Running the gravimeter
Clamp the gravimeter in a retort stand as
vertically as possible. Leave an empty space
of around 10 cm between the bottom of the
pipe and the padded landing site. Run the
program ‘Gravimeter.exe’ and follow the on-line
instructions. Hold the magnet above the open
top of the pipe, click the start button and half
a second later release the magnet. The program
will record the voltage signal generated by the
magnetic field lines cutting through the turns of
the coils, and display the signal as a graph. Use
the large knob on the left-hand side to increase
the gain if necessary. Figure 7 shows the starting
window of the gravimeter program with a typical
recorded waveform. Notice the gradual increase
in amplitude as well as the shortening of the
‘period’ in the time axis.