Exploring the Connection Between Vibrations and Sound
Did you know that you can use science activities to help students improve their writing skills? By incorporating a science notebook or journal, students can record their observations and thoughts. For instance, have you ever wondered what happens when you release a ruler? Well, it actually vibrates and produces a sound. Interestingly, the amount of the ruler hanging off the edge affects the pitch of the sound. The more ruler that extends beyond the table’s edge, the lower the pitch, while less extension results in a higher pitch. It might be helpful to review the concept of pitch prior to conducting this experiment.
One of the key takeaways from this activity is that vibrations generate sound. Encourage students to brainstorm other examples that demonstrate this relationship. It could be as simple as stretching a rubber band between two fingers and plucking it (note: goggles are necessary for safety). When the rubber band is plucked, it vibrates and creates a sound. If any of your students play a musical instrument, they can also relate to this concept. When a string on an acoustic guitar is plucked, the vibration of the string is transferred to the wooden body of the guitar. As a result, the wooden body, with its larger surface area, pushes more air molecules and generates sound.
We often take for granted the fact that our voices also rely on vibrations. Inside our throats, there are folds of tissue known as vocal cords (although “vocal folds” is a more accurate term). When we speak or sing, these vocal folds vibrate, creating sound. To explore this firsthand, have your students place their fingers on their throats while humming a low-pitched tone. They will be able to feel the vibrations. It’s worth noting that the size of vocal folds differs between men and women. Adult males typically have longer and thicker vocal folds, resulting in lower-pitched voices. On the other hand, children have much shorter vocal folds, allowing for faster vibrations and higher-pitched voices. Just like with a guitar, we can control the pitch of our voice by adjusting the tightness of our vocal folds. The tighter they are, the higher the pitch.
To further investigate the relationship between tightness and pitch, you can conduct a simple experiment using a stretched rubber band (refer to Figure 2). While one student plucks the rubber band, another student can adjust the tightness by varying the amount it is stretched. By altering the tightness, the pitch of the sound can be changed. The more tightly the rubber band is stretched, the higher the pitch as it vibrates at a faster rate.
When it comes to teaching science concepts, it’s important to engage students through hands-on activities. By linking vibrations and sound, students can discover the fascinating connection between these two phenomena. So why not give it a try and let your students explore the world of vibrations and sound for themselves?