This document discusses various types of infrasound, which are sounds lower than 20 Hz that can have physical effects on humans and animals. It describes infrasound produced by natural phenomena like volcanoes, earthquakes, and whales communicating over long distances. It also discusses infrasound generated by man-made sources like weapons, vehicles, and electrical equipment. The document notes how infrasound was intentionally used by Nazi propagandists and was accidentally produced at a Disney theater, disorienting the crowd for days.
Infrasound refers to sound waves below 20 Hz that cannot be heard by humans but can be felt. It can produce anxiety, sorrow, or chills in people and carries far distances with little loss of strength. Examples of natural infrasound sources include volcanoes, earthquakes, and ocean waves. Ultrasound refers to sound waves above 20 kHz that cannot be heard but can be used in medical imaging devices to produce images of internal tissues and structures. Ultrasound works by transmitting sound waves that bounce off internal tissues and are received back by the transducer to form an image. It is used for fetal imaging, cardiac imaging, and assessing blood flow through Doppler techniques.
5. Инфразвук в природата Известно е, че китовете, слоновете, носорозите, жирафите, антилопите, окапи и алигаторите използват инфразвук, за да предават съобщения на различни разстояния, например при китовете на много километри. Животни които чуват инфразвука . ν <20Hz Хипопотам Носорог Жираф Алигатор Тигър Слон
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9. Сеизмични вълни уплътнение разреждане посока на разпространение на вълната направление на трептене направление на трептене покой напрежение освобождаване на напрежението граница на еластичност
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