Introduce children to the idea of sound and how it travels. Tightly stretch plastic food wrap over a large bowl. The transparent wrap represents the eardrum. Lay a few uncooked grains of rice on top. Ask children to observe what happens when you stand next to the covered bowl and hit a cookie sheet. The loud noise causes the plastic wrap to vibrate by producing sound waves, which force the grains of rice to jump. Explain that the eardrum works in the same way and that it must be protected from excessive noise to avoid damage.
Use a simple diagram to illustrate the inner workings of the ear. Explain how the outer visible area collects sound and passes it through the ear canal, causing the eardrum to vibrate. The chain continues with the middle, then inner ear vibrating respectively. The extremely sensitive hairs in the inner ear trigger nerve signals that are received by the brain.
After they have studied the anatomy of the ear, explain how loud sounds can damage the hair cells inside the inner ear and lead to hearing problems. Discuss options to prevent this, such as wearing protective headphones or lowering the volume of music.
Print out coloring sheets and have children fill them in. Allow them to use any medium they like. Pick sheets that bear simple drawings that depict ways in which to protect hearing. Such messages as "turn it down" or "walk away" work well with young children. Be sure to discuss the ideas as the children color. Ask them whether they have ever been in situations where the sound was too loud and if so, what they did.
Make a noise chart to give children a visual idea of loud sounds -- and what is too loud. At the very bottom of the chart, write the words "voice whispering" and at the top write "firecracker booming." At regular intervals in between, fill in sounds, such as a chainsaw, emergency vehicle siren or regular talking voice. With research, you can give each sound a decibel level. Discuss with the children how much prolonged exposure to each of the sound levels could possibly damage the ears.