The Science of Sound
Buzz, crackle, bang — sound is everywhere! Use these fun activities to help students discover how sound travels and how our ears pick it up.
- Grades: 6–8, 9–12
Start off your unit by looking at words that imitate the sounds they represent, such as hiss, rustle, growl, and chirp. This onomatopoeia enriches language, allowing us to capture sound in writing. After sharing some examples with students, ask, “What do these sound words mean to you? How do they make you feel? Excited? Annoyed? Happy?” Invite students to brainstorm as many sound words as they can think of. Encourage them to name sounds which are pleasant to them (and why), and which are unpleasant, and record these on a T-chart.
Hearing allows us to communicate with others and to navigate our world. Invite students to experience a heightened awareness of all the important sounds around them with a sound walk through several areas of your school, such as the hallway, cafeteria, library, and playground. Ask students to pay attention to all the different sounds they hear along the way. Then have members of the class compare their experiences. What different sounds did each person hear along your journey? Next, have pairs of students take turns observing the sounds in different areas of your classroom or school more closely. Ask one student in each pair — “the listener” — to close his or her eyes (or put on a blindfold) and describe all the sounds that he or she hears to the other student, who will record them. (You may want to monitor blindfolded students closely, or ask student pairs to choose a location and sit before the listener is blindfolded.) Encourage students to use rich, descriptive language in their observations. After everyone has been a listener, ask students to write short stories inspired by — and including — at least five of the different sounds they experienced.
Sign Language Challenge
Many people that have hearing loss or are deaf are not able to communicate by speaking, since humans usually learn to speak by imitating the sound of the words they hear. However, some hearing-impaired people learn to speak by reading lips, and imitating the way our mouths move when we speak. Other hearing-impaired people learn to "speak" with hand gestures. This is known as sign language. Invite students to visit www.Aasdweb.com, a searchable sign language database and dictionary. Share with students some of the pictures and video clips showing signs in action; then challenge each student to learn — and teach to the class— a short message in sign language. To extend this activity, try teaching a short lesson using only signs!
This fun, interactive game is a great way to liven up your sound science unit — and reinforce good listening skills. Begin by compiling a selection of different sounds from sound effects and nature CDs, available at the public library. You can also find specific sounds free online at www.findsounds.com. Next, arrange the sound selections into categories, such as farm animals, sea creatures, transportation, or musical instruments. Divide the class into at least three groups. Then challenge students from each group to take turns choosing a category and a point value, and trying to guess what each specific sound is. Encourage them to respond in true Jeopardy style by posing their answer in the form of a question, such as “What is a puffer fish?”
How is sound actually made? By vibrations, moving in waves to our ears! Illustrate this concept for students with a simple experiment. Loosely stretch a rubber band between your thumb and forefinger, and ask students to predict what will happen when you pluck it. Then have students try plucking their own rubber bands and recording the results. Ask, “What did you observe?” Students should discover that a plucked rubber band vibrates when plucked, thereby making a sound. Encourage students to experiment with their rubber bands to try to produce different kinds of sounds. To extend, challenge students to find other ways to demonstrate the vibration of sound, such as strumming a ruler with one end held firmly against the edge of a desk.
Waves of Sound
Extend your students´ understanding of sound waves with this simple experiment. Cover a bowl wih plastic sandwich wrap. Pull the plastic tight across the top in all directions until it is flat and smooth. Use a rubber band to secure the plastic wrap securely. Then sprinkle some pepper onto the plastic — and make some noise! Hold a pot and spoon near the bowl and hit the bottom of the pot hard. What do students see? Explain that the loud noise you made is a vibration, which gets transmitted through the air, to the plastic. The plastic vibrates, and makes the pepper dance. Invite students to try this experiment for themselves.
The Parts of the Ear (Using the Reproducible)
Give students an inside view of how we hear with the Parts of the Ear Reproducible, below. Label each of the parts together as a class, or ask students to work independently, guided by books or Web sites (see "Sound Science Resources," above). To extend, have small groups of students each research and create a presentation on a part of the ear in greater depth.
Parts-of-the-Ear Role Play
Invite students to learn about the parts of the ear and how they help us hear with this exciting role-playing activity. To begin, assign each part of the ear to a different student or small group. Give each student a sign or armband to wear with the name (and perhaps a picture) of his or her “ear role.” Once students have practiced their roles, challenge them to put the whole thing into motion. Begin with the first student saying a message, such as “Hello!” Then have each part of the ear move accordingly, as shown above, to pass the message to the “brain,” who receives and repeats the message.
Amp Up the Sound!
The loudness of sound, or its amplitude, is measured using the decibel. Small differences in amplitude (short sound waves) make quiet sounds, while large differences (tall sound waves) make loud sounds. Share with students the “How Loud Is That?” decibel chart, above, then try this fun demonstration. Cover a radio speaker with a sheet of paper, and sprinkle uncooked grains of rice on top. Turn the radio on and have students observe the rice. Next, crank up the music all the way — and watch out for flying rice! Based on what they observed, ask students to compare this experiment with the sound wave experiment above. Then ask: “What relationship exits between the loudness of sound and amplitude?” (The bigger the amplitude, the taller the sound waves, and, therefore, the more rice will jump off the paper.) To extend, tell students: “Some sounds have so much amplitude, they can damage our ears!” Have them further investigate decibel levels (starting with the links in "Sound Science Resources," above), then design hearing safety posters to share their findings with the class.
Pitch and Frequency
Ask students to place their fingers on their throats where there is a bulge, and say “Aaahhhhh.” Can they feel the vibration? Explain that when a person speaks, two strips of muscles called vocal cords come together, causing the air from our lungs to vibrate. Have students practice making different sounds by lengthening and relaxing their vocal cords (for a deeper, “lower” voice) or shortening and tensing their vocal cords (for a “higher” voice). As giggles ensue, relate what the kids just experienced to the vocabulary from the "Sound Science Glossary," above. For example, pitch — how “high” or “low” a sound is — is measured by frequency. When you speak in a low-pitched voice, the vocal cords vibrate air more slowly — at a lower frequency — than when you speak in a high-pitched voice. Share with students some examples of the different sounds from the “High-Pitched or Low-Pitched?” chart, above. Then ask students to research the different frequencies of some additional sounds and add to the chart.
Out of Our Range
Every minute of every day, we hear sounds. Many of these are made by animals we hear birds calling, dogs barking, and bees buzzing. However, we actually are hearing only some of the noises that the animals of the world can make. Many animals have special abilities to both generate and hear sounds that are either too high-pitched or too low-pitched for humans to hear. Do students know any of these animals? After students have guessed, share with them the "Animal-Sound Frequencies" chart. Then challenge them to name why they think each animal has these special abilities.
Many animals make and use sounds for specific purposes, such as "talking" to others of their own kind. They call to each other to find mates, to warn of approaching danger, and to keep in touch when they cannot see each other. Animals also make sound to find prey. For example, spiders and sharks use sound to listen for their prey; spiders can hear the beating of insect wings, while sharks can hear a fish´s muscles as it swims. On the other hand, bats and whales find prey by sending out streams of very high-pitched sounds, then listening to the echoes of these sounds. Once you have shared some of this information with students, invite them to choose an animal and research the sounds it makes. Encourage students to enhance their presentations to the class with sound recordings of their chosen animals, which can be found at www.findsounds.com, http://dkd.net/whales/wsounds.html and www.oceanmammalinst.org/songs.htm.
Amazing Animal Ears
Most mammals have pinnae — exterior ears — for gathering and funneling sound inward. We know that the placement and mobility of ears affect sound how sound is gathered. Demonstrate this to students with a fun classroom demonstration. Invite students to create their own animal-ears headbands using the template reproducibles below. Show students how to trace the various “Ears” onto felt material, then glue the two halves together and attach to a headband. To make a hippo- or rabbit-ear headband, attach felt ears to the top of headband; for a frog- or elephant-ear headband, attach ears on either side. As the class sports its new “ears,” share with student´s some of the information in "Fun Animal Sound Facts." You might also challenge students to role play hearing the sounds as the animals do, by moving the ears, head, and their bodies accordingly. For reference, check out: www.learn.co.uk/glearning/primary/lessons/ks1/sounds2/article.asp.