Course Description

Did you say Grow your own microphone?

That’s right! This workshop series offers the opportunity to take part in a semester-long experiment where you will grow your very own, home-grown crystal transducer microphone. The weekly workshops will comprise one part laboratory experiment, one part cultural history class, and one part scientific analysis.

In 1880, two brothers in France, Jean-Jacques and Pierre Curie, along with Pierre’s wife Marie and their assistant Paul Langevin, extensively classified the properties of different crystals from around the world. One of the most striking discoveries they made was how some crystals, such as quartz, tourmaline, and Rochelle salt, would create sparks of electricity when they were agitated. This discovery, known as the piezoelectric effect, revealed how some of the simplest building blocks of matter in the world could become generators of huge charges of power.

Join us for this semester long workshop, follow the instructions closely, and you will finish this course not only with your very own, unique crystal transducer microphone, but with the knowledge to explain to your friends and family over the Christmas holidays, how amazing piezoelectricity is, and why it is one of sciences most incredible discoveries.

This optional elective course, run collaboratively between the Annenberg School for Communication, Penn Libraries, and the Department of Materials Science and Engineering, offers participants the opportunity to explore the piezoelectric effect and grow their very own piezoelectric transducer microphone.

Course Materials

• Articles and book chapters: PDFs and links to scholarly work, blogs, and press articles will be available on Canvas.
• Videos: Materials to watch and listen to will be available on Canvas.
• Laboratory materials: Materials and support will be provided by Penn Libraries at the Franklin Field Education Commons to complete the experiment.

Entry Requirements

• No prior knowledge or expertise is required to partake in this workshop.
• The course is structured around a live experiment, which will require a commitment to attending the workshops over the duration of the course.

Course Expectations

• You will need to be able to create a basic spreadsheet to log and monitor the progress of your crystal as it grows. (Assistance will be provided)
• Some simple math will be required to calculate ratios when preparing crystal solutions in relation to temperature during the growth phase. (Assistance will be provided)
• Preparation and class attendance are imperative.
• You will be responsible for working with lab equipment and tools, some of which may be mildly toxic and or could cause harm (pipettes, hot plates, chemical compounds, test tubes, beakers, jars, and liquids at high temperatures).
• Appropriate PPE, including gloves and goggles, will be provided.

Course Accommodations

• If you believe you need accommodations for a disability or a chronic medical condition, please visit the Student Disability Services website to learn more. You can contact Disability Services at the Weingarten Center in Stouffer Commons (Stouffer Commons, Suite 300, 3702 Spruce Street) to arrange an appointment to discuss your needs.
• Accessibility requests can be completed through the MyWeingartenCenter Student Portal.
•  As appropriate, the Disability Services office will issue students with documented disabilities or medical conditions a formal accommodations letter.
• Since accommodations require early planning and are not retroactive, please contact Student Disability Services as soon as possible.
• You are also welcome to contact me privately to discuss your academic needs. However, all disability-related accommodations must be arranged in advance through Disability Services.
• My priority is to facilitate a safe and respectful learning environment. I must consult with the Title IX Coordinator or a Deputy Title IX Coordinator upon a disclosure of an incident of sexual misconduct.
• For other questions about the course, please do not hesitate to contact me (even if you feel that you should “already know” something)!
• Please wait at least 24 hours for an email response on weekdays before following up, and EOD Monday for emails sent over the weekend.

Course Schedule

Week 1: What is a Piezoelectric Crystal

• History of Piezoelectric Crystals
• Outline of the workshop series

Week 2: Converting Sodium Bicarbonate to Sodium Carbonate

• Converting Sodium Bicarbonate to Sodium Carbonate

Week 3: Supersaturation

• Dissolving the base solution
• Supersaturating the solution
• Filtering the solution to produce seed crystals.

Week 4: Creating a metastable solution.

• Selecting your seed crystal
• Understanding metastasis, volume, and temperature.

Week 5: Observations

• Drop-in session to observe growth and document process.
• Calculate the process of experiments.

Week 6: Observations

• Drop-in session to observe growth and document process.
• Opportunity to repeat the process if things have gone wrong.
• Creative experiments with piezoelectric material

Week 7: Observations

• Drop-in session to observe growth and document process.
• Opportunity to repeat the process if things have gone wrong.
• Creative experiments with piezoelectric material

Week 8: Crystal Geometries, Understanding Axes, and Preparation for Wiring

• Understand how to identify the correct axis identification for the successful transmission of the piezoelectric effect.
• Observe growth and document the process.

Week 9: Visiting the Materials Engineering Laboratory

• Learn about axis identification using an X-ray particle beam detection machine.

Week 10: Removing Crystal from Supersaturated Solution

• Extraction, weight, and measurement of your piezoelectric crystal.

Week 11: Testing the crystal.

• Identifying the crystal geometry
• Testing the Piezoelectric Effect
• Shaping a bimorph piezoelectric crystal transducer

Week 12: Wiring

• Introduction to audio cable wiring and soldering.
• Wiring a bimorph piezoelectric crystal transducer.

Week 13: Resin Dip

• Creating a safe encasement for your piezoelectric microphone

Week 14: Testing Your Piezoelectric Microphone

• Congratulations, you’ve just made your very own DIY homegrown piezoelectric crystal transducer microphone.

Image: (right to left) Marie Curie, Pierre Curie, Henri Becquerel in the “hangar” at l’Ecole de physique et chimie industrielles in Paris, France (1898). Copyright © Wellcome Library, London Photographer unknown Available under Creative Commons Attr, CCBY 4.0