Elementary School Science

Input:
What is the most important content in this lesson?
To reach the lesson’s objectives, the students need to understand:

• The function of each part of the ear.

• The role of the eardrum and how sounds vibrate when passing through the eardrum into the inner ear and then to the brain for understanding.

• Different types of ear problems and how they affect a person’s hearing.

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How will the learning of this content be facilitated?

• The lesson will start out with the students sitting at their desks. The teacher will have the following objects on a desk in front: drum, bell, CD player or iPod, feather, and eraser. The teacher will ask the students which object will create the loudest sound and which will create the softest sound. The demonstration should last for about 10 minutes.

• The teacher will lead a class discussion about the activity, asking questions about what the students observed. The teacher should ask the students what made each object produce the sound it did. For example, a feather is very light and doesn’t make much noise because of the material it is made out of. A drum, however, is loud because the material is harder/ the object is hollow inside.

• After the discussion, the teacher will hand out the “Diagram of the Human Ear” worksheet. If it is possible, project the “Diagram of the Human Ear” onto the board using a projector or put into a PowerPoint document and project so that the teacher can point to the parts of the ear while they explain. Students should write the name of each part on the line as it is explained. From this activity, the students will learn about the parts of the ear. Each part’s function will be explained. 

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Parts of the Ear and Their Functions:

• Outer Ear: has three sections:

• Pinna: the outside of the ear (point to your ear to give more of a visual for the students); helps to gather sounds and vibrations.

• Ear Canal: a non-visible (unless using an otoscope/ device for looking inside the ear) tube. The sound travels down this tube to reach the tympanic membrane or eardrum.

• Tympanic Membrane (Eardrum): a very thin, fragile sheet that separates your outer and middle ear. The eardrum vibrates when sound hits it.

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• Middle Ear: mainly filled with air and contains three bones:

• Malleus (Hammer), Incus (Anvil), and Stapes (Stirrup)

• These bones help to amplify sound and transfer it form air to fluid.

• The stapes is the smallest bone in the body.

• **Explain that the words in parentheses (hammer, anvil, stirrup) are used to describe the shape of each bone**

 

• Inner Ear: mainly filled with fluid and contains the cochlea. The cochlea is the organ of hearing and takes the vibrations and translates them into electrical signals. Tiny hairs called cilia help to translate the signals as well. These signals travel along the auditory nerve to reach the brain for understanding.

• Elliptical/ Oval Window: located between the middle ear and the inner ear.

• Circular Window: located between the middle ear and the inner ear.

• Vestibular Nerve: helps transmit electrical messages to the brain.

• Tympanic Cavity: surrounds the malleus, incus, and stapes.

• Eustachian Tube: helps equalize pressure in your ears.

 

• (Information source: http://www.ducksters.com/science/hearing_and_the_ear.php)

• Explain to the students that loud sounds have high volume and soft sounds have low volume. Ask them what they know about volume (for example, they turn up the volume on their TVs or radios to hear the sound better). Explain that volume is measured in decibels (dB).  The lower the number of the decibel, the softer the sound. The higher the number of the decibel, the louder the sound. Explain that volume is created by sound waves. Sounds that are loud have sound waves that have a greater amplitude or height. Sounds that are soft have sound waves that have shorter amplitude. Objects that are loud—such as sirens, fireworks, and chainsaws—use a lot of energy to create their sound. The sound waves of these objects are larger and that is what creates the loud sound. It is important to stress that the ear is very sensitive. Certain numbers are harmful for your ears and should be avoided Listening to loud sounds is okay once in a while, however, over time the cilia (hairs in your inner ear) will become damaged. Once the cilia are damaged, they can never be repaired.

• After the diagram is explained, the students will break into groups of three. The students will work on an activity called “Sounds We Can Hear”. This activity will help to explain the decibel scale and show the students what objects are “safe sounds” and what objects are “harmful sounds”. Each student will be given a “Sounds We Can Hear” worksheet. Each group will be given a sheet with pictures of different objects. The students will need to work together to determine where on the decibel scale the object belongs.  Review all the pictures first, ensuring the students know what the objects are. Allow the students to work for about 10-15 minutes. Reconvene and discuss the answers when the students are finished.

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• 10 dB = whisper

• 20 dB = leaves

• 50 dB = talking

• 70 dB = vacuum

• 100 dB = lawn mower

• 120 dB = chainsaw

• 150 dB = airplane takeoff

• 160 dB = rocket

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• The final assessment will be for the students to answer the question; "Think about what we learned today in class. Why is the decibel scale important? What are the characteristics of the objects found at the top of the decibel scale? Once cilia are damaged, they can never be repaired and hearing can be affected. What problems would you face if you couldn’t hear well?"