Originally posted by wolfgang59 Any impurities in water will lower the temperature at which it freezes (hence polar seas are sub-zero) and its why we put salt on our paths.
Hard tap-water contains lots of calcium salts (amongst others) and this will affect the freezing point. Boling the water first will have no effect.
Some tap-water has 'temporary' hardness cause by bicarbonate m ...[text shortened]... xperiment maybe to COMPARE water from different sources regarding the boiling/freezing thing.
Another possibility is that since hot water expands, a volume of cold water will actually contain more water than an equal volume of hot water. Thus it may need less energy removed to freeze.
Originally posted by AThousandYoung Another possibility is that since hot water expands, a volume of cold water will actually contain more water than an equal volume of hot water. Thus it may need less energy removed to freeze.
Originally posted by AThousandYoung Another possibility is that since hot water expands, a volume of cold water will actually contain more water than an equal volume of hot water. Thus it may need less energy removed to freeze.
"... a volume of cold water will actually contain more water than an equal volume of hot water ..."
There is exactly the same mass of water. Only density is less. Energy needed is defined by mass.
Originally posted by Sam The Sham Actually the myth is that water that has just been brought to a full boil, then allowed to cool, will freeze faster than water at the same temperature that hasn't. And I don't know if it's true or not.
The water is allowed to cool. Both the previously boiled water and non-boiled water go into the fridge at the same time. Same density. Same mass.
The phenomenon is purely to do with relative purities. (pun intended)
Originally posted by FabianFnas How much doesl the relative volume change for each centigrade colder at, say, 2 degree Celsius?
GRANNY is performing this experiment as you sit and ponder. So far, nothing has reached room temp. I assure you that iam using the same quility controls that i used when i worked at Bell Labs.
Originally posted by smw6869 GRANNY is performing this experiment as you sit and ponder. So far, nothing has reached room temp. I assure you that iam using the same quility controls that i used when i worked at Bell Labs.
Granny
Both samples are at room temp (60degrees)
Placed in freezer, next to each other. Time: 5:27.
Time: 6:40 - cold water- some ice crystals on top.
hot water - no ice crystals.
Originally posted by FabianFnas How much doesl the relative volume change for each centigrade colder at, say, 2 degree Celsius?
At that temperature the volume begins to increase as it gets colder because the structure of ice requires expansion of the water as it freezes. However we're not talking about cold and colder water. We're discussing hot vs cold water; cold as in cold from the tap, not cold from the freezer.
my own mythbusters
28 Dec '07 04:58
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