Homework Help: Water level

1. Jun 3, 2007

eyehategod

if all the ice sticking out of the water from only the icebergs were to melt, would the water level go up or down?

2. Jun 3, 2007

prasannapakkiam

It should stay the same shouldn't it? Aww, I see; I never thought about it like that. Global Warming --> Ice Bergs melting --> Day after Tomorrow....

Hmm.

3. Jun 3, 2007

chemisttree

The level would stay the same. The ice is displacing its weight in water already.

4. Jun 3, 2007

ice109

im not sure if 1gram of ice melted equals 1cc of water though

edit

in fact i know 1 gram of ice displaces more than 1cc of water.

i think it would depend on the shape of iceburg and how much was above the water

5. Jun 3, 2007

prasannapakkiam

Ah I think:
But Icebergs are pure water, while seawater is salt water - a different density. Thus the volume rises by: 21.7%, thus the level rises by: 2.789%

6. Jun 3, 2007

prasannapakkiam

I think ice109 is wrong???? If pure ice melts in pure water.

x=mass of ice
Initially, the weight of volume displaced is equal to the weight of the ice...
Vi = F/(pg) = mg/pg = m/p = x
Finally, the volume displaced is equal to the volume of the ice...
Vf = volume of the water/ice thing = m/p = x

7. Jun 3, 2007

ice109

i have no idea what you're talking about but ice is less dense than water but mass is conserved so 1 gram of ice will yield 1 gram of water, so 1 gram of ice displaces more than 1 gram of water

8. Jun 3, 2007

prasannapakkiam

Principle of Flotation: The weight of the amount of fluid displaced by a floating object is equal to the weight of the object.

When not floating the volume displaced is equal to the object's volume. I think this is elementary physics. Until you can prove me wrong, I stand by my argument.

9. Jun 3, 2007

prasannapakkiam

The density of ice plays no role in this

10. Jun 3, 2007

damgo

Pranna's right; 1 gram of ice occupies more volume than 1 gram of water, but displaces exactly 1 cc (as much as 1 gram of water does.) The extra volume is what floats above the surface when it's ice. The shape is irrelevant, as is the exact density of the ice.

However, the melting of ice sheets sitting on land (not floating) would obviously raise the water level. So would thermal expansion of the water from whatever was causing the melting.

11. Jun 3, 2007

ice109

yea im dumb

12. Jun 4, 2007

prasannapakkiam

So what is all the chaos about Global Warming about? Okay Greenshouse Effect --> Melting of ice caps. According to me is ice=pure water and sea water =salt water, then the level only rises by a very small amount!

13. Jun 4, 2007

Integral

Staff Emeritus
The ice covering Greenland and Antartica is not floating. This is the extra water entering the system.

14. Jun 4, 2007

damgo

^^^ And there's also the thermal expansion of the oceans: warmer water is less dense and so occupies more volume. My understanding is that these two effects are roughly equally important in terms of sea level rise from global warming.

15. Jun 4, 2007

chemisttree

No way. One gram of ice melts to form one gram of water. That is the DEFINITION of 1 mL.

16. Jun 4, 2007

chemisttree

Not exactly, the ice covering the landmass of Greenland and the landmass of Antartica is not floating. All of the other ice that is covering the water is floating.

17. Jun 4, 2007

ice109

i meant that 1 gram of ice displaces more than 1 gram water as in 1 gram of ice has a bigger volume than one gram of water. i misused displaces