Blitz Posted June 10, 2016 Share Posted June 10, 2016 Will ice made by D2O would float on H2O liquid. Why , why not Link to comment Share on other sites More sharing options...
Strange Posted June 10, 2016 Share Posted June 10, 2016 The density of D2O is 1017.5 kg m-3 @ 3.82 °C The notional density of water is 1000 kg m-3 (at 20 °C, I think). So the heavy-water ice would (just about) sink. You might be able to find a temperature at which it would float (before it melted). Link to comment Share on other sites More sharing options...
John Cuthber Posted June 10, 2016 Share Posted June 10, 2016 It would dissolve. Link to comment Share on other sites More sharing options...
Blitz Posted June 11, 2016 Author Share Posted June 11, 2016 Strange, if that is the case, then as we know ice density is different from that of liquid. That should be applied to ice made by D2O. So the density would varie. The question is by how much, enough to sink it !!? Link to comment Share on other sites More sharing options...
StringJunky Posted June 11, 2016 Share Posted June 11, 2016 (edited) http://mathscinotes.com/2014/02/heavy-water-ice-cubes-do-not-float/ Density of H2O ice: 0.92g/cm3 Density of H2O liquid: 1.00g/cm3 Density of D2O ice: 1.02g/cm3 Edited June 11, 2016 by StringJunky Link to comment Share on other sites More sharing options...
Strange Posted June 11, 2016 Share Posted June 11, 2016 Strange, if that is the case, then as we know ice density is different from that of liquid. That should be applied to ice made by D2O. So the density would varie. The question is by how much, enough to sink it !!? Sorry. Forgot to include the source of my data. This should answer: http://www1.lsbu.ac.uk/water/water_properties.html It would dissolve. So would normal water ice. That doesn't stop icebergs being a hazard to shipping! Link to comment Share on other sites More sharing options...
John Cuthber Posted June 11, 2016 Share Posted June 11, 2016 So would normal water ice. That doesn't stop icebergs being a hazard to shipping! If the ice and the water are both at 0C then no, ordinary ice will not dissolve. There's a stable equilibrium. However , if you put heavy ice and ordinary water in an insulated container- a vacuum flask or some such- there is no temperature at which the heavy ice won't dissolve but the water is liquid. Link to comment Share on other sites More sharing options...
StringJunky Posted June 11, 2016 Share Posted June 11, 2016 If the ice and the water are both at 0C then no, ordinary ice will not dissolve. There's a stable equilibrium. However , if you put heavy ice and ordinary water in an insulated container- a vacuum flask or some such- there is no temperature at which the heavy ice won't dissolve but the water is liquid. If heavy water ice starts at 3.81oC and it is in ordinary water at a temp of 0oC why does the heavy ice dissolve but ordinary ice won't? Link to comment Share on other sites More sharing options...
Strange Posted June 11, 2016 Share Posted June 11, 2016 If the ice and the water are both at 0C then no, ordinary ice will not dissolve. There's a stable equilibrium. Icebergs are a danger to shipping in water above 0C. However , if you put heavy ice and ordinary water in an insulated container- a vacuum flask or some such- there is no temperature at which the heavy ice won't dissolve but the water is liquid. How about 3 C. Link to comment Share on other sites More sharing options...
John Cuthber Posted June 12, 2016 Share Posted June 12, 2016 Icebergs are a danger to shipping in water above 0C. How about 3 C. Icebergs are are a danger to shipping while they are melting. So what? At 3 degrees the heavy ice will dissolve. If heavy water ice starts at 3.81oC and it is in ordinary water at a temp of 0oC why does the heavy ice dissolve but ordinary ice won't? If I put some wax (which melts at 50C) in some boiling water at 100 C what will happen? If I put some heavy ice (which melts at 3.81C) in some water at at 0C what will happen? The difference is that the molten wax won't mix with the water. Link to comment Share on other sites More sharing options...
Strange Posted June 12, 2016 Share Posted June 12, 2016 Icebergs are are a danger to shipping while they are melting. So what? So, ice can exist in water that is warmer than zero. Your statements seemed to imply that asking about whether it would float or sink were meaningless. If I put some wax (which melts at 50C) in some boiling water at 100 C what will happen? If I put some heavy ice (which melts at 3.81C) in some water at at 0C what will happen? You are comparing two different things: something in water above its melting point and something in water below its melting point. Surely, what you mean is: If I put some wax (which melts at 50C) in some water at 46.19 C what will happen? If I put some heavy ice (which melts at 3.81C) in some water at at 0C what will happen? In both cases, it will float. Link to comment Share on other sites More sharing options...
John Cuthber Posted June 12, 2016 Share Posted June 12, 2016 So, ice can exist in water that is warmer than zero. Your statements seemed to imply that asking about whether it would float or sink were meaningless. You are comparing two different things: something in water above its melting point and something in water below its melting point. Surely, what you mean is: If I put some wax (which melts at 50C) in some water at 46.19 C what will happen? If I put some heavy ice (which melts at 3.81C) in some water at at 0C what will happen? In both cases, it will float. If I pick the right wax, in both cases it will not float. (See String junky's vid) But, in the long run, the heavy ice will dissolve. Your statement is meaningful- but wrong. Does that make it better or worse than mine? Link to comment Share on other sites More sharing options...
Strange Posted June 12, 2016 Share Posted June 12, 2016 If we are being that picky, then the wax may dissolve as well (if chosen appropriately). However, you have ignored the fact that the melting point of heavy ice is above the freezing point of (normal) water and so, as far as I can see, it is quite possible for heavy ice to remain indefinitely in liquid water. Link to comment Share on other sites More sharing options...
StringJunky Posted June 12, 2016 Share Posted June 12, 2016 If we are being that picky, then the wax may dissolve as well (if chosen appropriately). However, you have ignored the fact that the melting point of heavy ice is above the freezing point of (normal) water and so, as far as I can see, it is quite possible for heavy ice to remain indefinitely in liquid water. Tht's what I thought: anythiing below 3.8 will keep it frozen Link to comment Share on other sites More sharing options...
John Cuthber Posted June 12, 2016 Share Posted June 12, 2016 If we are being that picky, then the wax may dissolve as well (if chosen appropriately). However, you have ignored the fact that the melting point of heavy ice is above the freezing point of (normal) water and so, as far as I can see, it is quite possible for heavy ice to remain indefinitely in liquid water. The melting point of salt is about 800 degrees above that of water. By your logic, salt won't dissolve in water. Would you like to try again? Link to comment Share on other sites More sharing options...
Strange Posted June 12, 2016 Share Posted June 12, 2016 The melting point of salt is about 800 degrees above that of water. By your logic, salt won't dissolve in water. Would you like to try again? Ah, I see what you mean. Good point, well made. Link to comment Share on other sites More sharing options...
John Cuthber Posted June 12, 2016 Share Posted June 12, 2016 Ah, I see what you mean. Good point, well made. I thought I'd made it quite well enough, back in post 3. Link to comment Share on other sites More sharing options...
Strange Posted June 12, 2016 Share Posted June 12, 2016 I thought I'd made it quite well enough, back in post 3. But if several people clearly don't understand, maybe you need to clarify rather than simply repeating the same thing. Link to comment Share on other sites More sharing options...
John Cuthber Posted June 12, 2016 Share Posted June 12, 2016 But if several people clearly don't understand, maybe you need to clarify rather than simply repeating the same thing. Sorry, I assumed that you knew that salt would dissolve in water and that the heavy ice (which you saw sink in that video) would sink. Sometimes it's difficult to know what level to pitch an explanation. Link to comment Share on other sites More sharing options...
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