23 Dec 07
So in my AP Physics class we were talking about what we should do for the 3 weeks after the AP test in may. My teacher decided that we were going to conduct our very own mythbusters. However, we haven't really found a myth that we can really use. Does anyone have any urban legends/myths that they wish they could test?
24 Dec 07
Originally posted by TDR1Can an airplane on a backwards-running treadmill still take off?!? 😵
So in my AP Physics class we were talking about what we should do for the 3 weeks after the AP test in may. My teacher decided that we were going to conduct our very own mythbusters. However, we haven't really found a myth that we can really use. Does anyone have any urban legends/myths that they wish they could test?
(If you actually get to try this, please please PLEASE post the results here so we can get rid of those annoying airplane/treadmill threads...)
25 Dec 07
Originally posted by Coconut😴
Actually i did one.
http://video.google.com/videoplay?docid=8162302262003580758
...what the?!? Oh...a little long, but interesting. The experiment could have been controlled a bit better too, but the results are as you'd expect. Can you get extra credit for a follow-up?
26 Dec 07
1 edit
Originally posted by coquetteActually 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.
A glass of warm water placed in the freezer freezes faster than a glass of cold water.
Anything dealing with astrology, tarot, charms, predicting lottery numbers . . .anything like that.
27 Dec 07
Originally posted by Sam The ShamWhat are you supposed to do with boiling ice cubes?
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.
Granny
27 Dec 07
Originally posted by Sam The ShamIf it is true, it probably has something to do with the purity of the water. Depending on how many particles are in the water, I think it can effect freezing time. Especially if there are no particles in the water, then it can't freeze. Not really sure though, just going on what little knowledge I have and filling the whole with logic.
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.
27 Dec 07
Originally posted by GalaxyShieldAny 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.
If it is true, it probably has something to do with the purity of the water. Depending on how many particles are in the water, I think it can effect freezing time. Especially if there are no particles in the water, then it can't freeze. Not really sure though, just going on what little knowledge I have and filling the whole with logic.
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 molecules in solution. Not sure of chemistry but when heated (I don't think actual boiling is necessary) these bicarbonates change into insoluble carbonates and leave the nasty scale on the inside of your kettle.
THEREFORE providing the initial tap-water contained bicarbonates boiling will remove some of the dissolved salts making the water EASIER to freeze.
An interesting experiment maybe to COMPARE water from different sources regarding the boiling/freezing thing.
27 Dec 07
Originally posted by wolfgang59http://encyclopedia.thefreedictionary.com/Water+softness
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.
28 Dec 07
Originally posted by wolfgang59Listen up dudes. Granny has the correct answer, again. If you pour hot water into an 8oz. glass, and pour cold water into an 8oz glass (to the top); the hot water glass has less water in it than the cold water glass. There is more space between the water molecules therefore less water freezes before more water. Simple physics. Case closed. And, as we say in texas, if it isn't true ....it should be.
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.
GRANNY.
28 Dec 07
The point of boiling the water first, then having a race to freeze it is interesting. I don't believe that any of the theorists have it right, though.
The point, I think, would go to the solubility of gases in water. Atmospheric gases are not as soluble in hot water as in cold water, and "pure water," as mentioned above, would be water with NO impurities, including oxygen, and that would freeze faster.
So, you have your project.