How has the nature of waves been discovered over time?
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Leonardo Da Vinci (b 1452 d 1519) noticed that vibrating a wooden table on which dust lay created various shapes.
'I say then that when a table is struck in different places the dust that is upon it is reduced to various shapes of mounds and tiny hillocks. The dust descends from the hypotenuse of these hillocks, enters beneath their base and raises itself again around the axis of the point of the hillock.' 5
'I say then that when a table is struck in different places the dust that is upon it is reduced to various shapes of mounds and tiny hillocks. The dust descends from the hypotenuse of these hillocks, enters beneath their base and raises itself again around the axis of the point of the hillock.' 5
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Galileo Galilei (b 1564 d 1642) described scraping a brass plate with a chisel and noticed a 'long row of fine streaks, parallel and equidistant from one another,' 6 presumably caused by the brass filings dancing on the surface of the plate and finding safe haven in a series of parallel nodal striations.
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Robert Boyle
In 1660 Robert Boyle designs the vacuum and promptly uses it to prove that sound needs a medium
to travel through. He places an alarm clock in the airless vacuum and cannot hear it when it rings.
In 1660 Robert Boyle designs the vacuum and promptly uses it to prove that sound needs a medium
to travel through. He places an alarm clock in the airless vacuum and cannot hear it when it rings.
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Marin Mersenne
In the early 17th century, a Franciscan friar named Marin Mersenne (1588-1648) began the first recorded attempts to establish the speed of sound.To do this, Mersenne had a friend stand a known distance away and fire a gun. Mersenne then measured the amount of time between when he saw the flash from the gun and when he heard the sound of gunfire. Because he had no way to measure time precisely, Mersenne estimated the time in seconds by counting the number of times his heart beat between the flash and the sound.
Mersenne calculated that the speed of sound was approximately 1,480 feet per second (450 meters per second).
In the early 17th century, a Franciscan friar named Marin Mersenne (1588-1648) began the first recorded attempts to establish the speed of sound.To do this, Mersenne had a friend stand a known distance away and fire a gun. Mersenne then measured the amount of time between when he saw the flash from the gun and when he heard the sound of gunfire. Because he had no way to measure time precisely, Mersenne estimated the time in seconds by counting the number of times his heart beat between the flash and the sound.
Mersenne calculated that the speed of sound was approximately 1,480 feet per second (450 meters per second).
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Heinrich Hertz
Heinrich Hertz was the first to send and receive radio waves. James Clerk Maxwell had mathematically predicted their existence in 1864. Between 1885 and 1889, as a professor of physics at Karlsruhe Polytechnic, he produced electromagnetic waves in the laboratory and measured their wavelength and velocity. He showed that the nature of their reflection and refraction was the same as those of light, confirming that light waves are electromagnetic radiation obeying the Maxwell equations.
Heinrich Hertz was the first to send and receive radio waves. James Clerk Maxwell had mathematically predicted their existence in 1864. Between 1885 and 1889, as a professor of physics at Karlsruhe Polytechnic, he produced electromagnetic waves in the laboratory and measured their wavelength and velocity. He showed that the nature of their reflection and refraction was the same as those of light, confirming that light waves are electromagnetic radiation obeying the Maxwell equations.
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This is the apparatus Hertz used to transmit radio waves. He proved a spark jumping from one electrode to another will release electromagnetic radiation. These waves can subsequently be picked up or "received" by an antennae.
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Jeffrey Spicolli
In 1982. Actor Sean Penn plays Jeff Spicolli in the critically acclaimed "Fast Times at Ridgemont High" in which he catches some "gnarly waves."
In 1982. Actor Sean Penn plays Jeff Spicolli in the critically acclaimed "Fast Times at Ridgemont High" in which he catches some "gnarly waves."