MIT Physics Demo -- Temperature Effect on Resistance

A light bulb is connected in series with a coil of very fine copper wire and a DC power supply. The voltage is adjusted so that the bulb glows dimly. When the coil is immersed in liquid nitrogen the resistance of the wire decreases causing the current to increase and the bulb to glow brightly.

See the original video and more on MIT TechTV here - http://techtv.mit.edu/videos/1689-temperature-effect-on-resistance

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Education

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• resistance
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• light
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• electromagnetism
• circuits
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• introductory
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• engineering

[animateclay]

Could you get a polarity reversal in basic circuits in this way? I've coated a penny and dime surface with sodium silicate with a piece of paper in-between to stop it from shorting out. Quartz dust was added to the silicate and it was let to dry. If I warm the penny with my fingers the voltage decreases slightly. The strange aspect is if I put this basic battery on an ice cube, the voltage goes down and polarity reverses. Then the negative volts build the longer it's on ice.

[killerdoug1]

@madogmgd actually quite the oposite, you are almost right but as a semicunducting material ( silicon) increases tempature it will actually conduct more. since it has a negative tempature coificient. ustabalising the q point and having less colntrool

[DartmouthAlum96]

V = IR. This video is VIRy interesting!

[PsalmsOfPlanets072]

@madogmgd mostly, its because the computer would overheat, the parts would expand and contract (when tuned off) which is never good on the structure of things, however the tempatures get very high and water(or the cooling soultion) is dense and cools faster than air

[licianinh]

Usually resistance depends on three things, the material, the length and the area. However, heat affects resistance, the higher the temperature the higher the resistance.

[madogmgd]

I get it thats why computers need liquid cooling for energy to pass through quickly.

Thus the computer cools when it receives enough energy to do commands.

[wildchildplasma]

Yes and we all use coolant to get the benefits but sir if you were working with crystal resonance then what sort of temperature modulation would be useful for such computable Apparatus .