Sound and Vibrations 2: Make Sprinkles Dance
Can you make something move by using only sound? Your students will find out in this lesson plan as they explore the connection between sound and vibrations.
This is the second in a pair of lessons about sound. See Sound and Vibrations 1: Rubber Band Guitar for the first lesson.
- Understand that sound can cause materials to vibrate.
- Demonstrate how you can make something move using sound.
NGSS AlignmentThis lesson helps students prepare for these Next Generation Science Standards Performance Expectations:
- 1-PS4-1. Plan and conduct investigations to provide evidence that vibrating materials can make sound and that sound can make materials vibrate.
|Science & Engineering Practices||Disciplinary Core Ideas||Crosscutting Concepts|
|Science & Engineering Practices||Planning and Carrying Out Investigations.
Plan and conduct investigations collaboratively to produce evidence to answer a question.
||Disciplinary Core Ideas||PS4.A: Wave Properties. Sound can make matter vibrate, and vibrating matter can make sound.
||Crosscutting Concepts||Cause and Effect.
Simple tests can be designed to gather evidence to support or refute student ideas about causes.
Each group will need:
- Small cup, bowl, or food storage container
- Piece of plastic cling wrap, larger than the opening of the container
- Rubber band that fits tightly around the perimeter of the container
- Pinch of granular material like salt, sugar, or small sprinkles (colored sprinkles will be the easiest to see on the clear plastic wrap)
- Cafeteria tray or large plate
You will also need damp paper towels for clean-up.
Background Information for TeachersThis section contains a quick review for teachers of the science and concepts covered in this lesson.
The background section of the first lesson plan in this series explains how vibrating materials create sounds. However, the reverse is also true: sound can make materials vibrate. You might have noticed this if you've ever been to a concert, or in a car with the stereo cranked up all the way. The music can get so loud that you can actually feel the ground or your seat vibrating. Vibrations from the air molecules are transferred to the solid objects strongly enough that we can feel them. Of course, loud sounds like that can damage your hearing, so in this project your students will explore something a little safer.
The fact that sound can make materials vibrate also explains how our ears work. Vibrations from air molecules are transferred to our eardrum, a thin membrane inside our ear (Figure 1). The vibrations of the eardrum are converted into nerve signals, which are sent to the brain, allowing us to hear the sound. Our ears are very sensitive, so even soft sounds like a whisper still cause the eardrum to vibrate.
When sound waves enter a human ear they travel past the outer ear until they hit the ear drum. The ear drum vibrates air trapped in the inner ear and a nerve sends a signal to the brain which can decipher the vibrations as different sounds.
Figure 1. Simplified diagram of vibrating air molecules causing the ear drum to vibrate.
In this project, your students will use a thin membrane made from plastic wrap stretched over the opening of a cup. If you put your face very close to the membrane and hum, you can make it vibrate. These vibrations can be hard to see on their own, however. To make them easier to visualize, you can sprinkle some granular material (like sugar, salt, or sprinkles) on top of the membrane first. Then you will see them jump and "dance" around as the membrane vibrates.