Lesson Five: How is sound like waves? How do animals echolocate?

Introduction:

The molecules in matter vibrate when something makes a sound. The vibrations are called sound waves. Sound waves move from one molecule to another as they pass through matter. Bats have an excellent sense of hearing. They can hear high pitched sounds that are out of our range of hearing. Bats use this ability to find their way around in dark caves. When a bat makes a high pitched sound it bounces off the wall of a cave as an ultrasound echo. The bat can tell how far away the wall is based on the time that it took between the sound being made and returning as an echo. A dolphin can also use clicks to echolocate things. A dolphin makes a clicking noise and when the sound bounces and echoes off an object it travels back to the dolphin to its lower jam, then to its ear, and finally to its brain. The brain is able to distinguish the objects shape, size and location through echolocation. Dolphins can distinguish between different materials such as tin or aluminum cans, live or dead fish and items as small as a pea.

Learning Outcomes:

The learner will use two models (a moving toy slinky and by dropping an object in water) to demonstrate how sound waves occur. The learner will infer how sound waves travel out from a source and weaken as they spread. The learner will demonstrate how sound echoes off of objects. The learner will show how animals use echolocation to understand their surroundings.

Curriculum Alignment:

National Science Education Standards

Content Standard A: Abilities necessary to do scientific inquiry

• Understanding about scientific inquiry.
• Employ simple equipment and tools to gather data and extend the senses.

Content Standard B: Physical Science

• Position and motion of objects
• Sound is produced by vibrating objects. The pitch of the sound can be varied by changing the rate of vibration.

Content Standard C: Life Science

• The characteristics of organisms
• Organisms and their environments

Content Standard E: Science and Technology

• Abilities of technological design
• Understanding about science and technology
• Abilities to distinguish between natural objects and objects made by humans.

Content Standard F: Science in Personal and Social Perspectives

• Characteristics and changes in populations
• Changes in environments

Content Standard G: History and Nature of Science

• Science as a human endeavor

NCSCOS Music Objectives

Goal 6: The learner will listen to, analyze, and describe music. (National Standard 6)

• 6.02 Demonstrate perceptual skills by conducting, moving, answering questions about, and describing aural music examples of various styles and cultures.
• 6.03 Use appropriate terminology in explaining music, music notation, music instruments and voices, and music performances.
• 6.04 Identify visually and aurally a variety of instruments including many orchestra and band instruments, and instruments from various cultures.

Goal 8: The learner will understand relationships between music, the other arts, and content areas outside the arts. (National Standard 8)

• 8.01 Identify similarities and differences in the meanings of common terms used in the other arts.
• 8.02 Identify ways in which the principles and subject matter of other content areas taught in the school are related to those of music.

Goal 9: The learner will understand music in relation to history and culture. (National Standard 9)

• 9.01 Identify the style or genre of aural music examples from various historical periods and cultures.
• 9.02 Describe in simple terms how elements of music are used in music examples from various cultures in the world, past and present.
• 9.03 Identify various uses of music, and describe characteristics that make certain music suitable for each use.
• 9.05 Show respect for music from various cultures and historical periods.

Time:

One 60 minute period

Materials:

• Slinky
• Water
• Marbles
• Bowls
• Garden hose (or similar tubing such as connected drinking straws)

Technology Resources:

5E

Engage:

Play examples from the Wildmusic website which represent frequency of animal communication. Allow students to identify when they start hearing sound and when the sound has ended. Play examples of varying human cultures to peak student awareness of sound and distance. Listen to examples of African drumming. Relate how drums are used for communication in their culture. The largest drums sound waves travel the farthest. Listen to examples of whistles from Bolivia. Relate how whistles can be heard across their environment.

Explore:

Give each student pair a slinky. Have students stretch out the slinky and explore waves created in the slinky when it is compressed and stretched. Discuss with individual pairs how the wave pushes through each coil and makes it vibrate and also how the coil stops moving after the wave passes. Ask students how this might be similar to sound waves. Ask students what direction the wave is moving. They should say linear (left or right). Ask students if sound works that way and do we have to be directly in the line of sound to hear it? Give each student pair a small bowl of water and a marble. Ask students what will happen when they drop the marble in the water? Ask students what they will see and hear. Have students drop the marble in a large bowl of water. Discuss the rings they see. Ask students how this might be similar to sound?

Explain:

Discuss how sound waves move from one molecule to the next just like the wave moves from one coil to the next in the slinky. Discuss how sound does not only travel in one direction but spreads out. Have a student stand at the back of the room and whisper something to students at the front of the room. Discuss how it is hard to hear them because the sound waves spread out. Next stretch out a garden hose and have the same student whisper something into the hose while someone at the front holds the hose to their ear. (make sure the student doesn’t yell as it could hurt the listener’s ear) Discuss that you can hear through the hose because the hose keeps the sound waves from spreading out and becoming weaker. Connect several drinking straws together and whisperer into one end as a partner listens on the other side. Discuss how the sound waves travel through the straws.

Elaborate:

Ask students what happens when sound waves hit an object such as a wall. Discuss possibilities. Discuss what happens when a tennis ball hits a wall. What would happen if sound waves could bounce back like a ball? Have students go outside near the school or in an empty room and shout. The sound waves should bounce back in an echo. Discuss how some animals use echolocation to understand their surroundings.

Extend:

Have students explore acoustical spaces by encouraging them to sing in the bathroom, in the cafeteria and the gymnasium.

Evaluate:

Teacher observation

Vocabulary:

• Echolocation - the transmission of sound waves to locate objects
• Acoustics - interdisciplinary science that deals with the study of sound, ultrasound and infrasound

Websites:

www.wildmusic.org