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Nelson EducationSchoolPhysics 12 College Preparation | ||||||||||||||||||||||||||||||||||||||||||||||||||
Web LinksUNIT 5: COMMUNICATIONS TECHNOLOGYClick on a section below for related Web activities: Chapter 9: Communication with Sound 9.5 Interference of Pulses and Waves 9.10 Sound Communications Technology Chapter 10: Communication with Light 10.3 Reflection of Electromagnetic Waves 10.4 Refraction and Total Internal Reflection 10.6 Communications and Electromagnetic Waves
Unit 5
CHAPTER 9: COMMUNICATION WITH SOUND
p. 443 3. One application of the principle of superposition is noise-cancellation headphones. These electronic headphones are more effective than methods of protection that simply cover the ears. Pilots of some noisy military aircraft wear these headphones to protect their hearing. Some musicians also use this technology. (a) Based on the name of these headphones, do you think they make use of constructive or destructive interference? Explain your answer. (b) The noise sensors in a headphone receive the signal shown in Figure 7. Draw the signal that the electronic components must create to cancel the noise. (c) Research noise-cancellation and noise-reduction headphones. Describe briefly what you discover about their operation and use. Learn about noise cancellation headphones for airline passengers. This page lists the features, technical specifications of the headphones, and the physics behind how it works. This page describes Pro-Headphones noise cancellation headphones for audio professionals and explains how it works.
This page describes the active noise reduction headsets and passive noise reduction headsets for pilots, aviators, passengers, and airport ground cursor workers in noisy environments.
p. 457 Combine your love of music with skill as a musical instrument repair technician or fine craftsperson building precision instruments. State of Minnesota-Musical Instrument Repair Technician This site explains what a musical instrument repair technician does, the knowledge, skills, and abilities required, and examples of positions available. Career Advice--Instrument Repair Technician This site describes the job of an instrument repair technician, the skills, educational requirements, and an outlook of job prospects.
Career Connection p. 460 As a radiation or ultrasound medical imaging technician, you assist doctors in the diagnosis of problems or disease. With further training, you can move into more complex technologies, such as CT (computed tomography) and MRI (magnetic resonance imaging). There are employment opportunities in hospitals, clinics, and in industry. This home page provides information about Mohawk College's full-time and part-time programs and courses, student services, application process, financial aid, and their graduate employment report. Fanshawe College--Medical Radiation Technology This site outlines information about Fanshawe College's medical radiation technology program, including a program description, list of career opportunities, program eligibility and selection criteria, and tuition fees. Confederation College--Medical Radiation Technology This page describes Confederation College's seven semester medical radiation technology diploma program, the admission requirements, selection criteria, physical demands of the job, and employment opportunities.
Did You Know?
p. 460 Musicians' Hearing Studies have shown that approximately one-third of rock musicians and one-half of classical musicians have a measurable hearing loss. Another study found that, compared with students who did not play in a band, twice as many high school students who played in a band had a measurable hearing loss.
This article describes noise induced hearing loss, the hazards, and how musicians can protect themselves. Musicians--Protecting the Professional Ear This site informs musicians about the risk of inner ear damage, how to protect their ears, and simple steps toward hearing conservation.
Explore an Issue p. 462 How Can the Effects of Loud Sounds Be Reduced? Exposure to loud sounds can increase stress and blood pressure, cause hearing loss, reduce rest and sleep, and affect learning. The effects of the loud sounds depend on the intensity of the sounds, the length of exposure time, and how often the listener is exposed to them. To explore the effects of loud sounds in our society and means of reducing them, your class can share the responsibility of researching the following areas: workplace noise, environmental noise, household noise, recreational noise, and rural noise. This noise pollution clearinghouse site aims to raise awareness about noise pollution, and provides a plethora of links to online noise related resources. This Web site describes specific noise environments, what we can do to reduce noise pollution, and how we can protect ourselves from the damaging effects of excessive noise.
Section 9.10 Practice Questions p. 473 5. Bursts of loud bass sounds on a car speaker system require more power than is available from a car's battery. Large capacitors, called diamond-like capacitors or carbon ultra capacitors , provide enough power for short time intervals to play the bass sounds. Research this technology on the Internet. (a) What is the current capacitance of these capacitors? (Recall from Chapter 8 that capacitance is measured in farads, F.) (b) Describe features of these capacitors, including their dimensions, maximum current, cost, and other variables. (c) What other technology benefits from the use of high-farad capacitors? Second Generation of Ultra-Caps Now Up to 5000 Farads per Cell This article describes the improved electrode technology and revolutionary design that has brought rise to the newest Ultra-Caps by EPCOS.
Diamond-Like Carbon (DLC) Capacitors This page briefly describes characteristics of the diamond-like carbon capacitor, as well as its applications and advantages over other capacitors.
Ion Beam Diamond-Like Carbon (DLC) Capacitors This article discusses the technology behind the diamond-like carbon capacitor, its applications, and potential in military and commercial activities. Career Connectionp. 474 Post-secondary programs for audio engineers vary from 30 weeks to 1 year. There are many opportunities for audio engineers using state-of-the-art digital technologies, for example, recording musical artists, post-production for the movie and television industry, and designing and producing the sound components for video games.
This Ontario Institute of Audio Recording Technology site describes its Audio program, information on admission requirements, and career opportunities for graduates. This site provides information about Recording Arts Canada's diploma program in audio engineering and multimedia production. Also provided are registration guidelines for details on application and admission procedures.
Fanshawe College-Recording Industry-Digital Applications This site outlines information about Fanshawe College's one-year post-graduate certificate program in audio recording technology, including a program description, list of career opportunities, program eligibility and selection criteria, and tuition fees.
Career-College: Audio Recording Academy This Audio Recording Academy site provides information about its 30-week hands-on course in audio recording.
Chapter 10: COMMUNICATION WITH LIGHT
p. 501 With the current digital revolution, the field of telecommunications has become very exciting, especially in the area of wireless products. Specialists in this field design, service, and sell high-tech electronic products. Equally important are the telecommunications specialists needed to install and maintain the actual communications systems. This Algonquin College website provides information about the degree programs in interactive media and design and network technology. This home page provides information about Mohawk College's full-time and part-time programs and courses, student services, application process, financial aid, and their graduate employment report. Canadian Council of Technicians and Technologists This site describes the Canadian Council of Technicians and Technologists, and the products and services they provide for certified science and engineering technologists across Canada.
Try This Activity: Dish Hunt
p. 502
Look at several satellite dishes in your area, and answer these questions: What size, shape, and design are the dishes? Which way are they pointed? Are they all pointed exactly the same direction? Research uses of satellite dishes. Explain why the dishes have the characteristics you observed. (Refer to shapes of curved reflectors, focal length, focal point, and wavelengths of waves.)
This page describes how satellites work, including signal strength, frequency and bandwidths, and the uses of satellite antennas or dishes.
This page describes the design of satellite dishes and explains the importance of the parabola-shaped reflector.
This page explains how the parabolic reflector works, and the physics behind the construction and operation of satellite dishes.
Did You Know?
p. 503 Communications Airships Floating airships are an alternative to satellite technology for two-way Internet communications. A Canadian company, 21 st Century Airships, is a leader in the design of these airships. These spherical airships float at an altitude of approximately 19.8 km, about twice the cruising altitude of commercial aircraft. They are highly maneuverable, use solar energy to operate slow-moving propellers, and are easily retrieved for repair and maintenance. This 21st Century Airships Inc. homepage displays a pictorial history of the company's prototypes, the technology, and the applications of this innovative type of airship. This article describes how communication airships could replace costly satellites as weather predicting devices.
p. 507 An understanding of refraction is vital to the manufacture of eyeglasses, contact lenses, and other devices used to improve vision. Opticians are needed in medical clinics as well as in retail optical dispensaries. Knowledgeable and trained salespersons representing eyewear manufacturers are also important. This site describes Seneca College's Opticianry diploma program, the structure of the program, what courses are required, and the program learning outcomes. This site provides information about Georgian College's Opticianry program, courses, registration, admission requirements, program learning outcomes, and graduation requirements.
Section 10.6 Practice Questions p. 522 5. Holography has many practical applications. (a) What is the purpose of a hologram on a credit card? (b) Find other examples of the applications of holography using resources of your choice. Describe one example. Existing Technical Applications for Holography This site lists and describes the technical applications for holography and information on vibrational analysis, non-destructive testing, airflow visualization, and data storage media. Holography: Medical Applications This site describes the various medical applications of holography, including applications in X-ray, endoscopy, medical tomography, ophthalmology, otology, and dentistry.
Learn about the history of holography and which credit card was the first to carry embossed holograms and which year this occurred.
p. 524 8. Find out more about one of the inventors (Alexander Graham Bell, Reginald Fessenden, and Guglielmo Marconi) featured in this case study. Write a brief report using information that has not been presented here. This site allows you to search information on famous inventors, their inventions, and also provides a link to several related online resources.
p. 529 7. The study of the interrelationship between light and electronics is called photonics . Photonics is a fast-growing technology in Canada, with many career opportunities. For example, a college graduate in photonics can qualify for positions in maintenance, repair, and technical sales involving photo imaging, fibre optics, electronic printing, consumer electronics, and telecommunications. Visit a few of the many Web sites available, and make a list of careers in photonics of interest to you. This site outlines the job description, required education, specific duties, and possible career opportunities for photonics technologists and technicians. It also provides a link that lists recommended high school courses students should take to prepare them for these careers.
p. 536 A Snoezelen room is filled with sensory-perception devices that stimulate whatever sense is challenged. Snoezelen facilities were developed in Holland in the late 1970s and have been built in hundreds of locations around the world, including Canada. Several Web sites are devoted to this type of communication. This page describes a Snoezelen room, and the visual, tactile, auditory, and olfactory stimulation and complimentary therapies provided to patients.
This page provides information on the Crystal Bay Centre Snoezelen room, as well as the philosophy and history of Snoezelen. This page describes what the Snoezelen room is, what it is for, how it can be used and the cost of using such a room.
p. 543 45. Night-vision goggles are often used in peacekeeping and military operations. The green colour comes from the type of phosphors used on the screen in the goggles. Research night-vision goggles. (a) Explain the use of transducers and an amplifier in this technology. (b) How does the principle of operation differ from the one used to obtain an IR image? (c) What are the advantages and disadvantages of night-vision goggles? This site provides information on night vision goggles, binoculars, monoculars, and rifle scopes. This physlink.com page explains the laws of physics that govern the operation of night-vision goggles. This page explains the physics behind night vision goggles technology, its applications, and its advantages and disadvantages.
p. 544 46. The use of sonar by the U.S. Navy is controversial. The Navy performs underwater sonar tests with signals as loud as 215 dB. However, at 180 dB, a whale's ears can explode. Dozens of whales--and dolphins--have been found stranded on beaches along the Atlantic and Pacific coasts after the Navy performed tests. (a) How does the intensity level of the sonar compare with the threshold of pain for human hearing? (b) Research the "Surveillance Towed Array Sensor System" (or SURTASS LFA). Describe what you discover about its purpose and results. (c) Do you think the U.S. Navy should continue to use this system? Justify your response.
Surveillance Towed Array Sensor System (SURTASS) This page describes the Surveillance Towed Array Sensor System Intelligence Resource Program, which detects, tracks and reports submarine contacts at long range.
The Surveillance Towed Array Sensor System Low Frequency Activity is a new sonar used by the US Navy for national security.
Protecting Whales from Dangerous Sonar This page describes the effects of ocean noise pollution on whales and other marine life. Effects of Human-Made Sound on the Behaviour of Whales This page discusses reactions of marine animals to the Navy's SURTASS Low Frequency Active sonar signals. It also provides information on Cornell University's Bioacoustics research project, and results of current research.
p. 544 49. The technology of recording sounds in nature, such as bird songs, was improved by a Canadian invention called the "Dan Gibson microphone," named after its inventor. Canadian companies applying this technology are world leaders in making nature and environmental sound recordings and wildlife movies. Research this technology. (a) Describe the principle of operation of the Dan Gibson microphone. (b) What difficulties do sound production people face in obtaining natural sounds? How are these difficulties overcome? (c) Evaluate the contributions to communications of at least one of the following companies: Earth noise; Somerset Entertainment (formerly Solitudes Ltd.); Holborne Distributing Company. History of Environmental Sound Productions Learn about the history of environmental sound recording and the contributions of Dan Gibson. Learn about the challenges and rewards of recording natural sounds. Also learn about the selection of cassette, open-reel, and digital recorders available. This Somerset Entertainment's homepage describes what this company does, and popular music labels under its banner. Capturing the Sound of Silence This article discusses the entertainment companies that hold the largest share in the market of environmental and nature sound recordings, including Dan Gibson's contributions.
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