Ultrasound uses high frequency sound waves to image internal structures. A transducer converts electrical pulses into ultrasound pulses and reflected sound waves back into electrical signals. Tissues reflect sound differently allowing visualization. Higher frequencies improve resolution but reduce penetration. Ultrasound has various medical uses like imaging fetuses, organs and detecting abnormalities by interpreting echo patterns. It provides real-time images without radiation unlike other modalities.
This document provides an overview of sinus surgery and CT scan imaging for sinus procedures. It discusses:
1. CT scan is the preferred imaging modality for sinus surgery as it can accurately demonstrate bone anatomy and the extent of disease.
2. When reading CT scans, it is important to view the coronal, axial, and sagittal planes and identify key anatomical structures like the nasal septum and skull base.
3. Contrast can help identify complications like abscesses or tumors. Systematic evaluation of anatomy, variations, pathology and risk to nearby structures is important.
Fluoroscopic techniques and anatomy of pharynx and esophagus finalabduljelil nejmu
This document discusses fluoroscopic techniques and anatomy of the pharynx and esophagus. It outlines contrast media used, indications for fluoroscopic studies, patient positioning, and normal anatomy and function of the pharynx and esophagus. The pharynx and esophagus are evaluated using barium and iodinated contrast agents under fluoroscopy to assess for abnormalities in swallowing, motility, and anatomy.
This document discusses the importance of CT scans for identifying anatomy, operative planning, risk assessment, and informed consent in ENT procedures. It outlines key structures visible on axial, coronal, and sagittal CT scan planes of the temporal bone including the semicircular canals, vestibular aqueduct, internal auditory canal, ossicles, cochlea, facial nerve, and direction of scan slices. The document is intended to educate on interpreting temporal bone CT scans for ENT procedures.
This document discusses Doppler ultrasound principles and techniques. It covers topics like Doppler signal processing including transmitters, amplifiers, mixers and filters. It describes how Doppler is used to measure blood flow velocity and direction. It also discusses optimization of Doppler settings like range gate size, gain, filter and steering angle to improve flow detection and spectral waveform analysis. Color Doppler imaging principles are also covered like mapping Doppler shifts to a color map and factors affecting color box placement and pulse repetition frequency.
This document discusses ultrasound physics and principles. It covers the characteristics of sound waves including their need for a medium, compression and rarefaction, and propagation. It describes ultrasound wave properties like range, velocity in different media, and how velocity relates to compressibility, density, and intensity. Transducers are discussed including their piezoelectric crystal, electrode, and backing block components. Modes of ultrasound like continuous wave and pulse wave are summarized. Key interactions of ultrasound with matter like reflection, refraction, and absorption are covered. Principles of Doppler ultrasound for blood flow measurement are outlined.
This document discusses the history of stapes surgery and recent concepts. It covers the key individuals who advanced the field from the 1700s onwards, including the development of stapedectomy and stapedotomy procedures. It then describes different types of otosclerosis, techniques for stapes surgery including laser vs drill fenestration and prosthesis options. Potential complications of surgery are outlined such as perilymphatic gusher, sensorineural hearing loss and vertigo. Outcomes of stapedectomy versus stapedotomy are compared.
Ultrasound uses high frequency sound waves to image internal structures. A transducer converts electrical pulses into ultrasound pulses and reflected sound waves back into electrical signals. Tissues reflect sound differently allowing visualization. Higher frequencies improve resolution but reduce penetration. Ultrasound has various medical uses like imaging fetuses, organs and detecting abnormalities by interpreting echo patterns. It provides real-time images without radiation unlike other modalities.
This document provides an overview of sinus surgery and CT scan imaging for sinus procedures. It discusses:
1. CT scan is the preferred imaging modality for sinus surgery as it can accurately demonstrate bone anatomy and the extent of disease.
2. When reading CT scans, it is important to view the coronal, axial, and sagittal planes and identify key anatomical structures like the nasal septum and skull base.
3. Contrast can help identify complications like abscesses or tumors. Systematic evaluation of anatomy, variations, pathology and risk to nearby structures is important.
Fluoroscopic techniques and anatomy of pharynx and esophagus finalabduljelil nejmu
This document discusses fluoroscopic techniques and anatomy of the pharynx and esophagus. It outlines contrast media used, indications for fluoroscopic studies, patient positioning, and normal anatomy and function of the pharynx and esophagus. The pharynx and esophagus are evaluated using barium and iodinated contrast agents under fluoroscopy to assess for abnormalities in swallowing, motility, and anatomy.
This document discusses the importance of CT scans for identifying anatomy, operative planning, risk assessment, and informed consent in ENT procedures. It outlines key structures visible on axial, coronal, and sagittal CT scan planes of the temporal bone including the semicircular canals, vestibular aqueduct, internal auditory canal, ossicles, cochlea, facial nerve, and direction of scan slices. The document is intended to educate on interpreting temporal bone CT scans for ENT procedures.
This document discusses Doppler ultrasound principles and techniques. It covers topics like Doppler signal processing including transmitters, amplifiers, mixers and filters. It describes how Doppler is used to measure blood flow velocity and direction. It also discusses optimization of Doppler settings like range gate size, gain, filter and steering angle to improve flow detection and spectral waveform analysis. Color Doppler imaging principles are also covered like mapping Doppler shifts to a color map and factors affecting color box placement and pulse repetition frequency.
This document discusses ultrasound physics and principles. It covers the characteristics of sound waves including their need for a medium, compression and rarefaction, and propagation. It describes ultrasound wave properties like range, velocity in different media, and how velocity relates to compressibility, density, and intensity. Transducers are discussed including their piezoelectric crystal, electrode, and backing block components. Modes of ultrasound like continuous wave and pulse wave are summarized. Key interactions of ultrasound with matter like reflection, refraction, and absorption are covered. Principles of Doppler ultrasound for blood flow measurement are outlined.
This document discusses the history of stapes surgery and recent concepts. It covers the key individuals who advanced the field from the 1700s onwards, including the development of stapedectomy and stapedotomy procedures. It then describes different types of otosclerosis, techniques for stapes surgery including laser vs drill fenestration and prosthesis options. Potential complications of surgery are outlined such as perilymphatic gusher, sensorineural hearing loss and vertigo. Outcomes of stapedectomy versus stapedotomy are compared.
Ultrasound uses high frequency sound waves that are transmitted into the body. The echoes that bounce back are used to form images of tissues and organs. Higher frequencies provide better resolution but penetrate less deeply. Ultrasound is used for diagnostic medical imaging and to guide procedures by providing real-time visualization of internal structures. It has advantages of being noninvasive, having no known health effects, and being relatively inexpensive compared to other imaging modalities.
Anatomy of external and middle ear by dr. faisal rahmanFaisalRahman153
This includes anatomy of external and middle ear with their clinical co relations. Embryology is also discussed here. Pinna, External auditory canal, Tympanic membrane, Middle ear Cleft, Mastoid and Auditory tube topics are included.
1. Ultrasound uses high frequency sound waves and their echoes to produce medical images of the inside of the body. 2. The ultrasound machine transmits sound pulses into the body using a probe, which detects the echoes reflected back from tissues and organs. 3. By measuring the time it takes for the echoes to return, the machine can calculate distances to internal structures and display a 2D image on the screen based on the intensities of the echoes.
otosclerosis....
stapedectomy vs stapedotomy
complication of otosclerotic surgery
management of otosclerotic surgery complications
techniques
latest trends
Ultrasound Machine-A Revolution In Medical ImagingRAVI KANT
What is medical imaging?
Why ultrasound imaging is required?
History of ultrasound
What is ultrasound
Physical definition
Medical definition
Ultrasound production
The Returning echo
Doppler effect
What is Doppler ultrasound
Principles of instrumentation in ultrasonography
Transmitter and receiver circuits of ultrasound
Mechanical assembly of ultrasound machine
Manufacturing companies of USG
Sonoscape S40 color Doppler ultrasound system
Clinical applications of ultrasound
Future of ultraso
This document provides an overview of the history and physics of ultrasound machines. It discusses how ultrasound works, including how sound waves are produced and received, how images are formed, and factors that affect image quality. The key components of an ultrasound machine are described, including the transducer probe, central processing unit, display, and storage devices. Different ultrasound imaging modes like A-mode, B-mode, and M-mode are introduced along with common medical applications of ultrasound imaging.
The document provides an overview of ultrasound physics and optimization for ultrasound-guided regional anesthesia. It discusses the basics of sound waves and how they interact with tissues. Key points include: the piezoelectric effect which converts mechanical energy to electrical energy; acoustic impedance and how it affects reflection and refraction; and factors that influence image quality such as transducer selection, gain, depth, and angle of insonation. Common artifacts are also reviewed. Proper ergonomics, scanning techniques, and safety strategies are emphasized for obtaining optimized ultrasound images.
This document provides an overview of ultrasound physics basics. It discusses how ultrasound uses sound waves between 10-20 MHz to generate images. Sound waves are longitudinal waves that travel through materials at different speeds depending on compressibility and density. Ultrasound imaging works by transmitting pulses into the body and receiving echoes, with transducers converting between electrical and sound signals. Factors like frequency, beam characteristics, and tissue interactions impact the resulting images and potential artifacts. Understanding ultrasound physics principles is important for optimizing scans and interpreting images.
The document discusses bone conduction hearing devices (BCHDs) and their components, functioning, advantages over conventional hearing aids, and surgical classifications. It provides details on the normal routes of bone conduction, components of acoustic and implantable hearing devices, pathophysiology of cochlear deafness addressed by implantable devices, and terminology used. It also outlines clinical indications and criteria for BCHDs as well as some limitations.
a detailed description of middle ear anatomy including embyology, development, temporal bone anatomy, anatomical variations, ossicles, mucosal folds, fissures, tympanic membrane, chorda tympani, nerve supply, various walls of middle ear, tegmen, windows
in short- everything about middle ear anatomy in detail
The document discusses hemoptysis, defined as bleeding from the lungs or bronchial tubes. It describes the dual arterial blood supply to the lungs from the pulmonary and bronchial arteries. Conditions that reduce pulmonary arterial flow can increase bronchial artery contribution, making those vessels prone to rupture and bleeding. A comprehensive evaluation of hemoptysis includes history, physical exam, labs, chest imaging including radiography and CT, and bronchoscopy. CT is particularly useful for evaluating underlying lung abnormalities and identifying abnormal bronchial vessels to guide treatment.
This document provides an overview of ultrasound physics principles:
1. It describes how ultrasound works by using a transducer to emit pulses that reflect off tissues and are received back to form an image, and how tissue properties like density and velocity affect reflection and transmission.
2. It explains key ultrasound concepts such as wavelength, frequency, amplitude, acoustic impedance, and gain which determine image quality, as well as Doppler effects which provide blood flow information.
3. The primary components of an ultrasound system are described as the transducer, which emits and receives sound, and the imaging instrument which processes the returning echoes to display an image.
Ultrasound uses high frequency sound waves to image internal structures. It works by sending sound waves into the body which bounce off tissues and organs, creating echoes. The echoes are detected and used to produce images on screen. Key physics principles include velocity, wavelength, frequency and amplitude of the sound waves. How the waves interact with different tissues through reflection, transmission, scattering and attenuation impacts image quality. Resolution, beamforming and processing power determine how well an ultrasound system can distinguish between tissues. Doppler and colour Doppler utilize the Doppler effect to evaluate blood flow velocity and direction to provide functional information.
Vocal nodules are benign, bilateral growths on the vocal cords caused by overuse or misuse of the voice. They are usually treated with voice therapy and rest, and may require surgery if not improved after 3-6 months. Vocal polyps are also benign growths but are usually unilateral and caused by vocal trauma or irritants like smoking. They are typically treated with excision during microlaryngoscopy. Reinke's edema is a bilateral swelling of the vocal cords caused by irritants like smoking, and is treated by removing the fluid or tissue via stripping under microlaryngoscopy along with voice therapy.
The document provides an overview of interpreting chest x-rays, including:
1. It describes the radiologic signs of lobar and segmental lung collapse including displacement of fissures, volume loss, hilar elevation, and crowding of vessels and bronchi.
2. Specific features of collapse in different lung lobes are outlined, such as the triangular density seen in right middle lobe collapse on lateral view.
3. Degree of collapse can affect radiologic findings from subtle increased opacity to complete loss of fissure lines. Additional signs like the superior triangle sign may help with diagnosis.
4. Causes of an opacified hemithorax are discussed, highlighting how mediastinal shift
The document summarizes key aspects of sound physiology and hearing. It describes how sound is produced through vibration, propagated through media, and detected by the ear. It explains the functions of the outer, middle, and inner ear in transmitting sound vibrations and converting them into neural signals. The cochlea analyzes sounds by frequency using a traveling wave mechanism and hair cells that transduce vibrations into electrical signals sent to the brain via the auditory nerve.
Computerized tomography (CT) uses X-rays and digital image processing to generate cross-sectional images of the body. Godfrey Hounsfield invented the first commercially viable CT scanner in 1972. CT scans provide more detailed images than traditional X-rays by using multiple angles to reconstruct cross-sectional slices of the body. Modern CT scanners can obtain these slices quickly, in under one second, allowing imaging of moving structures like the heart.
This document provides information on various endoscopic procedures used in diagnosing and treating conditions of the nasal cavity, throat, esophagus, and lungs. It describes the indications, contraindications, procedures, and potential complications of nasal endoscopy, videolaryngoscopy, esophagoscopy, bronchoscopy, and nasopharyngoscopy/rigid pharyngolaryngoscopy. Key details covered include the diagnostic and therapeutic uses of each scope, as well as size recommendations for pediatric versus adult procedures.
This document provides information on various laryngeal pathologies that can be diagnosed using imaging techniques like CT and MRI. It discusses laryngeal cysts, laryngoceles, thyroglossal cysts, laryngotracheitis, epiglottitis, Wegener's granulomatosis, laryngeal stenosis, vascular malformations, vocal cord paralysis, laryngeal trauma, squamous cell carcinoma, supraglottic carcinoma, glottic carcinoma, transglottic carcinoma, subglottic carcinoma, atypical squamous cell carcinomas, hemangiomas and more. Imaging findings that help diagnose and characterize these conditions are also described.
Ultrasound uses high frequency sound waves that are transmitted into the body. The echoes that bounce back are used to form images of tissues and organs. Higher frequencies provide better resolution but penetrate less deeply. Ultrasound is used for diagnostic medical imaging and to guide procedures by providing real-time visualization of internal structures. It has advantages of being noninvasive, having no known health effects, and being relatively inexpensive compared to other imaging modalities.
Anatomy of external and middle ear by dr. faisal rahmanFaisalRahman153
This includes anatomy of external and middle ear with their clinical co relations. Embryology is also discussed here. Pinna, External auditory canal, Tympanic membrane, Middle ear Cleft, Mastoid and Auditory tube topics are included.
1. Ultrasound uses high frequency sound waves and their echoes to produce medical images of the inside of the body. 2. The ultrasound machine transmits sound pulses into the body using a probe, which detects the echoes reflected back from tissues and organs. 3. By measuring the time it takes for the echoes to return, the machine can calculate distances to internal structures and display a 2D image on the screen based on the intensities of the echoes.
otosclerosis....
stapedectomy vs stapedotomy
complication of otosclerotic surgery
management of otosclerotic surgery complications
techniques
latest trends
Ultrasound Machine-A Revolution In Medical ImagingRAVI KANT
What is medical imaging?
Why ultrasound imaging is required?
History of ultrasound
What is ultrasound
Physical definition
Medical definition
Ultrasound production
The Returning echo
Doppler effect
What is Doppler ultrasound
Principles of instrumentation in ultrasonography
Transmitter and receiver circuits of ultrasound
Mechanical assembly of ultrasound machine
Manufacturing companies of USG
Sonoscape S40 color Doppler ultrasound system
Clinical applications of ultrasound
Future of ultraso
This document provides an overview of the history and physics of ultrasound machines. It discusses how ultrasound works, including how sound waves are produced and received, how images are formed, and factors that affect image quality. The key components of an ultrasound machine are described, including the transducer probe, central processing unit, display, and storage devices. Different ultrasound imaging modes like A-mode, B-mode, and M-mode are introduced along with common medical applications of ultrasound imaging.
The document provides an overview of ultrasound physics and optimization for ultrasound-guided regional anesthesia. It discusses the basics of sound waves and how they interact with tissues. Key points include: the piezoelectric effect which converts mechanical energy to electrical energy; acoustic impedance and how it affects reflection and refraction; and factors that influence image quality such as transducer selection, gain, depth, and angle of insonation. Common artifacts are also reviewed. Proper ergonomics, scanning techniques, and safety strategies are emphasized for obtaining optimized ultrasound images.
This document provides an overview of ultrasound physics basics. It discusses how ultrasound uses sound waves between 10-20 MHz to generate images. Sound waves are longitudinal waves that travel through materials at different speeds depending on compressibility and density. Ultrasound imaging works by transmitting pulses into the body and receiving echoes, with transducers converting between electrical and sound signals. Factors like frequency, beam characteristics, and tissue interactions impact the resulting images and potential artifacts. Understanding ultrasound physics principles is important for optimizing scans and interpreting images.
The document discusses bone conduction hearing devices (BCHDs) and their components, functioning, advantages over conventional hearing aids, and surgical classifications. It provides details on the normal routes of bone conduction, components of acoustic and implantable hearing devices, pathophysiology of cochlear deafness addressed by implantable devices, and terminology used. It also outlines clinical indications and criteria for BCHDs as well as some limitations.
a detailed description of middle ear anatomy including embyology, development, temporal bone anatomy, anatomical variations, ossicles, mucosal folds, fissures, tympanic membrane, chorda tympani, nerve supply, various walls of middle ear, tegmen, windows
in short- everything about middle ear anatomy in detail
The document discusses hemoptysis, defined as bleeding from the lungs or bronchial tubes. It describes the dual arterial blood supply to the lungs from the pulmonary and bronchial arteries. Conditions that reduce pulmonary arterial flow can increase bronchial artery contribution, making those vessels prone to rupture and bleeding. A comprehensive evaluation of hemoptysis includes history, physical exam, labs, chest imaging including radiography and CT, and bronchoscopy. CT is particularly useful for evaluating underlying lung abnormalities and identifying abnormal bronchial vessels to guide treatment.
This document provides an overview of ultrasound physics principles:
1. It describes how ultrasound works by using a transducer to emit pulses that reflect off tissues and are received back to form an image, and how tissue properties like density and velocity affect reflection and transmission.
2. It explains key ultrasound concepts such as wavelength, frequency, amplitude, acoustic impedance, and gain which determine image quality, as well as Doppler effects which provide blood flow information.
3. The primary components of an ultrasound system are described as the transducer, which emits and receives sound, and the imaging instrument which processes the returning echoes to display an image.
Ultrasound uses high frequency sound waves to image internal structures. It works by sending sound waves into the body which bounce off tissues and organs, creating echoes. The echoes are detected and used to produce images on screen. Key physics principles include velocity, wavelength, frequency and amplitude of the sound waves. How the waves interact with different tissues through reflection, transmission, scattering and attenuation impacts image quality. Resolution, beamforming and processing power determine how well an ultrasound system can distinguish between tissues. Doppler and colour Doppler utilize the Doppler effect to evaluate blood flow velocity and direction to provide functional information.
Vocal nodules are benign, bilateral growths on the vocal cords caused by overuse or misuse of the voice. They are usually treated with voice therapy and rest, and may require surgery if not improved after 3-6 months. Vocal polyps are also benign growths but are usually unilateral and caused by vocal trauma or irritants like smoking. They are typically treated with excision during microlaryngoscopy. Reinke's edema is a bilateral swelling of the vocal cords caused by irritants like smoking, and is treated by removing the fluid or tissue via stripping under microlaryngoscopy along with voice therapy.
The document provides an overview of interpreting chest x-rays, including:
1. It describes the radiologic signs of lobar and segmental lung collapse including displacement of fissures, volume loss, hilar elevation, and crowding of vessels and bronchi.
2. Specific features of collapse in different lung lobes are outlined, such as the triangular density seen in right middle lobe collapse on lateral view.
3. Degree of collapse can affect radiologic findings from subtle increased opacity to complete loss of fissure lines. Additional signs like the superior triangle sign may help with diagnosis.
4. Causes of an opacified hemithorax are discussed, highlighting how mediastinal shift
The document summarizes key aspects of sound physiology and hearing. It describes how sound is produced through vibration, propagated through media, and detected by the ear. It explains the functions of the outer, middle, and inner ear in transmitting sound vibrations and converting them into neural signals. The cochlea analyzes sounds by frequency using a traveling wave mechanism and hair cells that transduce vibrations into electrical signals sent to the brain via the auditory nerve.
Computerized tomography (CT) uses X-rays and digital image processing to generate cross-sectional images of the body. Godfrey Hounsfield invented the first commercially viable CT scanner in 1972. CT scans provide more detailed images than traditional X-rays by using multiple angles to reconstruct cross-sectional slices of the body. Modern CT scanners can obtain these slices quickly, in under one second, allowing imaging of moving structures like the heart.
This document provides information on various endoscopic procedures used in diagnosing and treating conditions of the nasal cavity, throat, esophagus, and lungs. It describes the indications, contraindications, procedures, and potential complications of nasal endoscopy, videolaryngoscopy, esophagoscopy, bronchoscopy, and nasopharyngoscopy/rigid pharyngolaryngoscopy. Key details covered include the diagnostic and therapeutic uses of each scope, as well as size recommendations for pediatric versus adult procedures.
This document provides information on various laryngeal pathologies that can be diagnosed using imaging techniques like CT and MRI. It discusses laryngeal cysts, laryngoceles, thyroglossal cysts, laryngotracheitis, epiglottitis, Wegener's granulomatosis, laryngeal stenosis, vascular malformations, vocal cord paralysis, laryngeal trauma, squamous cell carcinoma, supraglottic carcinoma, glottic carcinoma, transglottic carcinoma, subglottic carcinoma, atypical squamous cell carcinomas, hemangiomas and more. Imaging findings that help diagnose and characterize these conditions are also described.
Este documento proporciona información sobre cómo aplicar temas, modificar fondos y números de diapositivas, y crear patrones y diseños de diapositivas en PowerPoint. Explica que los temas agregan un aspecto elegante de forma rápida, y que existen dos formas de aplicarlos. También describe cómo personalizar fondos, números y estilos de diapositivas, así como crear y modificar patrones y diseños de diapositivas.
2. Flet – instrument dęty drewniany
Zazwyczaj ma postać cienkiej, pustej w środku rurki
Istnieją również flety o innych kształtach, np. okaryna
3. Odmiany fletu
flet poprzeczny – popularny instrument muzyki
poważnej pełniący ważną rolę w orkiestrze
symfonicznej
flet prosty – powszechnie wykorzystywany na
zajęciach wychowania muzycznego w szkołach
podstawowych i gimnazjach oraz do wykonywania
muzyki dawnej
4. Historia
Flet jest jednym z najstarszych znanych
instrumentów muzycznych, używanym
od czasów prehistorycznych – około 36 tysięcy lat.
Jednym z najstarszych fletów jest fletnia Pana, która
składa się z piszczałek (rurek) o różnych długościach,
połączonych ze sobą.
Grano na nich
w starożytnych
Chinach i w Europie
już 500 lat p. n. e.
5. Flet prosty
Jest jednym z najprostszych instrumentów
muzycznych.
Wywodzi się od ludowej fujarki i posiada podobną
konstrukcję.
Starożytne flety, podobnie jak inne instrumenty
z rodziny dętych drewnianych robiono z trzciny, rogów
zwierzęcych, a nawet kości.
6. Odmiany
flet sopranino
- zakres dźwięków f1 do g3
flet sopranowy
- zakres dźwięków c1 do d3
flet altowy
- zakres dźwięków f do g2
flet tenorowy
- zakres dźwięków c do d2
flet basowy
- zakres dźwięków F do g1
7. Materiał
Flety proste produkowane są z drewna lub plastiku.
Flet z dość miękkiego drewna gruszy ma delikatny,
miękki dźwięk (idealny dla melomanów samouków).
Flety z drewna klonu poleca się do gry w zespołach.
Bardziej twarde drewno: śliwy, bukszpanu,
palisandru, tulipanowca czy hebanu doskonale
nadaje się do produkcji fletów koncertowych.
Obecnie produkuje się flety z plastiku
o wysokiej jakości.
8. Źródło dźwięku
Źródłem dźwięku jest drgający wewnątrz instrumentu
słup powietrza (przepływ powietrza).
Siła przepływu powietrza jest regulowana poprzez
zakrywanie otworów w korpusie instrumentu.
9. Wysokość dźwięku
Wysokość dźwięku zależna jest od
ilości drgań na sekundę: im większa
częstotliwość drgań, tym wyższy jest
dźwięk i przeciwnie - im mniejsza
częstotliwość drgań, tym dźwięk jest niższy.
Wysokość dźwięku we flecie zależy od długości rury,
która tworzy instrument. Im dłuższa rura, tym niższy
maksymalny dźwięk można uzyskać, natomiast
dźwięki wyższe uzyskuje się skracając wysokość słupa
powietrza przytykając odpowiednie otwory.
10. Elementy instrumentu muzycznego
Głównym elementem instrumentu muzycznego jest
wibrator – jego własności fizyczne wpływają na
wysokość dźwięku i jego barwę
W przypadku fletu
wibratorem jest drgające
powietrze uderzające
o krawędzie instrumentu
11. Pozostałe elementy
Dwa pozostałe to incytator, czyli
element pobudzający wibrator
do drgań i rezonator – element
zwiększający głośność dźwięku.
W instrumentach dętych incytator to siła pobudzająca
wibrator (powietrze) do drgań, czyli zadęcie
Zarówno incytator, jak i rezonator wpływają na barwę
dźwięku wytwarzanego przez instrument muzyczny.
12. Barwa dźwięku
Barwa dźwięku zależy od konstrukcji
instrumentu, rodzaju materiału,
z którego jest wykonany, rodzaju
wibratora, sposobu zadęcia itd.
Dźwięk składa się nie tylko z fali podstawowej, ale
także dodatkowych fal zwanych alikwotami o innych
częstotliwościach. Barwa dźwięku zależy właśnie od
tych „dodatków”.
13. Natężenie dźwięku
Natężeniem dźwięku nazywamy
stosunek energii docierającej
w jednostce czasu do danej
powierzchni (mocy fali) do pola tej powierzchni.
Badania wykazały, że natężenie dźwięku (o stałej
częstotliwości) jest proporcjonalne do kwadratu
amplitudy, dlatego dźwięki słabe różnią się od silnych
przede wszystkim mniejszą amplitudą fali.
14. Sposób wydobycia dźwięku
Wybór wysokości dźwięku
na flecie odbywa się poprzez
odpowiednie otwieranie
lub zamykanie otworów
położonych wzdłuż rury.
Grający dmie w ustnik, powietrze w komorze
rezonacyjnej zostaje rozdzielone na dwa strumienie,
z którego jeden opuszcza instrument przez otwartą
szczelinę, a drugi poddany wibracji przepływa przez
prostą rurę.
15. Drgania cząsteczek powietrza
We flecie dźwięk „rodzi się” samoistnie
we wdmuchiwanym słupie powietrza.
Gdy cząsteczki zaczną się poruszać, pojawia się reakcja
łańcuchowa z cząstkami sąsiednimi. Przesyłanie ruchu
powietrza, nazywane podłużnym przemieszczaniem
się drgań, polega na naprzemiennym rozrzedzaniu
i zagęszczaniu powietrza.
16. Fale dźwiękowe we flecie
Fale dźwiękowe są podłużnymi falami mechanicznymi
rozchodzącymi się w powietrzu (fale dźwiękowe to
rodzaj fal ciśnienia).
W rurce następuje na przemian
zagęszczanie i rozrzedzanie
warstw zawartego w niej
powietrza, nadając jego
cząsteczkom ruch oscylacyjny
do przodu i do tyłu.
17. Rezonans kolumn powietrza
Fala dźwiękowa poruszając się
w powietrzu odbija się od ścianki
fletu. W wyniku odbić dochodzi do
rezonansów.
Częstotliwości rezonansu w rurce są
uzależnione od długości rurki, jej
kształtu, oraz czy jest zamknięty czy
otwarty jej koniec.
Pierwsze trzy rezonanse
w otwartej rurze.
Wykres przedstawia ciśnienie.
18. Częstotliwości rezonansowe
Flet zachowuje się jak otwarta cylindryczna rura.
Częstotliwości rezonansowe otwartych cylindrycznych
rur są określone wzorem:
gdzie:
n – liczba naturalna
L – długość rury
v – prędkość dźwięku w powietrzu (w przybliżeniu 344 m/s w 20°C)
19. Podsumowanie
Na flecie gra się ustami,
kierując strumień powietrza
w stronę otworu zwanego
wargowym, który znajduje
się na jednym z końców fletu.
Częstotliwość drgającego słupa powietrza może być
zwiększona przez siłę dmuchania. Oprócz tego flet
wyposażony jest w osiem otworów, które zasłania się
lub odsłania końcami palców, co odpowiednio zmienia
wysokość dźwięku. Jeżeli otwór jest odsłonięty,
efektywna długość drgającego słupa powietrza jest
mniejsza, dlatego otrzymany dźwięk jest wyższy.