Physics anyone? Fluid mechanics stuff...

[silkiechick05]

Okay let's see if anyone can help me...


There is an ice cube with iron in the middle of it.

The ice cube is placed into a cup with water.

When the ice cube melts, will the water level be:

The same

Lower

Or Higher

Than the original level

 

[Iowa Roo Mom]

Quote:
As in... the same as before the cube was placed in it, or before the cube began to melt?

 

[ThePamperedPullet]

In fluid dynamics, water is the only liquid that expands when frozen. The iron only displaces the area in which it exists. Therefore when the ice cube melts the water level will actually be less.

 

[WalkingWolf]

Water level will be lower, the iron displaces the same whether sitting in the cube or sitting on the bottom. When water goes from a liquid state to a solid it expands, once it melts it will be less volume than it was as a solid, thus reducing the total volume of the liquid.

 

[WalkingWolf]

Quote:
LOL, pampered you beat me by 1 minute. It was a trick question I guess as the iron was completely not relevant to the equation.

 

[rebelcowboysnb]

Assuming the block of iron weighed enough to sink the ice cube right off the bat an there was no heat input from the room the water level would stay the same as it melted. The ice would melt an expand at the same rate as the water cooled an contracted.





If the Ice cube floated and or there was heat input from the room (which there would be) then the water level would go up as the cube melted.
If it floats then as it melts it will add water(mass) to the glass. Or if there is heat input from the room the ice would still melt an expand at the same rate but the water would cool an contract slower an less resulting in the same amount of mass but higher volume.






Ah forget that..... Forgot about that ice water bearer sudden expansion stuff. To get a true answer you would need the mass an temp of each part at the start of the scenario an the temp at the end. But with the info we have you could assume it would be slightly lower.

 

[ThePamperedPullet]

Quote:
LOL, pampered you beat me by 1 minute. It was a trick question I guess as the iron was completely not relevant to the equation.

Hey WalkingWolf
I had to go back and check because I thought you had beat me to it. I had to think a minute because that was a lot of years ago learning this stuff but I did remember this as one of our typical questions.

 

[seismic wonder2]

Iron contracts when chilled and expands when warmed. Ice sort of does the opposite.
If you play with the ratio of iron to ice, you could actually make the water level remain the same once all the temperatures have stablized.

But with the question as it is there is no way to tell what will happen. Need more input to properly answer.
But you could write it as an equation.....

 

[WalkingWolf]

Quote:
For the iron to expand with any effect on the level of water it would have to be at a temperature high enough to boil off the water. Most water unless filtered contains iron. When the ice test has been done in classrooms it rarely is filtered water. Iron takes high temperatures to expand, at extreme cold temperatures it becomes brittle. Ice floats to the top of water because when it goes from a fluid to a solid it retains the same weight with more volume, so it displaces the water making it rise, as it melts it returns to a normal state lowering the water level, more ice lower level. The iron would only have consequence if the ice contained air, such as the ice at the arctic. Arctic is mostly compacted snow. In the case of ice with air depending on the size of the iron and the content of the air it would displace more water, and make upon totally thawed even lower level.