1. Seung-ju Hong

2.  Introduction of bats
 Wave and Ultrasound
 Ultrasound used by bats

3.  Bats are the only mammal that can fly.
 The structure of bat’s body is different from bird structure of body.
 Bats are divided into two groups; micro bats and mega bats.
 Bats are nocturnal animal; they are active at night.
 Most bats cannot see at night. Therefore, they use echolocation producing
ultrasound, which allows bats to be active at night.
 Bats hunt small insects such as flies and they avoid obstacles by using
ultrasound.
 Bats are distributed all around the world except for north pole and south
pole.

4.  Wave is a disturbance that travels through material and accompanied by a transfer of
energy.
 The movement of ultrasound travels through a medium such as air.
 Ultrasound is a cyclic sound pressure wave with a frequency, which is greater than
human hearing.
 Bats can make 50~90 KHz (a unit of frequency) and hear the sound reflected that they
made.
 Frequency of bat’s ultrasound is directive; It is not absorbed even into the water.
 This enables bats to be active at night and catch insects in darkness.

5.  It is used for fish finder, echo-sounder and for the medical.
 An oscillator using piezoelectric effect of crystal flake
produces ultrasound.

6.  Bats use echolocation, biological frequency, in order to make
ultrasound.
 When bats emit ultrasound from their mouth, they can hear high
frequency that they make while flying; they listen to the vibration
that return from various objects near them.

7.  Bats use ultrasound for navigation.
 They catch flying insects in darkness while flying in full speed.
 Their sophisticated echolocation permits them to distinguish between a
moth and a falling leaf.

8.  http://www.scienceall.com/dictionary/dictionary.sca?to
do=scienceTermsView&classid=&articleid=254940&bbs
id=619&popissue
 http://en.wikipedia.org/wiki/Ultrasound
 http://www.wisegeek.com/what-are-bats.htm
 http://whatis.techtarget.com/definition/sound-wave
 http://wiki.answers.com/Q/How_do_bats_use_ultrasoun
d_to_navigate
 http://hyperphysics.phy-
astr.gsu.edu/hbase/sound/usound.html
 http://12-11.wikispaces.com/how+bats+fly
 http://terms.naver.com/entry.nhn?docId=426871&mob
ile&categoryId=1659
 http://www.bats.org.uk/pages/types_of_bats.html