Radar: A Silent Eye in the Sky
Today's society relies heavily on an invention taken for granted: radar.
Just about everybody uses radar, whether they realize it or not. Tens of
thousands of lives rely on the precision and speed of radar to guide their plane
through the skies unscathed. Others just use it when they turn on the morning
news to check the weather forecast.
While radar seems to be an important part of our everyday lives, it has
not been around for long. It was not put into effect until 1935, near World War
II. The British and the Americans both worked on radar, but they did not work
together to build a single system. They each developed their own systems at the
same time. In 1935, the first radar systems are installed in Great Britain,
called the Early Warning Detection system. In 1940, Great Britain and the
United States install radar aboard fighter planes, giving them an advantage in
plane-to-plane combat as well as air-to-ground attacks.
Radar works on a relatively simple theory. It's one that everybody has
experienced in their lifetime. Radar works much like an echo. In an echo, a
sound is sent out in all directions. When the sound waves find an object, such
as a cliff face, they will bounce back to the source of the echo. If you count
the number of seconds from when the sound was made to when the sound was heard,
you can figure out the distance the sound had to travel. The formula is:
(S/2) X 1100 = D (Half of the total time times 1100 feet
per second equals the distance from the origin to the reflection point)
Of course, radar is a much more complicated system than just somebody
shouting and listening for the echo. In fact, modern radar listens not only for
an echo, but where the echo comes from, what direction the object is moving, its
speed, and its distance. There are two types of modern radar: continuous wave
radar, and pulse radar.
Pulse radar works like an echo. The transmitter sends out short bursts
of radio waves. It then shuts off, and the receiver listens for the echoes.
Echoes from pulse radar can tell the distance and direction of the object
creating the echo. This is the most common form of radar, and it is the one
that is used the most in airports around the world today.
Continuous wave radar works on a different theory, the Doppler Theory.
The Doppler Theory works on the principle that when a radio wave of a set
time and what was going on at that moment. As it continues "A Sound of
... Association, if a the sound of a plane taking off is 1,000,000,000,000 times the threshold sound, and if the sound of a hand drill is 10,000,000,000 times the threshold sound, during which sound would you wear hearing protection?
4. Upgraded Early Warning Radars (UEWR): These radars systems detect targets near the horizon, early in the ballistic missi...
If you put your finger gently on a loudspeaker you will feel it vibrate - if it is playing a low note loudly you can see it moving. When it moves forwards, it compresses the air next to it, which raises its pressure. Some of this air flows outwards, compressing the next layer of air. The disturbance in the air spreads out as a travelling sound wave. Ultimately this sound wave causes a very tiny vibration in your eardrum - but that's another story.
...designed to simulate the effect of radar waves on different surfaces (CentannialOfFlight.gov). this was a marked advancement in stealth technology, because for the first time scientists realized that utilizing faceted surfaces, they could scatter almost all radar waves the hit an object away from the source thus making the said object invisible to radar detection, or nearly so. In 1977, this discovery was utilized in a new airframe for the F-117 Nighthawk. This new plane was designed entirely to avoid enemy electronic detection. With a revolutionary faceted design coated with RAM, or radar absorbent materials, the new plane was near-invisible to radar detection, and a new type of exhaust system lessened the heat trail coming from the plane’s engines, making for the first time an aircraft with a minimal infrared signature in addition to its minimal radar signature.
one simple reason for why it was introduced. It was not a new idea as
As a part of this longitudinal sound wave, the particles vibrate back and forth in a direction parallel to the direction of energy. Since the air molecules always return to their original position, they have no net displacement. When the vibrating molecules of air have to escape somewhere, this is where the sound hole comes into play. The air escapes through it and this is where the sound is projected. When all this occurs, it’s called the Helmholtz resonance (Wolfe).
Ultrasounds use the same concepts that allow sonar on boats to see the bottom of the o...
Sounds are produced by the vibrations of material objects, and travel as a result of
The Scholar: I think that's more a function of sound wave vibration than anything else.
Medical ultrasound mechanisms produce ultrasound waves and accord the imitated echoes. Brightness mode (B mode) is the frank mode that is normally used.[2] The B mode gives a two dimensional (2D) black and white picture that depends on the anatomical locale of the slice. The body can be imaged in disparate planes reliant on the locale of the probe. These slender slices are of less than 1 mm every single and can be sagittal, coronal, transverse, or oblique. Sound waves are emitted from piezoelectric crystals from the ultrasound transducer. Piezoelectric crystals are fabricated from physical that adjustments mechanical signals to mechanical vibrations and adjustments mechanical vibrations to mechanical signals.[2] As ultrasound waves bypass across assorted body tissues, they are imitated back to the transducer crafting an picture on the ultrasound screen.[3] Aural impedance is described as the confrontation for propagation of ultrasound waves. This varies according to the density of the physical ultrasound passes through. After the physical is extra solid, nex...
Sound is essentially a wave produced by a vibrating source. This compression and rarefaction of matter will transfer to the surrounding particles, for instance air molecules. Rhythmic variations in air pressure are therefore created which are detected by the ear and perceived as sound. The frequency of a sound wave is the number of these oscillations that passes through a given point each second. It is the compression of the medium particles that actually constitute a sound wave, and which classifies it as longitudinal. As opposed to transverse waves (eg. light waves), in which case the particles move perpendicular to the direction of the wave movement, the medium particles are moving in the same or opposite direction as the wave (Russell, D. A., 1998).
“One would think that so important a contribution to the world’s technology would be chronicled with great care at every step…This, unfortunately, is not the case, and for reasons quite understandable” (Page 14). Sometimes history can be hard to distinguish from truth and legend, the history of radar is no exception. Many contributions have been made to the development of radar over the years. For many years prior and during the Second World War, radar was considered a top-secret military tool. Once it was made public, people used the existing information about radar to come up with their own variations for different applications. As a result, the true origin of radar has become blurred within conflicting claims.
Acoustics is a science that deals with the study of sound. It is known to be one of the branches of physics; studying oscillations and sound waves from the lowest to high frequencies. Acoustics is known to be one of the oldest sciences, and dates back to ancient times as people had the need to understand the nature of speech and hearing. The main reason acoustics was discovered and is one of the oldest sciences is because of the need for the knowledge of the sounds of music and musical instruments. Pythagoras, an ancient mathematician, was the first person to ever find out that tone height corresponds to the length of the sting or tube. While Aristotle, Pythagoras apprentice at the time, helped more to explain that an echo is created as the sound reflection from obstacles.