Pendulum, Medical, Industrial Wave Applications Pendulum, Medical, Industrial

Pendulum Any mass on a string that sways back and forth due to the force of gravity. It can demonstrate the oscillatory motion that defines a wave. The energy it has is constantly being transferred between gravitational potential energy and kinetic energy.

Pendulum The period of a simple pendulum can be found using the length of the string and the constant acceleration due to gravity. 𝑝𝑒𝑟𝑖𝑜𝑑=2𝜋 𝑙𝑒𝑛𝑔𝑡ℎ 𝑎𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝑑𝑢𝑒 𝑡𝑜 𝑔𝑟𝑎𝑣𝑖𝑡𝑦 𝑇=2𝜋 𝐿 𝑔

Example Problem What is the period of a simple pendulum on Earth that is 75 cm long?

Medical Applications X-rays and ultrasounds are two common procedures that can be used to diagnose illness or injury. X-rays are a type of electromagnetic waves that have very small wavelengths. The x-rays take images of the internal structure of the body by placing a film behind the patient as the x-rays are projected onto the area of the body to be imaged. Different shading on the film indicates the different densities of the area of the body.

Medical Applications Ultrasounds are used to see the internal structure of the body. An ultrasound is a sound wave with a frequency greater than 20 kHz, which is well above the range of human hearing. The wave can penetrate the soft tissue but bounces off of higher density organs and bones. A machine reads the reflected sound waves and converts them into images. An echocardiogram is an ultrasound performed on the heart that also uses the Doppler Effect to determine the way the blood is flowing.

Industrial Applications Radios, televisions, microwave ovens, navigation, lasers, and even some cleaning techniques rely on wave behaviors to function and are essential to the operation of many industrial settings. Radios receive electromagnetic radio waves that are sent from a station. These radio waves have the longest wavelengths of any type of electromagnetic waves, so they can travel long distances. In AM radios, the amplitude is changed or “modulated.” In the FM radios, the frequency of the wave is modulated. Analog televisions also receive signals through higher frequency radio waves.

Industrial Applications Microwaves use electromagnetic waves to heat food. Waves with similar frequencies are also used in communication over short distances through Bluetooth devices. Radar uses high frequency radio waves to determine the location of an object. Radar equipment sends out a wave pulse and measures how long it takes to return to determine an object’s location. Sonar devices follow the same process, but they use sound waves instead.

Industrial Applications Lasers produce light within an extremely narrow range of wavelengths and are used in many tools to cut materials or scan barcodes. DVD and Blu-Ray players use lasers to read the tiny grooves that hold information on the surface of a disk. The light from a Blu-Ray player has a shorter wavelength of 405 nm allowing the grooves on the disk to hold more information the be smaller, so more information can be stored on the disk. Lasers can be used in multiple industrial applications such as laser cutters, laser welders, laser levels, and laser scanning, just to name a few.

Industrial Applications Ultrasonic Cleaning: Items are placed in a basket, then lowered into a machine which contains fluid (can be tap water or a specialized cleaning solution). When the machine is turned on, a transducer in the machine produces high frequency sound waves. Dirt and debris is removed from the equipment by the ultrasonic vibrations within the cleaning fluid. The equipment is then taken out of the solution and is clean. These ultrasonic cleaners can be used to clean medical instruments, tools, coins, watches, jewelry, and electronic equipment.