Present an overview of how hearing happens. Use pictures and diagrams of the ears to help students visualize the concepts. Introduce the concept of decibels, a measure of loudness, by asking children what sounds they hear every day and telling them how many decibels each activity produces. For example, if a child responds that they talk to their friends, then you can tell them that talking normally is about 50 decibels.
Play sound clips of loud noises (above 85 decibels) such as an electric drill, a garbage truck and a police siren. Show students how the decibel levels of those activities compares to normal daily activities. Point out that, without ear protection, any sound louder than 85 decibels is harmful to hearing.
Ask students to put on stereo headphones and play the music at the very lowest level. Demonstrate the decibel level in the headphones by making sounds (such as whispering, talking at a normal level and turning on a vacuum cleaner) and asking students to turn the volume up until they can no longer hear you.
Show students pictures of several sound sources (such as a busy road, a lawn mower, an airplane and rainfall). Ask them to put the sounds in order according to how loud each is. Ask for which sounds you need to wear hearing protection.