Page 349: Sonar
How Submarines Work
Visit this site to find out about sound navigation and ranging (sonar). Scroll down to read about active and passive sonar systems. Dolphins use a type of sonar called echolocation underwater to locate prey. Do dolphins use active or passive sonar?
Sonar – The Ultimate Sound Wave
Go to this site to learn all about sonar. Scroll down to read about how sonar works, why it is important, and who uses it. How might sonar be used in the future?
NOVA Online: Experiment with Sonar
At this site you can learn more about how sonar can help you see with sound waves. Watch the animation of a towed sonar array and read the captions. Then click on find out what sonar is used for. How is sonar used by people who fish for a living?
Communication and Echolocation
Go to this Sea World site to learn about echolocation in dolphins, one kind of toothed whale. Scroll down to find out how dolphins produce sounds that they use for echolocation.
What is dolphin echolocation?
At this site you can learn about some experiments in which dolphins were able to locate objects by echolocation even when their eyes were covered. Why do dolphins use echolocation?
Echolocation Mechanism in Dolphins
Visit this University of New Brunswick, Canada site to read a definition of echolocation and to learn about echolocation in dolphins. Scroll down and click on Sound of dolphin echolocating to hear some interesting sounds.
Seeing in the Dark
Visit this site by Bat Conservation International to learn all about bats and their use of echolocation. Scroll down to read about the amplitude and frequency of calls made for different echolocation purposes.
More about bat echolocation
Go to this site by the Singapore Zoological Gardens to learn more about why and how bats echolocate. Scroll down to find out how moths combat the echolocating bats that eat moths. This is a very interesting site.
Bat Echolocation Station
At this Oakland Museum of California site you can see an online exhibit and view an animation of echolocation. Scroll down and click on any bat photo to hear its echolocation clicks (transposed to a lower frequency so you can hear it) and view a sonogram of the clicks.
Page 361: Reverberation in Concert Halls
At this site you can read about some of the physics involved in the calculation of reverberation in concert halls. Scroll down to read about reverberation time. What is a desirable reverberation time in a concert hall?
Page 367: Why Candy Wrappers Crackle and Pop
The deafening science of candy wrappers
Visit this site to read about an experiment to determine why unwrapping candy makes so much noise. The scientists discovered the annoying sound of a candy wrapper is a series of discrete clicks and pops. Why does a candy wrapper click and pop?
Snap, crackle and pop
Go to this site to learn more about why creased and folded candy wrappers make noise when they are opened. Some people try to minimize the noise by opening candy wrappers slowly. Why doesn’t this help reduce the sounds?