Speed of Light – Speed of Sound

• You can see a flash of Lightning almost instantly

• But it takes a while before you hear the thunder

• You can count to tell how far away it is

• Sound takes about 5 seconds to go 1 mile

Sound Waves

What can they hear?

• Humans – up to 20,000 Hz

• Dogs – up to 40,000 Hz

• Cats – up to 60,000 Hz

• Bats – up to 100,000 Hz

• Dolphins – up to 150,000 Hz

What do sound waves look like?

Human

Thunder = low frequency

What are echoes?

What is Echolocation ?

"Echolocation is the use of sound waves and echoes to determine where objects are in space”

In other words, echoes help to find the location of an object.

http://askabiologist.asu.edu/echolocation

How is Echolocation used by animals ?

http://askabiologist.asu.edu/sites/default/files/echolocation.jpg

• Bats send out sound waves using their mouth or nose. • When the sound hits an object, an echo comes back. • The bat can identify an object by the sound of the echo.

Blind as a Bat?

• Most bats regularly eat flying insects. • Bats can see as well as humans, but

echolocation is much more important to them than their eyesight for finding food.

• Bat’s Echolocation is so precise that it can detect an object the width of a human hair.

• Mother bats who are feeding their babies, may catch and eat up to 4500 insects in one night!

They can even tell the size, shape and texture of a tiny insect from its echo .

Some moths have developed ways to get away or confuse bats, such as:

• Furry wings that don't reflect bat echolocation pulses.

• Sensitive membranes that can 'hear' echolocation pulses. When the pulses are detected, the moths fly in crazy patterns or fold their wings and dive to confuse their hunters.

http://academic.reed.edu/biology/professors/srenn/pages/teaching/web_2007/pf_site/adaptation.html

Bats using Ultrasound to Catch Prey

Click on photo to start video

Books you might enjoy!

The Tiger Moth

The Tiger Moth Can can emit ultrasonic clicks to "jam" a Bat's sonar!This moth produces ultrasound not to communicate, but as a way to protect itself. By producing ultrasound of its own, it is able to ward off bats by acting as a radar jammer, confusing the bats so that the moth cannot be located. By doing this, they add another weapon to their survival mechanisms that also includes poison. http://en.wikipedia.org/wiki/Arctiidae

Philippine TarsierThe tiny Tarsier, only 4 inches long, can communicate using ultrasound. The Tarsier is the only primate known to communicate in this way.

The Dolphin uses nasal passages to make a click and sends it through its forehead, which focuses the sounds together into a beam before sending it into the water.

• When the sound hits an object in the water, it bounces back to the dolphin as an echo.

• The dolphin absorbs this returning echo through its jaw.• A passage of fat from the jaw conducts the sound to the

dolphin's inner ear• The dolphin can tell things about the object, such as size,

shape and material.

The crickets, Arachnoscelis, is from the Katydid family. Itlives in the tropical rain forests, and can produce the highest-frequency ultrasound of any known insect. These sounds are emitted by the lonely male, which makes its presence known with a burst of intense sounds. Listen to their calls!

Arachnoscelis arachnoids, a rare species of katydid from Central Northeast of Colombia, uses elastic energy and wing movement to reach volumes greater than 110 decibels, which is louder than a diesel truck or a subway train.http://www.sci-news.com/biology/science-bushcricket-colombia-01265.html

House mice use Ultrasonic sounds to attract mates. Rats and other rodents also use it to communicate.

The Huia Cavitympanum is the only known frog species that can communicate using purely ultrasonic calls. This unusual frog lives in the Philippines. These frogs can hear sounds up to 38 kilohertz, the highest frequency any amphibian species has been known to hear.

What are some of the ways animals use Ultrasound andEcholocation?

As you have seen, many animals use Echolocation to help them move about in low light and to locate food. They also use Ultrasonic sounds to communicate.

From watching animals and through scientific experiments, humans have learned to use Echolocation, SONAR and also RADAR in many different ways.

Science Technology Engineering

• Science looks at Nature and explains it

• Technology figures out how to make Science useful

• Engineering builds new things using Technology

Humans cannot create or hear ultrasound, by themselves, but we can make devices that do this for us.

How Is Echolocation used by humans?

How it works: 1. A chirp is emitted from the “speaker”2. It bounces off of an object3. The echo returns to the microphone4. The time it takes to travel to the object and back is used to figure out the distance

Robots

http://www.dailymail.co.uk/sciencetech/article-2261574/Audi-A6-Our-man-Las-Vegas-highway-road-test-car-drives--parks--itself.html

Driverless Cars

http://wbbw1.bwbx.io/cms/2012-04-09/0409_GigaOM_car_630x420.jpg

http://www.economist.com/node/21560989

The Driverless Car is equipped with radar sensors monitoring up to 820ft ahead, a wide-angle video camera that monitors lane markings. It also has 8 Ultrasonic Sensors. It can even park itself, squeezing in to within 4in of another car.

Read more: http://www.dailymail.co.uk/sciencetech/article-2261574/Audi-A6-Our-man-Las-Vegas-highway-road-test-car-drives--parks--itself.html#ixzz2xT65l5od

http://america.aljazeera.com/watch/shows/techknow/blog/2013/10/24/-techknow-need-toknow6questionsyoushouldaskaboutdriverlesscars.html

The Tactic Device for the Blind

How the Tactic Works

• The Tactic can help the blind move around safely.

• It is mounted on your wrist and uses ultrasonic sensors set above the knuckles that can pick up the distance of objects from one inch to 10 feet away

• It then translates that distance to pressure on the wrist--the closer the object, the more pressure on the wrist.

Read more at: http://phys.org/news/2011-09-tacit-device-safety-video.html#jCp

The Hand Bat

• The Hand Bat is a simple Do It Yourself (DIY) device similar to the Tactic

• It uses an Arduino Microcomputer, an ultrasonic sensor and a beeper

• It is built in a low-cost waterproof flashlight case

• When you point it in different directions, it sends out an ultrasonic sound and listens for the echo

• It figures out the distance and tells the user how far away an object is with different sounds

Ben Underwood was a very special kid. He was blind since the age of 3 when he had to have both eyes removed due to cancer. His mother helped him to believe that he could still do mostly anything he wanted to do even though he could not see.

http://www.theguardian.com/lifeandstyle/2007/jan/27/familyandrelationships.family2

Human Echolocation

Ben learned to use clicking sounds and echolocation in the same way in which bats and dolphins use it. Using this method to avoid obstacles, he was able to ride bikes, play basketball and participate in

many other activities most blind people are never able to do. Sadly, Ben passed away in 2009 after the cancer returned. Learn more: http://www.youtube.com/watch?v=AiBeLoB6CKE

The True Story of Ben Underwood