# Exactly how much of an iceberg is over water? **URL:** \ **Category:** Factual Questions\ **Created:** [August 7, 2008, 12:52pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152 "2008-08-07T12:52:45Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![muttrox](https://avatars.discourse-cdn.com/v4/letter/m/a8b319/32.png) [@muttrox](https://boards.straightdope.com/u/muttrox)\ **Post date:** [August 7, 2008, 12:52pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/1 "2008-08-07T12:52:45Z")
I’ve always heard “about one-tenth”. Is there a more accurate number? Or, to check my science - is it the ratio of the density of the iceberg compared to the water around it? [Wikipedia](http://en.wikipedia.org/wiki/Iceberg#Overview) says 920 vs 1025, about an 11% difference. Would that difference be theoretically equaly to the proportion of an iceberg that is out of the water? ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 7, 2008, 1:25pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/2 "2008-08-07T13:25:25Z")
I get 10.2%, but, yes. The same would be true of a quarter floating in mercury, or any solid with a density of less than the liquid it is in. ---
**Author:** ![Snarky\_Kong](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@Snarky\_Kong](https://boards.straightdope.com/u/Snarky_Kong)\ **Post date:** [August 7, 2008, 1:39pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/3 "2008-08-07T13:39:49Z")
How exact are we talking about? Temperature will affect the density of the water, and there will be other forces present other than weight and buoyancy. ---
**Author:** ![muttrox](https://avatars.discourse-cdn.com/v4/letter/m/a8b319/32.png) [@muttrox](https://boards.straightdope.com/u/muttrox)\ **Post date:** [August 7, 2008, 2:48pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/4 "2008-08-07T14:48:25Z")
This is exact enough for me, I wanted to confirm that the relationship of weight and buoyancy was what I thought. Thanks all! ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [August 7, 2008, 2:52pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/5 "2008-08-07T14:52:39Z")
Variations in density for Icebergs would include air bubbles, from microscopic, to rather large, which are non-uniform in distribution. The higher percentage above water might reflect that as well. Not sure how it was arrived at, though. Tris ---
**Author:** ![Mister\_Rik](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mister_rik/32/491_2.png) [@Mister\_Rik](https://boards.straightdope.com/u/Mister_Rik)\ **Post date:** [August 7, 2008, 6:55pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/6 "2008-08-07T18:55:36Z")
How about a [picture](http://www.mister-rik.com/hosted/iceberg.jpg)? ---
**Author:** ![Emerald\_Hawk](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Emerald\_Hawk](https://boards.straightdope.com/u/Emerald_Hawk)\ **Post date:** [August 7, 2008, 7:21pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/7 "2008-08-07T19:21:24Z")
[QUOTE=Mister Rik] How about a [picture](http://www.mister-rik.com/hosted/iceberg.jpg)? [/QUOTE] I’m pretty sure that’s a composite of two photos of different icebergs, but it’s still awesome looking. (On searching) Yup: > **[Giant Newfoundland Iceberg](https://www.snopes.com/fact-check/giant-newfoundland-iceberg/)** > > Rumor: A Newfoundland diver snapped an underwater photograph of an enormous iceberg. I still love it though, I hope I didn’t spoil the magic for anybody. ---
**Author:** ![Bytegeist](https://avatars.discourse-cdn.com/v4/letter/b/9dc877/32.png) [@Bytegeist](https://boards.straightdope.com/u/Bytegeist)\ **Post date:** [August 7, 2008, 7:37pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/8 "2008-08-07T19:37:13Z")
[QUOTE=Triskadecamus] Variations in density for Icebergs would include air bubbles, from microscopic, to rather large … [/QUOTE] So in fact, if the iceberg were _hollow_ — say the 'berg was basically a yard-thick shell of ice surrounding a building-sized volume of air — then that would throw the percentage totally off, wouldn’t it? More like 50% over water, not a puny 11. Bet you guys didn’t consider that. Well don’t say I didn’t warn you. ---
**Author:** ![muttrox](https://avatars.discourse-cdn.com/v4/letter/m/a8b319/32.png) [@muttrox](https://boards.straightdope.com/u/muttrox)\ **Post date:** [August 7, 2008, 7:55pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/9 "2008-08-07T19:55:02Z")
The OP assumed that the iceberg was made of the same substance as the water around it, frozen. There are also no black holes involved. ---
**Author:** ![The\_Flying\_Dutchman](https://avatars.discourse-cdn.com/v4/letter/t/9fc348/32.png) [@The\_Flying\_Dutchman](https://boards.straightdope.com/u/The_Flying_Dutchman)\ **Post date:** [August 7, 2008, 8:08pm UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/10 "2008-08-07T20:08:08Z")
[QUOTE=muttrox] The OP assumed that the iceberg was made of the same substance as the water around it, frozen. There are also no black holes involved. [/QUOTE] Actually, the iceberg is not exactly made of the same substance as the water around it. The iceburg is made up of fresh water which is significantly lighter than the water in the ocean, and if it drifts into the Gulf of St Lawrence say, it will likely sink a little more. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [August 8, 2008, 12:31am UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/11 "2008-08-08T00:31:01Z")
[QUOTE=Santo Rugger] I get 10.2%, but, yes. The same would be true of a quarter floating in mercury, or any solid with a density of less than the liquid it is in. [/QUOTE] Hm? I’m pretty sure that’s incorrect. If I have some styrofoam and set it on top of mercury, 89.8% of it isn’t going to sink under the surface, I’d be pretty sure. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [August 8, 2008, 12:55am UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/12 "2008-08-08T00:55:02Z")
I had to look twice at that statement as well, but in the end I decided that **Santo Rugger** was only saying that the same method of calculation would apply. I haven’t bothered to work through the math myself. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 8, 2008, 2:10am UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/13 "2008-08-08T02:10:12Z")
Sorry for not articulating what I meant, I worded it really poorly. Thanks for clearing that up, **WarmNPrickley**. But, **Sage Rat** , you got me curious, so here are the calcs for Styrofoam and mercury: Density of Styrofoam is 40kg / m[sup]3[/sup], while density of mercury is 13.534g / cm[sup]3[/sup], or 135 kg / m[sup]3[/sup], giving 30% sinking below the water. There’s a more detailed discussion and equations on Wiki: > **[Buoyancy](https://en.wikipedia.org/wiki/Bouyancy)** > > Buoyancy (/ˈbɔɪənsi, ˈbuːjənsi/), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in For... ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [August 8, 2008, 2:59am UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/14 "2008-08-08T02:59:15Z")
[QUOTE=Santo Rugger] Sorry for not articulating what I meant, I worded it really poorly. Thanks for clearing that up, **WarmNPrickley**. But, **Sage Rat** , you got me curious, so here are the calcs for Styrofoam and mercury: Density of Styrofoam is 40kg / m[sup]3[/sup], while density of mercury is 13.534g / cm[sup]3[/sup], or 135 kg / m[sup]3[/sup], giving 30% sinking below the water. There’s a more detailed discussion and equations on Wiki: > **[Buoyancy](https://en.wikipedia.org/wiki/Bouyancy)** > > Buoyancy (/ˈbɔɪənsi, ˈbuːjənsi/), or upthrust, is the force exerted by a fluid opposing the weight of a partially or fully immersed object (which may also be a parcel of fluid). In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus, the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The p For... [/QUOTE] You’re off by quite a bit. One cubic meter of fresh water weighs one metric ton (2,000kg) and I know considerably more that 30% of a foam cup is above the water when one floats on it. Lessee, 10cm is 1/100 of a meter so a cubic meter is 100x100x100 or 1,000,000cc Wiki confirms that Hg is 13.534g/cc so multiplying that by 1,000,000 gives 13,534,000 g or 13,534 kg / cubic meter, or 6.767 metric tons which sounds about right. 40 / 13534 = 0.00296 so about 0.3% of the cup would be submerged in a pool of mercury. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [August 8, 2008, 3:21am UTC](https://boards.straightdope.com/t/exactly-how-much-of-an-iceberg-is-over-water/459152/15 "2008-08-08T03:21:51Z")
[QUOTE=DesertDog] You’re off by quite a bit. One cubic meter of fresh water weighs one metric ton (2,000kg) and I know considerably more that 30% of a foam cup is above the water when one floats on it. Lessee, 10cm is 1/100 of a meter so a cubic meter is 100x100x100 or 1,000,000cc Wiki confirms that Hg is 13.534g/cc so multiplying that by 1,000,000 gives 13,534,000 g or 13,534 kg / cubic meter, or 6.767 metric tons which sounds about right. 40 / 13534 = 0.00296 so about 0.3% of the cup would be submerged in a pool of mercury. [/QUOTE] Strike the 6.767 metric tons. 1,000 kilos = a metric ton, not 2,000. :smack: