to investigate the variation of the resistance of a metallic conductor with temperature

Question 1

describe with the aid of a diagram, how the student measured the temperature of the wire.

Answer 1

place the wire and a sensitive thermometer into a large test tube filled with glycerol. place this test tube in a beaker of cold water and allow the temperature as recorded by the thermometer to give a steady reading. turn on the heat source and allow an increase in temp of about 5C, then remove the heat source, wait for the thermometer’s temperature to stop rising and record the temperature

Question 2

how did the student vary the temperature of the wire?

Answer 2

using a water bath and heat source such as a hot plate

Question 3

why was glycerol used?

Answer 3

glycerol is a better heat conductor than water- it maintains better thermal contact with the wire- water would form small bubbles of gas at the wire. glycerol also has a lower specific heat capacity

Question 4

draw a suitable graph to show the relationship between the resistance of the metal conductor and its temperature

Answer 4

resistance vs. temperature

Question 5

what does your graph tell you about the relationship between the resistance of a metallic conductor and its temperature?

Answer 5

the graph is a straight line graph that doesn’t go through the origin- this shows that the resistance of a metallic conductor increases linearly as the temperature increases.

Question 6

what errors should be avoided?

Answer 6

heat the water slowly to avoid overheating the glycerol.
measure the resistance of the ohmmeter wires
parallax error when reading the thermometer