Why does the Resistance of a Hot Dog decrease as it heats up?
ScottH, Fri Apr 14 2017, 08:48AMWhen I run 120v through a hot dog, it draws 1.2A while its cold. As it starts to cook from the electricity, it draws more and more amps until it bursts, peaking at 3.3A.
Doesn't the resistance increase as a resistor (hot dog or filament) heats up? Is there another reason why this happens?
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
BigBad, Sat Apr 15 2017, 12:40AM
You might be carbonising it. Carbon has low resistance.
Also, dunno if liquidating the fats, particularly if they have carbon or metals from the electrodes in them will probably reduce the resistance.
BigBad, Sat Apr 15 2017, 12:40AM
You might be carbonising it. Carbon has low resistance.
Also, dunno if liquidating the fats, particularly if they have carbon or metals from the electrodes in them will probably reduce the resistance.
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
klugesmith, Sat Apr 15 2017, 12:57AM
Metals generally have positive TCR (temperature coefficient of resistance) values.
Aqueous electrolytes generally have negative TCR's.
The Internet can help you learn more.
p.s. It's good to see you measuring things and reporting results. Can we see a picture of the meter that gave you those AC Amps readings? What's its most sensitive AC Milliamperes range? What are its highest and lowest AC Volts ranges? This is related to your thread about measuring AC voltages up to a few thousand.
Speaking of hot dogs: Ordinary domestic Ground Fault Circuit Interrupting outlets can be tripped with AC current conducted through live human fingers on purpose. A thing to which I can personally attest, and I am no torturer.
klugesmith, Sat Apr 15 2017, 12:57AM
Metals generally have positive TCR (temperature coefficient of resistance) values.
Aqueous electrolytes generally have negative TCR's.
The Internet can help you learn more.
p.s. It's good to see you measuring things and reporting results. Can we see a picture of the meter that gave you those AC Amps readings? What's its most sensitive AC Milliamperes range? What are its highest and lowest AC Volts ranges? This is related to your thread about measuring AC voltages up to a few thousand.
Speaking of hot dogs: Ordinary domestic Ground Fault Circuit Interrupting outlets can be tripped with AC current conducted through live human fingers on purpose. A thing to which I can personally attest, and I am no torturer.
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
Bjørn, Sun Apr 16 2017, 08:17PM
When it gets hot, it may cause the electrodes to be covered with salty water that conducts better than fat. Many things will happen that can affect the resistance.
Human skin can also drop significantly in resistance when a current is applied because of how electrolytes behave when a voltage is applied.
Bjørn, Sun Apr 16 2017, 08:17PM
When it gets hot, it may cause the electrodes to be covered with salty water that conducts better than fat. Many things will happen that can affect the resistance.
Human skin can also drop significantly in resistance when a current is applied because of how electrolytes behave when a voltage is applied.
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
Proud Mary, Sun Apr 16 2017, 09:08PM
The hot dog very likely contains sodium chloride, sodium nitrite, and sodium nitrate, which would take the form of a mixed electrolyte when a potential difference is applied.
At the anode , chloride (Cl-) is oxidized to chlorine whilst at the cathode water is reduced to hydroxide and hydrogen gas yielding an aqueous solution of sodium hydroxide and chlorine gas with some production of chlorate as the temperature rises.
Migrating metal ions stripped from the electrodes could result in the production of an array of organometallic compounds produced from the reaction of the mixed electrolyte, chlorine, and sodium hydroxide on the organic sausage material.
The electrolysis of the aqueous sodium nitrate could be expected to produce some pernitrates. Under sufficient thermal dehydration, the nitrates might deflagrate accelerating the carbonisation of the sausage, which would thus become more conductive, until thermal runaway occurs.
The deposition of the many reaction products inside the sausage would very likely not be homogenous, with some eletrophoresis effects producing linear banding separation of some of the chemistry along the length of the sausage, perhaps having the effect that the electrolysed sausage would be more toxic in some parts than others.
Proud Mary, Sun Apr 16 2017, 09:08PM
The hot dog very likely contains sodium chloride, sodium nitrite, and sodium nitrate, which would take the form of a mixed electrolyte when a potential difference is applied.
At the anode , chloride (Cl-) is oxidized to chlorine whilst at the cathode water is reduced to hydroxide and hydrogen gas yielding an aqueous solution of sodium hydroxide and chlorine gas with some production of chlorate as the temperature rises.
Migrating metal ions stripped from the electrodes could result in the production of an array of organometallic compounds produced from the reaction of the mixed electrolyte, chlorine, and sodium hydroxide on the organic sausage material.
The electrolysis of the aqueous sodium nitrate could be expected to produce some pernitrates. Under sufficient thermal dehydration, the nitrates might deflagrate accelerating the carbonisation of the sausage, which would thus become more conductive, until thermal runaway occurs.
The deposition of the many reaction products inside the sausage would very likely not be homogenous, with some eletrophoresis effects producing linear banding separation of some of the chemistry along the length of the sausage, perhaps having the effect that the electrolysed sausage would be more toxic in some parts than others.
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
Conundrum, Mon Apr 17 2017, 06:46AM
Heh, nice!
Wonder if it is indeed the metal that is changing resistance?
I would do a further test with Pt or Ir or something refractive,
and compare results.
Conundrum, Mon Apr 17 2017, 06:46AM
Heh, nice!
Wonder if it is indeed the metal that is changing resistance?
I would do a further test with Pt or Ir or something refractive,
and compare results.
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
ScottH, Mon Apr 17 2017, 01:27PM
Awesome explanation! There is a lot more going on inside of the hot dog than I expected. Thanks.
ScottH, Mon Apr 17 2017, 01:27PM
Proud Mary wrote ...
The hot dog very likely contains sodium chloride, sodium nitrite, and sodium nitrate, which would take the form of a mixed electrolyte when a potential difference is applied.
At the anode , chloride (Cl-) is oxidized to chlorine whilst at the cathode water is reduced to hydroxide and hydrogen gas yielding an aqueous solution of sodium hydroxide and chlorine gas with some production of chlorate as the temperature rises.
Migrating metal ions stripped from the electrodes could result in the production of an array of organometallic compounds produced from the reaction of the mixed electrolyte, chlorine, and sodium hydroxide on the organic sausage material.
The electrolysis of the aqueous sodium nitrate could be expected to produce some pernitrates. Under sufficient thermal dehydration, the nitrates might deflagrate accelerating the carbonisation of the sausage, which would thus become more conductive, until thermal runaway occurs.
The deposition of the many reaction products inside the sausage would very likely not be homogenous, with some eletrophoresis effects producing linear banding separation of some of the chemistry along the length of the sausage, perhaps having the effect that the electrolysed sausage would be more toxic in some parts than others.
The hot dog very likely contains sodium chloride, sodium nitrite, and sodium nitrate, which would take the form of a mixed electrolyte when a potential difference is applied.
At the anode , chloride (Cl-) is oxidized to chlorine whilst at the cathode water is reduced to hydroxide and hydrogen gas yielding an aqueous solution of sodium hydroxide and chlorine gas with some production of chlorate as the temperature rises.
Migrating metal ions stripped from the electrodes could result in the production of an array of organometallic compounds produced from the reaction of the mixed electrolyte, chlorine, and sodium hydroxide on the organic sausage material.
The electrolysis of the aqueous sodium nitrate could be expected to produce some pernitrates. Under sufficient thermal dehydration, the nitrates might deflagrate accelerating the carbonisation of the sausage, which would thus become more conductive, until thermal runaway occurs.
The deposition of the many reaction products inside the sausage would very likely not be homogenous, with some eletrophoresis effects producing linear banding separation of some of the chemistry along the length of the sausage, perhaps having the effect that the electrolysed sausage would be more toxic in some parts than others.
Awesome explanation! There is a lot more going on inside of the hot dog than I expected. Thanks.
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
Proud Mary, Mon Apr 17 2017, 04:12PM
Thank you for your kind words, Mr Scott. I thought this much the most interesting experiment which I have seen in this forum for a long time.
To test my theory of electrophoresis, the sausage should be chilled to -40°C or so, and then sliced up along its length with a microtome (think ultra-fine salami slicer for microscopy sections).
The individual slices can then (at ridiculous cost and labour) be analysed, and a plot prepared of the distribution of the constituents along the length of the sausage.
Good fun thinking about it. Thank you.
Proud Mary, Mon Apr 17 2017, 04:12PM
Thank you for your kind words, Mr Scott. I thought this much the most interesting experiment which I have seen in this forum for a long time.
To test my theory of electrophoresis, the sausage should be chilled to -40°C or so, and then sliced up along its length with a microtome (think ultra-fine salami slicer for microscopy sections).
The individual slices can then (at ridiculous cost and labour) be analysed, and a plot prepared of the distribution of the constituents along the length of the sausage.
Good fun thinking about it. Thank you.
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
Dr. Slack, Mon Apr 17 2017, 06:33PM
Tracking chemical composition as a function of length after electrophoresis sounds a bit like chromhotdography
Dr. Slack, Mon Apr 17 2017, 06:33PM
Tracking chemical composition as a function of length after electrophoresis sounds a bit like chromhotdography
Re: Why does the Resistance of a Hot Dog decrease as it heats up?
Enceladus, Tue Apr 18 2017, 01:38AM
Haha. You and your hot dogs.
Enceladus, Tue Apr 18 2017, 01:38AM
Haha. You and your hot dogs.
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