Phoenix surface mission

centsworth_II · Aug 25, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Isn't the lander projected to be berried in ice during the winter? Posted by bearack</DIV> Yes, buried in dry ice (CO2).  You could say that the chance of Phoenix surviving the winter is zero, but it is human nature to allow for the possibility of a miracle. Quoting Peter Smith of the University of Arizona, the Phoenix mission Principal Investigator:"…as winter comes to the spacecraft and the sun sets, it gets extremely cold -- so cold that it actually freezes out the carbon dioxide atmosphere into dry ice. And you get a layer of dry ice that actually encases the spacecraft.... at that point, the electronics would be stressed past the point where they're guaranteed to work and it'd be a miracle if they survive through that winter, but we may try and listen in the spring and summer of the next year just to see if it did. I suspect it won't...." http://www.edn.com/blog/1470000147/post/1750028375.html?nid=3002     <div class="Discussion_UserSignature"> </div>

3488 · Aug 25, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Isn't the lander projected to be berried in ice during the winter?  If the case, I'm sure there would be significant damage and the likely hood of reestablishing contact would be zero. Posted by bearack</DIV>Hi Tim,Yes most likely that Phoenix will be damaged beyond repair. Solar arrays could snap, soldering will contract & snap, batteries will be unable to hold sufficient charge, even IF they could be recharged. Temperatures will drop to around -135 C / -211 F. Sun will not rise at all between 5th April - 7th July 2009. Replying to: <DIV CLASS='Discussion_PostQuote'>Yes, buried in dry ice (CO2).  You could say that the chance of Phoenix surviving the winter is zero, but it is human nature to allow for the possibility of a miracle. Quoting Peter Smith of the University of Arizona, the Phoenix mission Principal Investigator:"…as winter comes to the spacecraft and the sun sets, it gets extremely cold -- so cold that it actually freezes out the carbon dioxide atmosphere into dry ice. And you get a layer of dry ice that actually encases the spacecraft.... at that point, the electronics would be stressed past the point where they're guaranteed to work and it'd be a miracle if they survive through that winter, but we may try and listen in the spring and summer of the next year just to see if it did. I suspect it won't...." http://www.edn.com/blog/1470000147/post/1750028375.html?nid=3002     Posted by centsworth_II</DIV>Hi centsworth_II. Yes, I suspect that too. Mind you Phoenix has a LAZARUS routine programmed in, thus if Phoenix is undamaged & when enough sunlight strikes the arrays, she will automatically call Earth to tell us she's survived.I have put in a request to the MRO HiRISE team to repeatedly image the Phoenix site after contact is lost to monitor has the CO2 ice encroaches the area & encases Phoenix, likewise in the Spring as the ice retreats & Phoenix is released from her icy tomb. HiRISE can certainly see if the arrays have snapped off, if the ice has moved Phoenix, etc .Replying to: <DIV CLASS='Discussion_PostQuote'>The likelyhood of being able to recontact Phoenix after winter is near zero, but they may try anyway.  According to this, Spring for Phoenix will start in October 2009. Posted by centsworth_II</DIV>I think I had posted some dates on here a ehile back of the Martian seasons for this & next year. The dates I had are from a spreadsheet I had set up myself using only a start date & the rest I figured out muself. Emily's dates & mine match up perfectly. Shows I got it right!!! Below. Penultimate Sol of Primary Mission. Another look at Holy Cow. Lighting is different this time as is late morning rather than mid afternoon as on other sols Holy Cow was imaged. Note the icy globules on the leg of Phoenix are larger again than last time.Sol 89 Holy Cow. <img src="http://sitelife.space.com/ver1.0/Content/images/store/3/6/f37b0c05-35d6-4026-b60f-1cf02538988e.Medium.jpg" alt="" />Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

3488 · Aug 25, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Operation TILTWhen the irradiance gets lower, we can buy some additonal operational time, perhaps a month, by using the arm to lift one side of Pheonix and tilt it so that the solar panels face the sun at a much better angle.  This manuver will cause some risk, as it has never been done before.  And the three legs are not exactly in optimal position with two legs facing the sun, so the arm will need to be used first to drag/rotate the craft a bit to turn it about 30-45 degrees.   (This idea was first proposed by someone on UMSF)I think we should use the arm to drag Pheonix anyways, before all goes silent.  This would allow access to the remarkable ice patch directly under the lander. Posted by silylene</DIV>Hi silylene, I had thought of that before it appeared on UMSF, but did not promote it as I thought others would think I'm being stupid & it is a risky maneuver as that arm has tremendous strength. Perhaps I should have said!!!!!!!! I think the drag might work, as the foot pads do not appear to be wedged against rocks etc. How far would Phoenix have o be dragged? Two metres?? Quite a long way, but possible in small incremental stages over the duration of a few sols.Another better exposed image of Holy Cow, Sol 89. <img src="http://sitelife.space.com/ver1.0/Content/images/store/8/13/d8bee2fe-828c-4e1d-bdf0-cb07e4262ce2.Medium.jpg" alt="" />  Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

baulten · Aug 25, 2008

Do we really know exactly how much CO2 will condense out during the winter?  If it's not enough to break off the solar arrays or other equipment I'd say that it would have a much greater chance of survival.

3488 · Aug 25, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Do we really know exactly how much CO2 will condense out during the winter?  If it's not enough to break off the solar arrays or other equipment I'd say that it would have a much greater chance of survival. Posted by baulten</DIV>Hi baulten, The depth of Winter CO2 ice here appears to vary between a minimun of 2 metres (6.5 feet) & can be as deep as 10 metres (33 feet).Phoenix is going to get buried in CO2 ice, of that fact there is no doubt. What we do not know with any certaintly are the effects on Phoenix that will have.Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

baulten · Aug 25, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi baulten, The depth of Winter CO2 ice here appears to vary between a minimun of 2 metres (6.5 feet) & can be as deep as 10 metres (33 feet).Phoenix is going to get buried in CO2 ice, of that fact there is no doubt. What we do not know with any certaintly are the effects on Phoenix that will have.Andrew Brown.  Posted by 3488</DIV>Ah, okay.  I was unsure how much we knew about the varying depths of dry ice across the north and south poles over the seasons.  Maybe enough will build up under the arrays to keep them from breaking <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-wink.gif" border="0" alt="Wink" title="Wink" />

3488 · Aug 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Ah, okay.  I was unsure how much we knew about the varying depths of dry ice across the north and south poles over the seasons.  Maybe enough will build up under the arrays to keep them from breaking Posted by baulten</DIV>Good point baulten. I wonder though if ice will build up on top of the arrays before they are propt up from beneath? Does the ice move after Phoenix is encased? All these can snap the arrays off.Hi all,Here we are, final Sol of Primary Mission has commenced.Sol 90 at 00:51 LMST Sun on the horizon. NNW. <img src="http://sitelife.space.com/ver1.0/Content/images/store/8/2/68e5ae5f-8f84-40ec-9287-7a0bdc943d50.Medium.jpg" alt="" />Alt -16.74 deg Azm 126.05 deg Sol 90 at 01:23 HRS LMST. <img src="http://sitelife.space.com/ver1.0/Content/images/store/15/6/4fe57e83-f328-416f-b6f8-f57120054d7d.Medium.jpg" alt="" /> Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

bearack · Aug 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Good point baulten. I wonder though if ice will bui;ld up on top of the arrays before they are propt up from beneath? Does the ice move after Phoenix is encased? All these can snap the arrays off.Hi all,Here we are, final Sol of Primary Mission has commenced.Sol 90 at 00:51 LMST Sun on the horizon. NNW.Alt -16.74 deg Azm 126.05 deg Sol 90 at 01:23 HRS LMST.Andrew Brown. Posted by 3488</DIV> I would suspect if there is any trace of water ice that there would be expansion which could rip the lander in half.  Just a thought though.  <div class="Discussion_UserSignature"> <img id="06322a8d-f18d-4ab1-8ea7-150275a4cb53" src="http://sitelife.space.com/ver1.0/Content/images/store/6/14/06322a8d-f18d-4ab1-8ea7-150275a4cb53.Large.jpg" alt="blog post photo" /> </div>

3488 · Aug 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I would suspect if there is any trace of water ice that there would be expansion which could rip the lander in half.  Just a thought though.  Posted by bearack</DIV>Another good point Tim.I suppose it depends on how much H2O ice there will be & how / if it can penerate the pumbing, etc of Phoenix, before expanding.I do know that CO2 does not expand it is frozen form, H2O IIRC is unique in this respect (wouldn't have thought I have Bs in both Chemistry & Physics & As in Geology & Planetary Science, yet so much I cannot remember. I'm sad & pathetic really).But you do raise a very good point & in all fairness, I think your theory may be part of Phoenix's undoing. There will be more H2O ice forming, before the CO2 starts to crash out, & Phoenix is moving ahead not into a more 'dangerous' part of the Martian Year for a lander of that type.Hi all,Some more from Sol 90. Sol 90 at 00:57 LMST Sun on the horizon. NNW. <img src="http://sitelife.space.com/ver1.0/Content/images/store/13/9/3d11f56c-5ce1-43a8-995c-0d2733132267.Medium.jpg" alt="" />Holy Cow Sol 90 at 09:42 LMST. <img src="http://sitelife.space.com/ver1.0/Content/images/store/15/0/ef0cca53-901f-406f-9046-68a1e5a8dfb5.Medium.jpg" alt="" />Alt -16.74 Azm 126.05 deg Sol 90 at 03:37 LMST. <img src="http://sitelife.space.com/ver1.0/Content/images/store/5/4/156b638f-7441-4614-8482-7cd02b371a47.Medium.jpg" alt="" />Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Aug 26, 2008

August 25, 2008 -- The next sample of Martian soil being grabbed for analysis is coming from a trench about three times deeper than any other trench NASA's Phoenix Mars Lander has dug. On Tuesday, Aug. 26, the spacecraft will finish the 90 Martian days (or "sols") originally planned as its primary mission and will continue into a mission extension through September, as announced by NASA in July. Phoenix landed on May 25. "As we near what we originally expected to be the full length of the mission, we are all thrilled with how well the mission is going," said Phoenix Project Manger Barry Goldstein of NASA's Jet Propulsion Laboratory, Pasadena, Calif. Phoenix's main task for Sol 90 is to scoop up a sample of soil from the bottom of a trench called "Stone Soup," which is about 18 centimeters, or 7 inches deep. On a later sol, the lander's robotic arm will sprinkle soil from the sample into the third cell of the wet chemistry laboratory. This deck-mounted laboratory, part of Phoenix's Microscopy, Electrochemistry and Conductivity Analyzer (MECA), has previously used two of its four soil-testing cells. "In the first two cells we analyzed samples from the surface and the ice interface, and the results look similar. Our objective for Cell 3 is to use it as an exploratory cell to look at something that might be different," said JPL's Michael Hecht, lead scientist for MECA. "The appeal of Stone Soup is that this deep area may collect and concentrate different kinds of materials." Stone Soup lies on the borderline, or natural trough, between two of the low, polygon-shaped hummocks that characterize the arctic plain where Phoenix landed. The trench is toward the left, or west, end of the robotic arm's work area on the north side of the lander. When digging near a polygon center, Phoenix has hit a layer of icy soil, as hard as concrete, about 5 centimeters, or 2 inches, beneath the ground surface. In the Stone Soup trench at a polygon margin, the digging has not yet hit an icy layer like that. "The trough between polygons is sort of a trap where things can accumulate," Hecht said. "Over a long timescale, there may even be circulation of material sinking at the margins and rising at the center." http://phoenix.lpl.arizona.edu/08_25_pr.php <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

baulten · Aug 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I would suspect if there is any trace of water ice that there would be expansion which could rip the lander in half.  Just a thought though.  Posted by bearack</DIV>Won't the water be condensing out at such a low temperature that it won't undergo the expansion associated with water ice in our (comparitively speaking) warm and thick atmosphere?

3488 · Aug 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>August 25, 2008 -- The next samp.......................... Posted by MeteorWayne</DIV> Cheers Wayne, We'll soon see what ther polygon boundary will reveal. Very interesting. Replying to: <DIV CLASS='Discussion_PostQuote'>Won't the water be condensing out at such a low temperature that it won't undergo the expansion associated with water ice in our (comparitively speaking) warm and thick atmosphere? Posted by baulten</DIV>Hi Baulten,If the frost is like a diamond dust 'snow', then the ice crystals IIRC will already be in their final size. If the frost form insitu on Phoenix, freezes directly from vapour to ice, then that could cause problems???? Hi all, The Sun DID set behind a suspected Pingo in the north. Because of that rise, the Sun did appear to set. However, if the horizon was level, then the first 'proper' Sunset is this coming Saturday. This is actually quite complicated to pin down exactly. The horizon slopes to the South, Phoenix is approx 3,500 metres below the Datum Line & the northern horizon is not 100% level & has a few 'bumps'. I am probably giving the impression that I do not know what I'm talking about.<img src="http://sitelife.space.com/ver1.0/Content/images/store/10/11/eacb4d60-c6f4-4585-8bb8-8453f8cbc435.Medium.gif" alt="" /> <img src="http://sitelife.space.com/ver1.0/Content/images/store/5/14/2556b5b6-5fcc-43ca-be46-560408df09e1.Medium.gif" alt="" />   <img src="http://sitelife.space.com/ver1.0/Content/images/store/4/1/045610dd-6e8b-4096-81b0-723ecf1b50d7.Medium.gif" alt="" />  Sun setting & rising behind a bump, a possible Pingo in the north? Sol 90. <img src="http://sitelife.space.com/ver1.0/Content/images/store/5/5/3523495e-b061-426d-a552-3aeaa4a7b80a.Medium.jpg" alt="" />  Work Area trenches as of Sol 90. <img src="http://sitelife.space.com/ver1.0/Content/images/store/4/14/d43d5f9c-f0d0-4926-bec9-396b34257b77.Medium.jpg" alt="" />  Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

bearack · Aug 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Won't the water be condensing out at such a low temperature that it won't undergo the expansion associated with water ice in our (comparitively speaking) warm and thick atmosphere? Posted by baulten</DIV> Water ice expands as it gets colder.  I think it only stops expanding at absolute zero (-273 C) <div class="Discussion_UserSignature"> <img id="06322a8d-f18d-4ab1-8ea7-150275a4cb53" src="http://sitelife.space.com/ver1.0/Content/images/store/6/14/06322a8d-f18d-4ab1-8ea7-150275a4cb53.Large.jpg" alt="blog post photo" /> </div>

3488 · Aug 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Water ice expands as it gets colder.  I think it only stops expanding at absolute zero (-273 C) Posted by bearack</DIV>Hi Tim, There's this,<pre>No, ice does not expand as it gets colder. When water freezes, it increases in volume about 9%. The ice then shrinks as the temperature decreases. The shrinkage is tiny, about 0.4% going from 30F to -50F.............................,</pre><pre>Full quote here.</pre><pre>Hi all, </pre><pre>Weather report for Sol 87.</pre><pre><img src="http://sitelife.space.com/ver1.0/Content/images/store/2/3/e24d86a0-d338-48d7-93f6-90ad424be058.Medium.jpg" alt="" /> </pre><pre>Andrew Brown. </pre> <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

baulten · Aug 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Tim, There's this,No, ice does not expand as it gets colder.When water freezes, it increases in volume about 9%. The ice then shrinksas the temperature decreases. The shrinkage is tiny, about 0.4% going from30F to -50F.............................,Full quote here.Hi all, Weather report for Sol 87. Andrew Brown.  Posted by 3488</DIV>See, that's what I thought.  I thought that the colder it got, the ice contracted.  It only expanded because of the way it freezes, therefore it should contract as temperature further decreases after 32F/0C.  Sounds like I'm right.

3488 · Aug 27, 2008

Sol 91. First Sol of extended mission.   Looks like the extended mission kicks off with frost monitoring. -16.74 Alt, 126.05 Azm Sol 91 at 01.12 HRS LMST.  <img src="http://sitelife.space.com/ver1.0/Content/images/store/11/11/1bedd140-dc70-4de7-9b98-4b1c33d3ecb9.Medium.jpg" alt="" />  -16.74 Alt, 126.05 Azm Sol 91 at 01.20 HRS LMST. <img src="http://sitelife.space.com/ver1.0/Content/images/store/11/12/7b9fcc94-1fc3-49f9-9c70-8795f79e2bd6.Medium.jpg" alt="" />  Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

freya · Aug 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Sol 91. First Sol of extended mission.   Looks like the extended mission kicks off with frost monitoring. -16.74 Alt, 126.05 Azm Sol 91 at 01.12 HRS LMST.   -16.74 Alt, 126.05 Azm Sol 91 at 01.20 HRS LMST.  Andrew Brown.  Posted by 3488</DIV>Hey all, just a thought, would it be best to open a new thread, Pheonix Etxtended Mission, or should we see this thread through to the end? <div class="Discussion_UserSignature"> </div>

bearack · Aug 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Tim, There's this,No, ice does not expand as it gets colder.When water freezes, it increases in volume about 9%. The ice then shrinksas the temperature decreases. The shrinkage is tiny, about 0.4% going from30F to -50F.............................,Full quote here.Hi all, Weather report for Sol 87. Andrew Brown.  Posted by 3488</DIV> Thanks for the correction.  I'll have to track down my old physics teacher and give him a grade of F!Edited! <div class="Discussion_UserSignature"> <img id="06322a8d-f18d-4ab1-8ea7-150275a4cb53" src="http://sitelife.space.com/ver1.0/Content/images/store/6/14/06322a8d-f18d-4ab1-8ea7-150275a4cb53.Large.jpg" alt="blog post photo" /> </div>

bearack · Aug 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Tim, There's this,No, ice does not expand as it gets colder.When water freezes, it increases in volume about 9%. The ice then shrinksas the temperature decreases. The shrinkage is tiny, about 0.4% going from30F to -50F.............................,Full quote here.Hi all, Weather report for Sol 87. Andrew Brown.  Posted by 3488</DIV> Hmm, I seem to be getting a conflict of answers from the field of Physics.  Some say after the 9% expansion there is a .04% reduction the colder it gets while some believe there is no reduction, but further expansion.  Granted, I'm not sure the validity of the persons credentials, but it sounds somewhat legit to what my professor taught me.What the BA Physics says is wrong. Water contracts like ordinary substances up to a temperature of 39 Fahrenheit (4 degree Celsius) below which it starts expanding rather than contracting because of its molecular structure, it has an elastic hydrogen bond and a crystalline structure. When water cools it tries to form a crystalline lattice configuration that stretches the the hydrogen bond, which push the water molecules away from each other. Say water taken at 10 degree C when cooled will contract until it reaches a temperature of 4 degree C. Once it reaches 4 C the components of the hydrogen bond present in its molecules stretch which repel other molecules hence its volume increases. The net increase in volume is about 9% which reduces its density. If you want to observe how it actually occurs, fill a bottle (a larger one so the difference in level is appreciable) with water and carefully observe that initially water will contract and the water in liquid state will appear somewhat less then you actually filled it and later it will expand once it reaches 4 C (39 F) that makes your bottle feel like its busting. Have a thermometer handy to see the temperature at which it actually starts expanding.  <div class="Discussion_UserSignature"> <img id="06322a8d-f18d-4ab1-8ea7-150275a4cb53" src="http://sitelife.space.com/ver1.0/Content/images/store/6/14/06322a8d-f18d-4ab1-8ea7-150275a4cb53.Large.jpg" alt="blog post photo" /> </div>

centsworth_II · Aug 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>...what my professor taught me.What the BA Physics says is wrong. Water contracts like ordinary substances up to a temperature of 39 Fahrenheit (4 degree Celsius) below which it starts expanding rather than contracting because of its molecular structure, it has an elastic hydrogen bond and a crystalline structure. When water cools it tries to form a crystalline lattice configuration that stretches the the hydrogen bond, which push the water molecules away from each other. Say water taken at 10 degree C when cooled will contract until it reaches a temperature of 4 degree C. Once it reaches 4 C the components of the hydrogen bond present in its molecules stretch which repel other molecules hence its volume increases. The net increase in volume is about 9% which reduces its density. If you want to observe how it actually occurs, fill a bottle (a larger one so the difference in level is appreciable) with water and carefully observe that initially water will contract and the water in liquid state will appear somewhat less then you actually filled it and later it will expand once it reaches 4 C (39 F) that makes your bottle feel like its busting. Have a thermometer handy to see the temperature at which it actually starts expanding.  Posted by bearack</DIV> I'm confused.  Is the paragraph in italics what your professor taught you? If so, there is no problem.  All it describes is the expansion of water as it cools from 4 degrees C to freezing (0 degrees C).  It says nothing about what happens to the volume of the frozen water if it cools below 0 degrees C.My description, for the record:  As water cools, the molecules,reduced in energy and activity, settle down closer to each other and the volume contracts.  The transformation of water into ice requires that the molecules arange themselves into a crystal pattern which fixes their distance from each other and leads to an expansion in volume.  Once the ice is formed, the expansion is complete.  If the ice is cooled further, the energy goes down and the separation of the molecules in the ice crystal structure will decrease slightly leading to a slight reduction in volume.Again, the expansion of freezing water is due solely to the rearrangement of the water molecules into the ice crystal structure.  Once that process is complete, there is no further expansion.  <div class="Discussion_UserSignature"> </div>

silylene old · Aug 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I'm confused.  Is the paragraph in italics what your professor taught you? If so, there is no problem.  All it describes is the expansion of water as it cools from 4 degrees C to freezing (0 degrees C).  It says nothing about what happens to the volume of the frozen water if it cools below 0 degrees C.My description, for the record:  As water cools, the molecules,reduced in energy and activity, settle down closer to each other and the volume contracts.  The transformation of water into ice requires that the molecules arange themselves into a crystal pattern which fixes their distance from each other and leads to an expansion in volume.  Once the ice is formed, the expansion is complete.  If the ice is cooled further, the energy goes down and the separation of the molecules in the ice crystal structure will decrease slightly leading to a slight reduction in volume.Again, the expansion of freezing water is due solely to the rearrangement of the water molecules into the ice crystal structure.  Once that process is complete, there is no further expansion.  Posted by centsworth_II</DIV> Correct, and what Andrew quoted. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

bearack · Aug 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I'm confused.  Is the paragraph in italics what your professor taught you? If so, there is no problem.  All it describes is the expansion of water as it cools from 4 degrees C to freezing (0 degrees C).  It says nothing about what happens to the volume of the frozen water if it cools below 0 degrees C.My description, for the record:  As water cools, the molecules,reduced in energy and activity, settle down closer to each other and the volume contracts.  The transformation of water into ice requires that the molecules arange themselves into a crystal pattern which fixes their distance from each other and leads to an expansion in volume.  Once the ice is formed, the expansion is complete.  If the ice is cooled further, the energy goes down and the separation of the molecules in the ice crystal structure will decrease slightly leading to a slight reduction in volume.Again, the expansion of freezing water is due solely to the rearrangement of the water molecules into the ice crystal structure.  Once that process is complete, there is no further expansion.  Posted by centsworth_II</DIV>I didn't mean to get the thread off topic.  I was just confused to what my professor said.  Once I delved into it a little further, there is a consensus of a slight reduction as ice cools further.  Sorry for the confusion and misdirection of the thread.  Never was good at physics.....trigonometry.....hell, grammar for that matter.  I should have focussed less on where my beer was coming from that evening and more on the important stuff.

centsworth_II · Aug 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I didn't mean to get the thread off topic.... Posted by bearack</DIV> Well, it looks like we've got a new Phoenix thread anyway.  Tough stuff, physics.<img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /> <div class="Discussion_UserSignature"> </div>

centsworth_II · Aug 27, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Correct, and what Andrew quoted. Posted by silylene</DIV> It's good to have a real scientist around!<img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /> <div class="Discussion_UserSignature"> </div>

MeteorWayne · Aug 31, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>When will we see the first real deep layers of ice ?A complete white landscape Wouldn't it be a great first Martian Xmas card Posted by efron_24</DIV> That question would be better off in the other thread, where it is being, has been, and will be discussed.

<div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Phoenix surface mission

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