Medicine Chapter 1: Hearing

Chapter Challenge
The high school principal is concerned about loud music at an upcoming dance. Students are challenged to either convince him to schedule the dance or support his contention that the music at the dance will have a negative impact on students' hearing. They are to write a paper stating their position, and explain why a dance should or should not be held with all opinions justified by scientific facts and examples.

Chapter Summary
To gain knowledge and understanding of physics principles necessary to meet this challenge, students work collaboratively on activities in which they investigate sound waves and hearing. These experiences engage students in the content from the National Science Education Standards.

Activity Summaries

Physics Principles

Activity One: Measuring Sound Levels

Students are introduced to the decibel scale by using a sound level meter to measure the decibel level of different sounds. They read about the relationship of hearing loss to age and to noise levels.

• Decibel scale
• Sound waves

Activity Two: Learning More About Decibels

In this activity, students control variables in an experiment that enables them to collect and compare data as they increase the intensity of the sound. They learn about the decibel scale itself, then to interpret the scale with a logarithm graph.

• Decibel scale
• Sound intensity
• Sound conduction

Activity Three: Rock Music and Earplugs

Using a model that simulates sound conduction in the head, students measure dB levels of music heard through and close by headphones. They compare this to appliances' dB levels and legal limits for dB exposure.

• Frequency, period, and pitch
• Periodic sounds
• Decibel levels

Activity Four: Frequency and Pitch

Students generate sounds, noting differences between frequency and period. Observing motion of vibrating meter sticks enables them to relate pitch to frequency, and describe the differences.

• Sound waves
• Waveforms
• Amplitude
• Hertz

Activity Five: Measuring and Displaying Waveforms

Students use an oscilloscope to study wave patterns of different sounds. They learn to observe differences in the period and amplitude of the wave patterns for sounds with different pitches and frequencies. Reading about sine waves introduces the concept of harmonics.

• Decibel scale
• Frequency response

Activity Six: Frequency Response Curves

Students use a sound meter to collect data for sounds generated by an oscillator or keyboard. They plot the collected data on log paper enabling them to compare the decibel level of sounds with different frequencies. This introduces them to the concept of frequency response.

• Human hearing

Activity Seven: The Ear

A simulation with resonating tubes enables students to approximate frequency response of the ear. They connect their results back to the challenge by reading to learn more about how the tubes and bones in the ear work together to transfer sound waves to the inner ear.

• Sound conduction
• Resonance

Activity Eight: The Middle Ear

To develop a deeper understanding of hearing, students focus on the bones in the middle ear. They read to learn about how these three bones use force and pressure to amplify sound waves before they reach the inner ear.

• Force and air pressure
• Sound conduction
• Amplification of sound waves

Activity Nine: Tooth Tunes: The Inner Ear and Transducers

Students construct a transducer to demonstrate how sound waves are conducted through the ear. Comparing this to a microphone helps students understand how waves are transformed into sound.

• Sound conduction
• Energy transformation

Activity Ten: Your Hearing Curve

Students measure frequency response in their own ears. Then to prepare for the challenge, they read more about hearing loss and hearing aids.

• Human hearing
• Decibel scale
• Frequency response