Piezoelectric Materials Lesson

Piezoelectric at a glance

Background

Ever wonder how pressing a button can make something light up or how tiny speakers in your headphones produce sound? The answer lies in piezoelectric materials! In this lesson, students will explore how certain materials, like quartz and barium titanate, can generate electricity just by being squeezed or pressed. This is called the piezoelectric effect.

Students will learn that this effect works both ways—when you apply a voltage to a piezoelectric material, it changes shape slightly, which is how speakers in greeting cards or headphones create sound. By vibrating at specific frequencies, these materials produce the sounds we hear every day.

Through hands-on activities, students will get to see how piezoelectric materials work and understand why they are so important in modern electronics. From tiny sensors to powerful amplifiers, these materials are everywhere, helping to make our devices smaller and more efficient.

Lesson Objective

Students will explore the piezoelectric effect, a phenomenon where certain materials generate an electric charge in response to mechanical stress. By experimenting with ceramic disks and polymer films, they will observe how these materials produce electrical signals and light up LEDs when subjected to pressure.

Experiment Description

In this experiment, students will apply pressure to piezoelectric ceramic disks and polymer films and observe the resulting electrical activity by lighting up LEDs. They will test different levels of force and bending to see how these materials convert mechanical stress into visible light and understand the underlying principles of the piezoelectric effect.

Materials List

2 piezoelectric ceramic disks
2 piezoelectric polymer films
4 LEDs
8 alligator clip sets
Musical greeting card (optional)
Voltmeter (optional)

Safety Precautions

Avoid applying excessive force to the piezoelectric materials to prevent permanent damage.
Ensure the room is dark enough to see the LED lights clearly and handle all electrical components with care.

The Experiment

1. Test both piezoelectric materials prior to starting the demonstration to make sure neither is damaged or needs to be replaced.

2. Connect one LED to a piezoelectric polymer film so that the long wire of the LED is connected to one leg of the piezoelectric material, and the short wire on the LED is connected to the other leg of the piezoelectric film. Use the supplied alligator clips to make these connections.

3. Connect 1 LED to a piezoelectric ceramic disc so that the long wire of the LED is connected to the red wire coming from the disk and the other wire of the LED is connected to the black wire of the disk.

4. With a very light tap, slowly increase the force until the LED visibly flashes with each tap. Show effect to students. It is important to simply tap the disk and to not apply steady pressure. NOTE: The room must be fairly dark to see the LED light.

5. Bend the polymer film back and forth slowly. Increase the speed at which you are bending the material until the LED lights up with each bending motion.

6. Open the musical greeting card and explain the use of piezoelectric materials as a speaker. Take apart the card so that students can see the actual piezoelectric “buzzer.” Supply students with the background information on piezoelectric materials.