Seeing with Sound
How do blind people get around safely? Some people use special guide dogs. A well-trained dog knows A____ cross busy streets and get from place to place. Some people use long white canes to help them get around.
Guide dogs and canes are helpful, but is there a better way B____? A scientist in England thought so. He is a zoologist named Dean Waters who studies bats. He knows that bats are able to fly in the dark without bumping into things. Also, he knows that bats go by using sound to "see". Dr. Waters wondered C____.
Bats as they fly make squeaking or clicking sounds. These sounds travel outward in waves. When the waves hit an object such as a tree or a house, they echo, or bounce back. The waves travel back to the bat's ears. From the echoes, a bat learns the location and shape of objects around it. This is called echolocation.
Dr. Waters talked to other scientists, including Deborah Withington and Brian Hoyle. They all worked together and invented a new kind of cane. At first they called it a "bat cane" because the idea started with bats. The new cane has a computer in the handle. It sends out high sounds D____. The sound waves bounce off objects and echo back. This causes buttons in the handle to buzz. With a little training, a person E____ can tell where the objects are and can "see" with sound!