1. The Uses Ultrasonics

2. Ponder this…
When I ask you to describe what sound is, what comes to mind:
A dog barking? A television with the volume turned up? Music playing inside a car? The hum of traffic outside it?
Image Source/Rights: Photo by Nextvoyage from Pexels, 2016, CC0

3. The magic of sound
By the end of this presentation you should be able to answer the following:
What is sound?
What are the types of sound?
How can ultrasound be used to help us in everyday life?
Why are there different ways to measure with ultrasonic devices?
Give students the target outcomes for the lesson. Make sure they have time throughout the lesson slides to pause and discuss with their precision partner.

4. What is sound?
Sounds is the movement of energy in vibrations that travel through the air/water as sound waves.
When the vibrations move through air they disturb it causing it to expand and contract.
Sound also can bounce off objects, changing the direction and strength of the vibrations.

5. Vocabulary
The wavelength represents variation in air pressure and is the distance over which the wave’s shape repeats.
An oscillation of a wave is defined how long it takes for a wave to move from starting position, one position to the next and back to the start.
Amplitude refers to the intensity or power of the sound wave, and relates to volume.
The frequency of a wave is defined as number of oscillations the wave completes in a certain amount of time (usually seconds).
The unit of measurement for sound is a hertz (Hz), and it is based on how many oscillations occur per second.
The frequency of a wave is defined as number of cycles this wave completes in a unit of time. This unit of time is typically taken to be a second. Frequency of 1Hz, or one Hertz, indicates that the wave oscillates one cycle over a time period of 1 second.

6. Image of a sound wave
Begin by referring back to the vocabulary from the previous page. Identify oscillation, frequency, and tell students the oscillations could be measured in hertz.
Also, point out that wavelength is the distance between two points at the same position (crest, trough, starting position). I would wait on explaining amplitude.
Image Source/Rights: Sabina Schill, 2018, University of Colorado at Boulder

7. Sound comes in many frequencies
Can humans hear all types of sounds?
Infrasound
Ultrasound
Audible frequencies
200MHz
2MHz
20Hz
20KHz
Sound waves are everywhere around us even when we cannot hear them. Sound can travel at frequencies above or below what our ears can register. Some animals can hear sounds with frequencies below what humans can register. Some sounds have too high of a frequency for us to hear.
Image Source/Rights: 2012 Irina Igel, Polytechnic Institute of NYU,
No, audible frequencies are what we can detect.

8. Ultrasonic applications
Sound frequencies below and above human threshold have been used to support engineering and medical fields. Ultrasounds can be used to take images of soft tissues and it does not risk exposure to radiation, like an x-ray would. The use of ultrasonic waves is also incorporated into navigation and detection of items in water (SONAR).
Source:
Image Source/Rights:
2017 FDA,
2017 NOAA,
2006 Moroder, CC BY-SA 3.0
2012 Irina Igel, Polytechnic Institute of NYU,
Infrasound
Ultrasound
Audible frequencies
200MHz
2MHz
20Hz
20KHz

9. When sound travels
As sound travels it can be reflected, refracted, or focused.
Reflection and refraction occur when the waves interact with a medium of differing properties. Focused sound may use a piece of technology to direct it.
Sound travels at slower speeds in gases than liquids; it travels the fastest in solids.
Sound travels at 343 m/s in air; it travels at 1,484 m/s in water; and at 5,120 m/s in iron.
source:

10. Producing ultrasound waves
One way to replicate ultrasound wave frequencies is with a transducer.
Depending on the direction, the transducers may be positioned at an angle rather than perpendicular to the object being tested.
The image is showing a pulse-echo transducer with an angle beam rather than direct beam because of the location and direction of transducer B.
Image Source/Rights: 2017 Kendra Randolph, Michigan State University

11. Uses of Ultrasonics
There are so many uses in the real world using ultrasonic devices. Many of these applications require that sound travel through a medium other than air. Examples include:
Diagnostic and medical imaging
Communication and echolocation; SONAR
Engineering Design

12. Measuring distance with sound
Ultrasonic waves can be used to accurately measure distances with special sensors.
Sender
Receiver
14cm
Reflected wave
Original wave
Image
Image source: 2012 Irina Igel, AMPS GK-12 Program, Polytechnic Institute of New York University.
In air, sound travels at a constant speed, which means we can measure distance by seeing how long it takes for a sound to hit and object and bounce back to the sensor.

13. Why use a sensor
image source:
This is the actual sensor used in the activity with the Arduino microcontroller. On the previous slide it was labeled sender and receiver. These relate to our trigger and echo pins on the sensors themselves.
With the use of sensors like the ones above and the use of computer programming, many opportunities are available for humans to accurately measure distance at a faster more reliable pace than our use of a ruler or tape measure.

14. Let’s go back to those questions...
Turn and talk to your partner.
What is sound?
What are the types of sound?
How can ultrasound be used to help us in our lives?
Why are there different ways to measure with ultrasonic devices?
Extension: How might we use ultrasonic sensors that measure distance to our advantage in our lives?
Have students work with their partner to discuss the 4 questions. It would be up to the discretion of the teacher to decide how students would present their ideas. I would consider some sort of graphic or visual. Make sure to stress to students though “Being able to answer these questions is your ticket to joining another group to work on your application and design of your own ultrasonic sensors.”