23 November 2013
Resistance dependence on a temperature
Research Question: How does the temperature of wire affect the resistance?
Hypothesis: In such a conductor as Nico, with the temperature increase - resistance increases too.
Explanation of hypothesis:
As far as we know, Nico is not superconductor, it is a simple conductor. To prove that when temperature of a conductor increases, its resistance increases too, we can take such scientific explanation:
The low temperature resistivity depends on the concentration of lattice defects, such as dislocations, grain boundaries, vacancies, and interstitial atoms. Consequently, it is lower in annealed, large crystal metal samples, and higher in alloys and work hardened metals. You might think that at higher temperatures the electrons would have more energy to be able to move through the material, so perhaps it is rather surprising that resistivity increases (and conductivity therefore decreases) as temperature increases. The reason for this is that as temperature increases, the electrons are scattered more frequently by lattice vibrations, or phonons, which causes the resistivity to increase (Factors affecting electrical conduction).
Finally, what happens to the mobility? Temperature will decrease the drift velocity because as the temperature increases, the atomic vibrations will increase, which will cause more collisions of the electrons with the crystal lattice. Hence the drift velocity will decrease (Wendy Kaufmyn).
· Hot plate
· Multi meter
· Resistance meter
· Variable resistor
· High temperature thermometer
· Vegetable oil
· Nico resistance wire
Variables (“Fair testing”):
During the research we manipulate with temperature of the wire to find out, whether the resistance changes, according to our hypothesis.
Type of variable|Variable|How the Variable is Manipulated, Measured or Controlled|