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Scifi and Fantasy Forum: Speculation: What if Ice was heavier than Water ? :
Archive through Mar 09, 2004
Archive through Mar 09, 2004
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As you know, Ice is lighter than Water. Drop an icecube in a glass of water, and it will float. Water is probably the only known liquid which becomes less dense when it freezes solid. (ok, maybe there are a few others, I'm no great expert. but I'm sure none of them are as readily available as good old H2O).
So, what I want to know: how do you think Earth would have been different if ice was heavier than water (except for the obvios fact that ice-cubes would sink to the bottom of your Coke glass) ?
Posted By:  Nomad Jun 03, 2003 - 10:37 am |       | The water would be colder all the time cause the sun would not be able to melt as much below the surface at a certain depth. therefore..the earth would be a colde climated planet.
| Posted By: Aslan Jun 03, 2003 - 04:44 pm | | We probably wouldn't have an icecap on the north pole. Water begins to get less dense at 4 degrees (Celsius, I think). If, instead of this scenario, water continued to become more dense as it approached freezing, the coldest water at the top would sink below the surface, to the bottom of the ocean. It would mix with the warmer water, moderating its temperature and forcing warmer water upward. In other words, the water would do a slow boil. Thus, unless the whole regional body of water froze, top to bottom, you'd never see ice. I find this unlikely in the case of an ocean, but possible for ponds and lakes. These smaller bodies of water would freeze later in the year (due to the slow boil) and, as Nomad postulated, the bottoms may never unfreeze (depending on depth). Thus lakes and ponds would have a steep temperature gradient from top to bottom. It could be 60 or 65 degrees near the surface and frozen a few dozen meters below. In the winter, lakes and ponds would freeze entirely. That means that the fish that currently survive and swim around below the surface would either not exist or have some sort of physical adaptation that allows them to survive a deep freeze (certainly possible, and I'm sure there are some Earth organisms that do this). Regardless, ice fishing would be out of the question...
I don't think it would affect our weather types very much. The top of the troposphere is very cold, which is why thunderclouds are made of ice at the top layers. The ice is held aloft by strong upward air currents. A miniscule change in ice weight with respect to water probably wouldn't affect the way clouds of any type operate. The tops of clouds will always be icy because it's colder, not because of weight.
If ice were REALLY heavy, then we probably wouldn't have thunderstorms or cirrus clouds. Assuming that ice particles would be too heavy for the air currents to support. Cloud tops would be limited, eliminating thunderstorms and mountain precipitation. Mountains would be deserts above a certain height.
That's all I can come up with off the top of my head. Wouldn't change hockey much, I don't think.
| Posted By: Ding_man Jun 04, 2003 - 06:12 am | | Wow very interesting
| Posted By: Nomad Jun 04, 2003 - 09:23 am | | Hockey! LoL
| Posted By: Iznardi Jun 04, 2003 - 12:26 pm | | Yeah, but the Titanic would still be afloat.
Well one day you teacher might ask you these questions :
Is water heavier when it is frozen? False, it is not heavier when it is frozen. It is actually lighter.
Is water more dense when it is frozen? No water is less dense when it is frozen.
| Posted By: Adam Jan 06, 2004 - 10:55 pm | | Ice is not lighter than water. It is less dense. Very different.
| Posted By: Aslan Jan 07, 2004 - 12:17 pm | | Weight is a measure of earthward force, which equals acceleration (via gravity) * mass.
Let's assume gravity is a constant. So, for weight to differ, mass of samples must differ.
Density, as we've said, decreases as water changes to ice.
Density = mass / volume.
So if density decreases, volume increases.
That means that a 1kg mass of ice would be larger than a 1kg mass of water.
If you want to compare equal volumes of ice and water, a liter of ice would have less mass than a liter of water (density and mass are directly proportional).
Therefore, water has less mass than ice at equal volumes. Assuming that gravity is constant, water would weigh more.
Or, mathematically:
weight = gravity * mass mass = density * volume
weight = gravity * density * volume
if gravity and volume are held constant, then weight is directly dependent on density.
Less density = less weight.
Thus, with equal and any gravity, ice is lighter than water.
Did I miss anything?
| Posted By: Adam Jan 07, 2004 - 08:03 pm | | You're confusing yourself with the density part. Forget about density. No matter what the density is, teh mass does not change. The same amount of any given matter will always have the same mass, regardless of density.
It is ALWAYS F=ma, where:
F = Force
m = mass
a = acceleration
Density is mass/volume. Density is what makes ice float in water. It has less density than water, or less Specific Gravity if you wish to use that term.
Regardless of the state of the material, its mass is not changing.
"Therefore, water has less mass than ice at equal volumes. Assuming that gravity is constant, water would weigh more."
But that means subtracting some of the mass and then comparing inequal masses. 1kg of ice weighs the same as 1kg of water.
"Or, mathematically:
weight = gravity * mass mass = density * volume
weight = gravity * density * volume"
Weight = F, where F=ma. Still reliant upon mass and acceleration.
Mass is an independent variable. It remains the same regardless of the gravity, regardless of acceleration, regardless of density. A ton of water in liquid form has exactly the same mass as a ton of water in gaseous form.
| Posted By: Aslan Jan 08, 2004 - 05:22 am | |
Quote:The same amount of any given matter will always have the same mass, regardless of density.
What you're saying is true. Where we differ is our definition of "same amount". What I'm saying is that a liter of water is heavier than a liter of ice. Which is true. What you're saying is that a kg of water weighs the same as a kg of ice. Which is also true.
But you could also say that a kg of feathers weighs the same as a kg of water. But I would say that water is heavier than feathers. Do you understand where I'm coming from, now? If you're using mass as your "same amount", then nothing is heavier than anything else.
| Posted By: Adam Jan 08, 2004 - 05:33 am | | Yes, litre is a volume measure, not mass. Any given volume of a less dense material is lighter than that volume of a more dense material. But any given amount of water is exactly the same weight if it is frozen or turned to steam.
| Posted By: Aslan Jan 08, 2004 - 12:39 pm | | no argument from here!
For arguements sake, let us assume that for whatever reason, ice did not float. Would this sinking ice not displace much more water than it currently does, thus causing the oceans and other bodies of water to rise above much of the existing landmasses that now stand above sea level?
| Posted By: Athalia Mar 03, 2004 - 03:13 pm | | How cold is the deep ocean floor? below freezing i think. So, the water level would stay the same because everything on the bottom would freeze enough so that the actual level didn't rise...this makes no sense, ignore it.
| Posted By: Aldan Mar 03, 2004 - 03:41 pm | | Ignore what? What are you talking about?
*Aldan smirks*
The deepest portions of the ocean are NOT frozen. In fact, while the water's cold, it is only (if I remember correctly) down in the mid-40s farenheit, rather than below 33 degrees farenheit.
As for your question, the ocean would end up freezing into its depths at about the same place that the polar ice cap is (it wouldn't expand much past it). Therefore, instead of a cap, we'd just have a block of ice at our North Pole, stretching from floor to above water. It would continue to grow as the years went on, creating a small ice continent/island.
The water levels would have stabilized long ago, so our land continents would be smaller, but there'd still be plenty of land left for people to live on.
| Posted By: Athalia Mar 05, 2004 - 03:28 pm | | *ath knows the bottom of the ocean is not frozen, but if ice sank wouldn't the bottom freeze?
| Posted By: Aldan Mar 05, 2004 - 03:58 pm | | Or would it melt??
If, as we are hypothesizing, ice were to sink, it would have to be more dense and therefore the same volume would weigh more. The same mass would have a smaller volume once frozen. As frozen ice landed on the ocean bottom it would stay frozen (ignoring hydrothermal vents etc.). The reason is that water only sinks in two locations in the ocean (either side of Greenland and the Weddell Sea - Antarctica). At these locations water is less than 0oC but unfrozen due to its high salt content.
Early in Earth's history there is some evidence that the entire planet was covered in ice (snowball Earth theory). Ice reflects solar radiation (high albedo) and therefore the runaway refrigerator Earth is a positive feedback loop.
In our "sinking ice" hypothesis it would be much easier to generate a snowball Earth. The reason is that as the ice piles up and develops over the oceans near the poles the planet would cool. Warmest waters would become more and more salty (as ice formed from the bottom of the ocean up) so the Earth's ocean's may never freeze completely but the top layer might be awfully thin. Lastly, water would continue to evaporate and fall as rain, but, as the planet cools rain turns to snow, glaciers grow and eventually, , snowball Earth!
Last, lastly, if the oceans froze (and it sinks) then sea level will be lower (same mass, less volume). Incidentally, life is pretty improbable in the sinking ice World.
Earthstronaut
What if beer had never been invented...
Aaaaaaaaaarrrrgghhhh!
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