A parabola is nothing but a U-shaped plane curve. Any point on the parabola is equidistant from a fixed point called the focus and a fixed straight line known as the directrix.
arabolas can, in fact, be seen everywhere, in nature as well as manmade items. Consider a fountain. The water shot into the air by the fountain falls back in a parabolic path.
A ball thrown into the air also follows a parabolic path. Galileo had demonstrated this. Also, anyone who rides a roller coaster will be familiar with the rise and fall created by the track’s parabolas.
Parabolas in Architecture and Engineering
Even architecture and engineering projects reveal the use of parabolas. Parabolic shapes can be seen in The Parabola, a structure in London built in 1962 that boasts a copper roof with parabolic and hyperbolic lines.
The famous Golden Gate Bridge in San Francisco, California, has parabolas on each side of its side spans or towers.
Using Parabolic Reflectors to Focus Light
Parabolas are also commonly used when light needs to be focused. Over the centuries, lighthouses underwent many variations and improvements to the light they could emit. Flat surfaces scattered light too much to be useful to mariners.
Spherical reflectors increased brightness, but could not give a powerful beam. But using a parabola-shaped reflector helped focus light into a beam that could be seen for long distances. The first known parabolic lighthouse reflectors formed the basis of a lighthouse in Sweden in 1738.
Many different versions of parabolic reflectors would be implemented over time, with the goal of reducing wasted light and improving the surface of the parabola.
Eventually, glass parabolic reflectors became preferable, and when electric lights arrived, the combination proved to be an efficient way of providing a lighthouse beam.
The same process applies to headlights. Sealed-beam glass automobile headlights from the 1940s to the 1980s used parabolic reflectors and glass lenses to concentrate beams of light from bulbs, aiding driving visibility.
Later, more efficient plastic headlights could be shaped in such a way that a lens was not required. These plastic reflectors are commonly used in headlights today.
Using parabolic reflectors to concentrate light now aids the solar power industry. Flat photovoltaic systems absorb the sun’s light and free electrons, but do not concentrate it. A curved photovoltaic mirror, however, can concentrate solar power much more efficiently.
Huge curved, mirrors comprise the enormous Gila Bend parabolic trough solar facility, Solana. The sunlight is focused by the parabolic mirror shape in such a way that it generates very high heat.
This heats tubes of synthetic oil at the trough of each mirror, which can then either generate steam for power, or be stored in massive tanks of molten salt to store energy for later.
The parabolic shape of these mirrors allows more energy to be stored and made, making the process more efficient.
Parabolas in Spaceflight
The shimmering, stretched arc of a rocket launch gives perhaps the most striking example of a parabola. When a rocket, or other ballistic object, is launched, it follows a parabolic path, or trajectory.
This parabolic trajectory has been used in spaceflight for decades. In fact, airplanes can create zero- and high-gravity environments by flying in parabolas. Special airplanes fly at a steep angle, giving a higher-gravity experience, and then drop into what is called freefall, giving a zero-gravity experience.
Experimental test pilot Chuck Yeager went through such tests. This has provided tremendous research for both human pilots and their tolerance of spaceflight and flying in various gravities, to performing experiments requiring low or zero gravity.
Such parabolic flights save money by not having to perform every experiment in space itself.
Other Uses for Parabolas
Consider the satellite dish. These structures have a parabolic shape, allowing the reflection and focus of radio waves.
In much the same way that light can be bent, electrons can be as well. It has been discovered that beams of electrons can be sent through holographic film and curved around barriers in a parabolic fashion.
These are called Airy beams, and they do not grow faint and diffract. These beams may prove useful in imaging.
From spaceflight and car headlights to bridges and amusement parks, parabolas can be seen everywhere. Not only is a parabola an elegant geometric shape, its functional capability aids humanity in many ways.
Examples of Parabola
#1. Kicking the ball
When you kick a soccer ball, it arcs up into the air and comes down again, following the path of a parabola.
#2. Shooting an arrow
When you shoot an arrow, it arcs up into the air and comes down again, following the path of a parabola.
#3. Throwing a stone
When you throw a stone, it arcs up into the air and comes down again, following the path of a parabola.
#4. Satellite Dishes
A satellite dish is a type of parabolic antenna that receives or transmits information by radio waves to or from a communication satellite. 16 Parabola Examples in Real Life
#5. Parabolic trough
Parabolic troughs are solar thermal collectors that are curved in three dimensions as a parabola, lined with polished metal mirrors. These are many used to concentrate the sun’s rays to make a hot spot.
#6. Spotlight reflectors
Spotlights have parabolic reflectors that are used to project a bright beam of light onto a performance space.
#7. Flashlight
A flashlight or torch has a parabolic reflector that gives a variable-focus effect from a wide floodlight to a narrow beam.
#8. Parabolic microphone
A parabolic microphone has a parabolic reflector that collects and focuses sound waves onto a transducer.
#9. Automobile headlight
Automobile headlamps have parabolic reflectors that collect and focus the beam of light to illuminate the road ahead.
#10. Ballistic missile
A Ballistic missile delivers warheads on a target by using projectile motion. The trajectory of these missiles makes a parabolic path.
#11. Jump of a Dolphin
The jump of a dolphin is known as porpoising. According to some research, dolphins use their jump as a method of communication. If you look at a dolphin’s porpoising, you will observe that they trace a parabolic path while performing the jump.
#12. Camera
Many cameras use an assembly of parabolic mirrors to take wide-angle shots.
#13. IR Spectrometer
Some gated spectrometers use a pair of 90-degree off-axis parabolic mirrors to relay the light from an entrance slit to an output IR recording camera.
#14. Parabolic dunes
Parabolic dunes are formed when strong winds erode a section of the vegetated sand (commonly referred to as a blowout). Parabolic dunes are common in the sand sheet southwest of the main dune field.
#15. Reflecting telescopes
Some reflecting telescopes use parabolic mirrors to reduce spherical aberration with no chromatic aberration.
#16. Parabolic Wifi antenna
A parabolic wifi device uses a parabolic antenna that is backed with a parabolic reflector that directs waves, in this case, wifi waves, to the antenna, enhancing the wifi signal.