Lockjaw Posted June 20, 2010 Share Posted June 20, 2010 The original question doesn't make a lot of sense. Yes it does. The language used, plus the reasoning regarding the alleged weightlessness of gases, is scientifically incorrect but we all knew exactly what she meant and how to correct her misconceptions. I put it to you, therefore, that it made perfect sense. Link to comment Share on other sites More sharing options...
Guest sibon Posted June 20, 2010 Share Posted June 20, 2010 Yes it does. The language used, plus the reasoning regarding the alleged weightlessness of gases, is scientifically incorrect but we all knew exactly what she meant and how to correct her misconceptions. I put it to you, therefore, that it made perfect sense. I disagree. It needs more definition. For a start, the question doesn't refer to gases, it merely says "Why is water heavy?". That question has so many possible answers that it is pretty meaningless. Even if I did know what she meant really:) Link to comment Share on other sites More sharing options...
JFKvsNixon Posted June 20, 2010 Share Posted June 20, 2010 Thank you Mr Strix If water is made up of hydrogen, which is a gas... and oxygen, which is a gas... ... why doesn't it weigh nothing at all? 1 litre of water weighs 1 KG. Link to comment Share on other sites More sharing options...
max Posted June 20, 2010 Share Posted June 20, 2010 Surely it's gravity that makes water heavy so let's not confuse things with all this molecular density stuff. Link to comment Share on other sites More sharing options...
Grandad.Malky Posted June 20, 2010 Share Posted June 20, 2010 You learn something new every day, except the 1 ltr = 1 kg I already knew that, well I did learn something. Link to comment Share on other sites More sharing options...
Strix Posted June 20, 2010 Author Share Posted June 20, 2010 Surely it's gravity that makes water heavy so let's not confuse things with all this molecular density stuff. Quite right gravity can pass between the molecules of a gas, but there's less room for it to get between liquid molecules, so they get pinned to the floor more Loving the Douglas Adams science of this thread Link to comment Share on other sites More sharing options...
Grandad.Malky Posted June 20, 2010 Share Posted June 20, 2010 Molecules are more densely packed in a liquid than in a gas so it weighs more ………….. right got that , if the molecules become even more densely packed they will form a solid which following the logic would be heavier still so how come ice floats. Link to comment Share on other sites More sharing options...
JFKvsNixon Posted June 20, 2010 Share Posted June 20, 2010 Molecules are more densely packed in a liquid than in a gas so it weighs more ………….. right got that , if the molecules become even more densely packed they will form a solid which following the logic would be heavier still so how come ice floats. I've also learned somthing new today as apparently 4°C (40°F) is the magic temperature for water. Water reaches its maximum density at 4°C (40°F). As it cools further and freezes into ice, it actually becomes less dense. On the other hand, most substances are most dense in their solid (frozen) state than in their liquid state. Water is different because of hydrogen bonding. http://chemistry.about.com/od/chemistryfaqs/f/icefloats.htm Link to comment Share on other sites More sharing options...
Guest sibon Posted June 20, 2010 Share Posted June 20, 2010 Molecules are more densely packed in a liquid than in a gas so it weighs more ………….. right got that , if the molecules become even more densely packed they will form a solid which following the logic would be heavier still so how come ice floats. A fantastic accident of Chemistry. Your reasoning is correct and most solids are denser than their respective liquids. Water is different though. It gets denser as it cools until it reaches 4 degrees celcius, after which, it gets less dense. This is because of the way that the molecules pack together as it becomes solid. If this didn't happen, ponds and lakes would freeze from the bottom upwards. That would make fishing rather easy in a severe winter:D Link to comment Share on other sites More sharing options...
Lockjaw Posted June 20, 2010 Share Posted June 20, 2010 I disagree. It needs more definition. For a start, the question doesn't refer to gases, it merely says "Why is water heavy?". That question has so many possible answers that it is pretty meaningless. You're starting to sound like a physicist... ETA. Congrats. on the status upgrade. How much time have you spent trying to think of a witty tag line thingy? Link to comment Share on other sites More sharing options...
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