Do you Hear What I Hear?: Exploring the Structure and Function of the Ear

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Objective

Students will explain how sounds waves are processed by the ear and nervous system.

Big Idea

The ear is a specialized organ with variety of moving parts that capitalize on sound wave movement to process the audible environment through sensory nerves.

Introduction

Lesson Background & Justification:

   The ear is an organ that detects sound that also aids in balance and position of a person. The ear is part of the auditory system and is comprised of three functional units; the inner, middle and outer ear that work cooperatively to receive, funnel and transform sound waves into electro-chemical impulses from the external world. Mechanoreceptors known as hair cells that line the inner ear in particular are responsible for hearing when they are stimulated and release a chemical neurotransmitter that is transmitted along the spiral ganglion which sends information through the auditory portion of the vestibulocochlear nerve (the conduit from the inner ear to the brain) to the temporal lobe of the brain. In this lesson, students learn to identify the locale and function of the ear's anatomical parts in the effort to establish both a visual and contextual foundation needed to comprehend the physiology of this organ. Command of this content aids in the student's ability to exemplify the biological theme of form and function and grows their appreciation in the idea of cellular, tissue and organ specialization in organisms.  

Essential Prior Knowledge: Prior to experiencing this lesson, students should be familiar with the following content/concepts:

             a) Structure and Function of Neurons  

            b) Organization/Hierarchy of organisms

            c) Afferent and Efferent Cells 

Lesson Preparations:

 In the effort to prepare for this lesson, I make certain that I have the following items in place: 

a) A class set of the Charting Audiograms Student WorksheetStudent Worksheet Audiogram Graph and Extension activity worksheet (see attachment). (One set of sheets per student)

b) A class set of rulers, glue or tape, receipt paper and scissors.

c) Student lab books.

Common Core and NGSS Standards:

HS-LS1-2- Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

SP2- Developing and Using Models.

MS-LS1-8- Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior or storage as memories. 

SP4- Analyzing and Interpreting Data

Standards Rationale:

      In the science classroom, students are regularly charged with tasks to collect and make sense of data from readings and investigations. What makes these science experiences powerful enough to retain however, is an instructor's ability to access, stimulate and develop students' higher order thinking capacities for cognitive growth and subsequently establishing sound learning practices. In this lesson, students learn to argue the validity of a scientific claim through scientific investigation, data collection and analysis therein. This aforementioned skill set is essential to science lessons because they offer students an opportunity to systematically approach everyday claims, the basis of science. It also establishes a framework for students to handle open inquiry and use evidence as support of claims made within their future investigations.  Furthermore, students learn to extract and develop significance of data collected within this framework with the aid of graphic organizers and are better suited to think critically about their work as a final result. 

Engage

10 minutes

Section Sequence:

      In this section of the lesson, my goal is to motivate students understand to extract the  subliminal messages embedded within the commercial advertising of a popular headphone set; Beats by Dre. The idea is to empower them to consider factors of the technology that aren't overtly pronounced and how overriding this with a more positive overtone can be a detriment to the consumer in some form or fashion. In this case, the potential loss of hearing.  This activity proceeds as follows:

a)Slide 1- Ask students the list of question in the top to bottom progression on the slide. After question #2, play the following video and then address the question. 

b) If the discussion of potential hearing loss is not mentioned in students responses for question 3, provide prompts (eg. How can this impact hearing with excessive wear?) that will avail students to the idea. 

Explore

30 minutes

Section Primer:

     An audiologist is a health-care professional specializing in identifying, diagnosing, treating and monitoring disorders of the auditory and vestibular system portions of the ear. Audiologists are trained to diagnose, manage and/or treat hearing, tinnitus, or balance problems. To assess their patients, they use hearing tests which are evaluations of the sensitivity of a person's sense of hearing and are most often performed to determine a person's hearing sensitivity at different frequencies (property of sound that most determines pitch and is measured in hertz (Hz)). In this section of the lesson, students loosely evaluate their sensitivity to various frequencies. 

Section Sequence:

a) Slide 2: Read step a to the class and click on the following link to project the statistics: Department of Defense Hearing Center of Excellence 

b) Progress with the directions as prescribed on the slide. However, take the time to promote a class discussion for each question and allow students to suggest the structure of the experiment using the resource linked in step e (video below) once they group arrives to step d. The general order of the investigation (Investigation question-> Steps -> Data collection-> Data Analysis & Interpretation) should be recorded in student lab books. Emphasize the importance of repeated trials so that students can produce a sound investigation and collect decent data.  

c) Discuss trends and consistencies in data trials post investigation and direct students to the diagram on the left which references the the maximum loudness of Beats by Dre technologies. Add to the discussion. How can this impact someone's hearing and how would one fair on the hearing test over time after daily exposure to the technology.   

Standards Covered:

SP4- Analyzing and Interpreting Data

Explain

15 minutes

Section Sequence:

      In this section of the lesson, my goal is to provide students with adequate content that helps to explain how sound is processed in humans. In doing so, students will be able to rectify the idea and association of hearing loss to the constant exposure to loud noises such as those availed in ear buds or headphone sets. This section proceeds as follows:

a) Slide 3: Engage students in a light discussion (general Q and A) using the question prompts that appear at the top of the slide. 

b) Share with students that they will produce a visual (foldable) that can be used for future reference to help them to remember how sound is processed. Using the image of image on the screen, and the directions seen here Scholastic Ear Foldable, instruct students to illustrate and label the 3 major parts of the ear in an extended fashion on the receipt tape. Share that the extra room will provide space for them take notes using the following video:

     

c) Ask- What molecular events are important in order for the brain to receive the message from the ear? Discuss neurotransmission. 

d) Slide 4- Show and explain the general events of action potential and neurotransmission using the image to the left. Then play the following video Inner Hair Dancing to show how actual hair cells seen at the top of the illustration respond to music. 

e) Finally, display the illustration to the right, discuss the intricacies of mechnotransmission in the cochlea and instruct students to record the details on their foldables. 

Standards Covered:

HS-LS1-2- Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

SP2- Developing and Using Models.

MS-LS1-8- Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior or storage as memories. 

SP4- Analyzing and Interpreting Data

Extend

25 minutes

Section Primer:

       An audiogram is a graph showing the results of the pure-tone hearing tests. It illustrates the type, degree, and configuration of hearing loss. The frequency or pitch of the sound is referred to in Hertz (Hz) and is located on the y axis. The intensity or loudness of the sound is measured in decibels (dB) and is located on the x axis. In this section of the lesson, students learn to construct & interpret an audiogram as a funciton of damage to the hair cells in the ear.

Section Sequence:

a) Provide students with a copy of the  Student Worksheet Audiogram Graph and Extension Activity Handout (attached). 

b) Introduce the term audiogram to students and explain the significance of its data. Proceed with the instructions as they appear on the slide. For step 2, use the following video for students to decorate/detail their blank audiograms. 

     

Standards Covered:

SP2- Developing and Using Models.

SP4- Analyzing and Interpreting Data

Evaluate

10 minutes

Section Sequence:

       In this section of the lesson, my goal is to provide students with problem based assessment for them to reflect on how external pressures can alter the internal machinery of the ear and consequently its physiology. Students use excerpts from an article that explains the phenomena of ears popping on a plane to deduce and/or target the lost of function of one its parts. This activity proceeds as follows:

Slide 6: Distribute copies of the exit tickets to students and proceed with directions as seen on the slide. 

Standards Covered:

HS-LS1-2- Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

MS-LS1-8- Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior or storage as memories.