The loudest sound the Earth has ever produced
The loudest natural sounds on Earth are caused by erupting volcanoes. The 1883 eruption on Krakatoa may be the loudest noise the Earth has ever made. When Krakatoa volcano erupted, a barometer at the Batavia gasworks (160 km away from Krakatoa) registered a spike in pressure of over 8.5 kPa, converting to over 172 decibels (dB) of sound pressure.
The noisiest city in the world
According to research done by City Quiet, the top three noisiest cities in the world are Mumbai (India), Kolkata (India) and Cairo (Egypt). Thanks to the severe city traffic, ever-continuing construction and serious overpopulation, Mumbai is considered the noisiest city in the world with sound levels that can exceed 100 decibels. The loudest city in the Europe is Madrid (Spain), while New York is the only United States city on the top 10 noisiest cities in the world.
The loudest animal on Earth
Although the call of a blue whale reaches 188 decibels, which is even louder than jet engine or grenade explosion, the loudest animal on Earth is the sperm whale whose communicative clicks have been measured at 230 dB.
The main source of noise in the urban environments
According to the European Environment Agency (EEA) briefing ‘Managing exposure to noise in Europe’, the transport sector is a major cause of the noise pollution. Road traffic is the dominant noise source affecting approximately 100 million people in the 33 member countries of the EEA. Of these, 32 million are exposed to very high noise levels (above 65 dB). Railway is the second largest source, with 19 million people exposed to noise levels above the EU’s threshold of 55 decibels. The aircraft (close to major airports) is the third main source, with more than 4.1 million people exposed, followed by industrial noise within urban areas, with 1.0 million people exposed.
construction and serious overpopulation, Mumbai is considered the noisiest city in the world with sound levels that can exceed 100 decibels. The loudest city in the Europe is Madrid (Spain), while New York is the only United States city on the top 10 noisiest cities in the world.
The loudest single-event in history
The Tunguska event was a massive explosion that occurred near the Podkamennaya Tunguska River at 7:40 AM on June 30, 1908. The explosion was most likely caused by the air burst of a large meteoroid 5-10 kilometers above the earth surface. The explosion was strong enough to destroy an entire metropolitan area, flattening an estimated 80 million trees over an area of 2150 square km. It’s estimated that the Tunguska event reached 300-315 dB, which can be measured with the impact of a 1000-Mega-ton bomb. This is often considered to be the loudest single-event in history.
been measured at 230 dB.
The industry with the loudest work environment
In 2015, the Centers for Disease Control and Prevention found that mining was the industry with the loudest work environment, followed by manufacturing and construction. About 1 in 8 of the workers in these and similar industries had hearing loss caused by their work environment.
Top 5 loudest sounds produced by human activities
- Fireworks – at the bursting point fireworks reach a staggering 145-150 decibel levels
- Gunfire – the gunshot can reach up to 145-155 dB
- NHRA dragster – sitting next to a dragster as it fires up its engines and screams down the raceway can be more than just loud – at the 155-160 decibel range it will severely to permanently damage your hearing
- Space Shuttle Launch – when the rockets fire, it is wise that you stand at least one kilometer away lest you get inundated by 165-170 decibels of painful sound
- 1-Ton TNT Bomb – 75 meters away from the impact, the resulting explosion from a 1 ton bomb creates a decibel count of 210
Part of the ear the most vulnerable to noise
Noise can damage hair cells, membranes, nerves, or other parts of the ear, causing temporary or permanent hearing loss. Loud noise is particularly harmful to tiny hair cells (types of receptors within the inner ear). These cells are a sort of microphones and without them hearing would be impossible. It is their small size what makes them so vulnerable. Repeated exposure to loud noises gradually destroys these tiny cells.
The speed of sound
The speed of sound depends strongly on temperature as well as the medium through which a sound wave is propagating. Sound waves travel faster in solids than in liquids, and faster in liquids than in gasses. At 20 °C, the speed of sound in air is about 343 m/s. In water, sound travels almost 4.3 times faster (at 1481 m/s), while through the diamond speed of sound is about 12000 m/s.
Propagation of sound waves in different mediums
Sound waves are travelling vibrations of particles in media such as air, fluids or metal. Although Hollywood directors love using sound effects in outer space for added drama, in the vacuum of space, there are no particles to vibrate, so sound cannot travel through this medium.
