Archimedes Challenge – Seismograph

History

The first seismograph was invented in China by Chinese Philosopher and polymath Zhang (Cheng) Heng in 132CE. This machine was invented because the Chinese culture believed that earthquakes were a message sent from heaven, and it was important for the leaders to be alerted and notify their kingdom of any earthquakes. In a more modern way the invention was made to alert observers and to notify people. Luigi Palmieri, Thomas Lomar Gray, James Alfred Ewing worked as a team to help John Milne invent the more modern day seismograph. Milne designed the first reliable seismograph in 1880 and shortly after travelled to Asia to set up many stations with seismographs to calculate their seismic waves through Asia.

Physics Involved

This is a picture of a modern day seismograph. It measures three different types of data, LHT which measures perpendicular with earths displacement, LHR which measures the wave radial or in its direction of it and LHZ which measures the wave vertical to its direction. Unlike our example of a seismograph, the pendulum or pen isn’t the object shaking, inertia actually keeps it in its place. The movement beneath the pen or pendulum cause the line to go on the paper. If the voltage gets bigger the characteristics of the type of dimensions gets bigger, and if the voltage gets smaller the characteristics of the dimensions gets smaller. The eqation for this and the graph is ΔV=kΔL. A seismometer isn’t actually doing any work, because of this you cant calculate its efficiency because no work is provided.

Building Process

Materials: Shoe box, elastic bands, sharpie, paper roll, pencil, hot glue gun

To start the process of our machine we needed to create a plan. Here we have all the materials and a diagram of how we wanted out seismograph to look like.

2. We made a elastic chain by linking multiple elastics together to act as the spring and this would hold the pendulum.

3. We created a stand for the paper roll, so we didn’t need someone holding the roll at all times. This acted as the rotating drum. The paper will be able to slide through the cut out slits on the bottom of the box.

4. Then we tested out the machine to see if it functioned well and that there were no problem. One problem we faced is that the pen needed more weight on it, but when we added weight it was harder for it to move and get accurate data.

Test Video