Gifts for a 25th Anniversary. 25th anniversary gifts should express your love and adoration in a simply elegant fashion. The 25th wedding anniversary is commemorated traditionally with gifts of silver, and we have a variety of options that make for a perfect silver wedding anniversary gift. Peruse silver lockets, delightful champagne glasses, commitment bands, and more for a gift that perfectly presents the 25-year anniversary motif.
The released energy travels as shock waves, called seismic waves, which may be felt and measured. The study of seismic waves is known as seismology, a word derived from a Greek word meaning to shake.. Seismographs are the instruments which record earthquakes. Scientists use these instruments as their principal tool to study seismic waves. They are very sensitive instruments that can detect, measure and record ground vibrations and their intensities during an earthquake.
seismograph A seismograph, or seismometer, is an instrument used to detect and record earthquakes. Generally, it consists of a mass attached to a fixed base. During an earthquake, the base moves and the mass does not. The motion of the base with respect to the mass is commonly transformed into an electrical voltage. The electrical voltage is recorded on paper, magnetic tape, or another recording medium.