Sismograph

A sismograph is an instrument used to detect and record ground vibrations caused by earthquakes or other seismic sources. It consists of a sensor that remains anchored to the ground and a pen connected to a mass that can move freely. When the ground shakes, the sensor moves, but the pen, due to inertia, stays relatively stationary. This relative motion causes the pen to mark a continuous record, called a seismogram, on paper or digital media. The seismogram reveals the timing, strength, and frequency of seismic waves, helping scientists analyze and understand earthquakes.