4.3 On the construction of the moveable teaching seismograph
Here we see a basic diagram of our teaching seismograph, as it was built by our young scientists Bernd, Sebastian and Thomas. The diagram does not show the side struts.
Adjusting the supporting screws on the outer frame easily changes the period of oscillation of our pendulum. As the instrument is placed on the ground one is relatively independent of the movements of the building when the seismograph is placed upon the basement-floor of the building.
The following photograph shows the teaching seismograph from the top:
The registration of the pendulum's oscillation is electronic. We attach a coil to the pendulum, which has about 40,000 coils of varnished wire (diameter 0.16mm). On one side this coil is placed within a strong permanent magnet. In the yoke both permanent magnet-blocks create a magnetic field of about 0.8 Tesla (we will be happy to forward information on technical details to anyone who sends us an email).