Answer 1:
To test the conductivity of different metals,
you will need:
1. Samples of each of the metals you want
to test. Make sure all the samples have the same
dimensions (crosssectional area and length).
The easiest way to do this is to get wires of
the same gauge (diameter) made out of each of
the materials that you want to test, and cut
them to the same length.
2. A digital multimeter. This is an
important and handy tool for many electrical
tasks.
3. A ruler.
Now that you have all of the materials:
1. use the multimeter to measure the
resistance from one end of the wire to the
other. Do this by attaching the one end of the
wire to one of the leads of the multimeter, and
the other end of the wire to the other lead on
the multimeter. Then, with the multimeter in the
resistance measuring mode, it should displace
the resistance of the wire (measured in ohms
denoted by the symbol ?).
2. Use the ruler to measure the length of
the wire (use SI units such as centimeters (cm)
and convert to meters (m) by dividing by
100).
Now, the conductivity of the metal (per unit
length) is given by 1/(resistance*length)
which is in units of 1/( ?*m) which is the
same as S/m where S is the SI unit of
conductivity called Siemens.
Wikipedia has a nice table of conductivity of
several metals. Here is the data for some of the
metals you mentioned so that you can check you
results and calculate the percent error for you
experiment [%error=100%* (actual value
experimental value)/actual value]
Copper 5.96×10^{7} S/m
Aluminium 3.5×10^{7} S/m
The conductivity of metals is related to the
charge carrier density (such as how many
electrons are free to move about the metal and
flow in response to an electric field) as well
as the charge carrier mobility (how freely the
charge carriers can flow through the metal).
Different metals have different charge carrier
densities as well as different charge carrier
mobilities which results in different
conductivities. Many factors affect the charge
carrier density and mobility including things
such as the chemistry of the material (such as
what atoms are in the materials and at what
ratio) as well as the structure of the material
(crystalline, different crystal structures, as
well as other ordered or disordered
structures).
Many fields work with metals and their electric
properties. One such field is Materials Science.
I am a graduate student in the materials
department, but there are many areas of material
science, and not all of them work with
metals.
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