Why would the oceans overflow if the glaciers melt?

[BlancoNino]

My glass of ice-water won't overflow when the ice cubes melt. It will stay at the same level.

Discuss.

 

[DnetMHZ]

Do your ice cubes protrude significantly above the surface of the water?

 

[DrPizza]

You are correct, in regard to the ice at the North Pole.

However, the ice in Greenland and Antarctica are on top of the land, not floating in the water.

 

[conehead433]

Maybe it's because some glaciers are on land masses and not in the water. If you actually meant icebergs a good portion of some of them is above water as well.

 

[jcwagers]

Are you sure? Did you put the ice in and then fill the glass to the very top of the glass......to the point where it would overflow if you put anymore in there? Of course, glaciers melting would be on a much more massive scale than a glass of water with an ice cube or two.........

 

[BlancoNino]

Originally posted by: DnetMHZ
Do your ice cubes protrude significantly above the surface of the water?

Somewhat.

 

[BoomerD]

First of all, the oceans won't overflow, but their levels will rise dramatically.
Next...with your glass of ice water analogy, dump a large bag of ice into a container that drains ONLY into your glass and let that melt...I'm sure the additional melting water WILL cause your glass to overflow. Since the glaciers are NOT currently submerged in the ocean, adding all the water they contain will raise the water level in the oceans.

 

[Scatterplot]

The glaciers float the same way ice does... I don't think they would cause an overflow. The water doesn't gain or lose weight when it freezes, and therefore the water displaced by a floating glacier (or anything else) is equal to the weight of an equal volume of water, and since the glacier IS water, when it melts, it takes up the same amount of "water volume," the only difference being that it no longer sticks up out of the ground.

Unless there is some other reason that glaciers would flood- for example, if one was sitting on the ocean floor, then it would cause more water to enter.

 

[CraKaJaX]

If the ice bergs in the ocean melt, the water level will stay the same. If the glaciers and ice bergs on land melt... we'll have a problem. it's all dealing with the density of the ice and stuff.

 

[BlancoNino]

Originally posted by: jcwagers
Are you sure? Did you put the ice in and then fill the glass to the very top of the glass......to the point where it would overflow if you put anymore in there? Of course, glaciers melting would be on a much more massive scale than a glass of water with an ice cube or two.........

I don't know. My ice cubes are taking up about 20% of my glass. How much % of water do the ice-burgs and glaciers take up?

 

[DaTT]

Water expands when frozen.......

 

[jcwagers]

I don't know either. It just seemed strange when you said it didn't overflow. I can see from the other posts what they're saying though...so you're probably right about the whole thing.

 

[DrPizza]

Originally posted by: conehead433
Maybe it's because some glaciers are on land masses and not in the water. If you actually meant icebergs a good prtion of some of them is above water as well.

Regardless of the size of the iceberg, as long as it's not resting on the ocean floor, it will displace a volume of water with the same mass as its own mass. (Archimedes principal). However, if you really want to be picky, you can deal with the differences in density due to the salt content in the ocean, as well as the mixing of the relatively fresh water composing the bergs.

 

[BoomerD]

Originally posted by: Scatterplot
The glaciers float the same way ice does... I don't think they would cause an overflow. The water doesn't gain or lose weight when it freezes, and therefore the water displaced by a floating glacier (or anything else) is equal to the weight of an equal volume of water, and since the glacier IS water, when it melts, it takes up the same amount of "water volume," the only difference being that it no longer sticks up out of the ground.

Unless there is some other reason that glaciers would flood- for example, if one was sitting on the ocean floor, then it would cause more water to enter.

Sounds like you're confusing glaciers with icebergs. Glaciers are on land...when pieces of them break off and fall into the ocean, they become icebergs...

 

[everman]

Supposedly if enough fresh water ice melted into the ocean fast enough we could see a major disturbance in ocean currents (movement of warm and cool ocean water), causing major weather disturbances leading to another ice age. Global warming would cause a big freeze.

 

[CraKaJaX]

OP, have you taken physics?

 

[BlancoNino]

Originally posted by: CraKaJaX
OP, have you taken physics?

No, but I did stay at a Holiday Inn Express last night.

 

[RGUN]

Everyone saying ice in the glass melting = overflow should stop and think before they talk. The ice, which is made out of water is displacing its weight in water... guess what that means???? once it melts, the water level DOES NOT change... it just fills the pocket that it was once displacing

 

[DaTT]

Originally posted by: RGUN
Everyone saying ice in the glass melting = overflow should stop and think before they talk. The ice, which is made out of water is displacing its weight in water... guess what that means???? once it melts, the water level DOES NOT change... it just fills the pocket that it was once displacing

Would water level not drop slightly?

 

[EKKC]

OMG WE'RE ALL GONNNNNNNA DIEE!!!!

watched Day After Tomorrow too many times?

 

[FoBoT]

water expands when it freezes

so it likely contracts when ice melts back to a liquid state

 

[randay]

1. Drop 10 ice cubes into a full glass of water.
2. slap yourself up side the head.
3. say "oooooohhhh, now I get it!".

 

[feelingshorter]

Originally posted by: DaTT

Originally posted by: RGUN
Everyone saying ice in the glass melting = overflow should stop and think before they talk. The ice, which is made out of water is displacing its weight in water... guess what that means???? once it melts, the water level DOES NOT change... it just fills the pocket that it was once displacing

Would water level not drop slightly?

based on what he said, no. Its the ice on land that we have to worry about. When those ice melt, it will cause the world's ocean level to rise somewhat.

 

[DrPizza]

Hmmmm... on second thought...

Melting icebergs *will* raise the level of the ocean. Icebergs are fresh water with a lower density than salt water.
I'll demonstrate with approximate numbers:

Lets assume a 1000gram chunk of ice floating in fresh water with a density of 1.000 g/cm3. When it melts, it will take up 1000cm3, but since ice expands when it freezes, it has a volume of roughly 1100 cm3 (correct me if you wish, I'm not looking up the exact density of ice)
It will displace 1000 cm3 of water, which is less than it's own volume. Thus, about 10% would be above the water.

Now, that 1000 gram chunk of ice floating in salt water with a density of 1.1g/cm3 will still displace 1000 grams of the icewater. However, this is less than 1000cm3 of the water. Actually, 909 cm3 are displaced (assuming the 1.1 g/cm3 density, which I'm just taking a wild guess at; I'm sure it's lower, but it's still more than that of freshwater). So, when that 1000grams of ice melts, it will fill in the 909cm3 "depression" in the water, and have 91 cm3 left over. But, it's quite that simple. The freshwater isn't going to stay separate. It will, of course, slowly mix with the salt water, lowering the concentration of salt and the density of the water. Regardless, that water would have a lower density, same mass, and therefore, higher volume.


edit: regardless, the effect of the melting icebergs/polar ice at the North Pole is insignificant compared to melting glaciers, greenland, antarctica, etc.

 

[DaTT]

Originally posted by: BlancoNino

Originally posted by: CraKaJaX
OP, have you taken physics?

No, but I did stay at a Holiday Inn Express last night.

But did your save tons of money by switching to Geico.