > Swimming on, swimming on the Moon_ > [@](#): > > \*Swimming on the moon > Where talk is cheap and vision true > Swimming on the moon > But I would rather be with you > Somewhere in San Francisco > On a back porch in July > Just looking up to heaven > At this crescent in the sky > > Swimming on the moon > With nothing left to do > A lovely view of heaven > But I’d rather be with you.\* 😉 ---
**Author:** ![Captain\_Carrot](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@Captain\_Carrot](https://boards.straightdope.com/u/Captain_Carrot)\ **Post date:** [August 3, 2009, 3:26am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/18 "2009-08-03T03:26:20Z")
> [@Sapo](#): > > A presume that 1/6 g is enough that you cannot drown in a blob of water as you could in zero g. Is that even true? That a big blob of water in zero g could wrap itself around your head and drown you? That seems ridiculous to me, but IANAPhysicist. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [August 3, 2009, 3:27am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/19 "2009-08-03T03:27:22Z")
I don’t know… Some people are pretty dense. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 3, 2009, 6:23am UTC](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085/20 "2009-08-03T06:23:30Z")
> [@](#): > > Are you sure? Objects float when they displace their own weight in water. Onthe moon you weigh 1/6th as much, but so does water. Doesn’t this mean you’d have exactly the same buoyancy? Whether you float or not will be unchanged, but your buoyant force (like your weight) will be 1/6 of what it is on Earth. If you’re just backstroking on the surface, this isn’t a problem, but if you were to find yourself on the bottom of the pool for some reason, it’d take you longer to float back to the surface. I doubt it would be long enough to make drowning a serious hazard, for a pool of any reasonable depth, but the calculations are pretty messy, so I don’t feel like actually working it out right now. [Next page](https://boards.straightdope.com/t/a-swimming-pool-on-the-moon/505085.md?page=2)