Object Lessons

Spring 2022

When it comes to everyday objects, engineers often have an uncommon fascination with the way things are designed and the reasons behind their utility. To get a glimpse into this unique way of thinking, we polled a variety of Johns Hopkins engineers and asked them to share their insights on a favorite object of their choosing. Their answers may surprise you.

Share your favorite objects with us, too!
Tag our social media accounts or use #JHUMyObject to submit your response and be featured on our Instagram stories.

Hoberman Sphere

Luo Gu, Assistant Professor, Department of Materials Science and Engineering

It’s not the best-engineered object, but it’s quite useful in my teaching and research. A Hoberman sphere is a transformable structure invented by Chuck Hoberman. It’s better known as a children’s toy nowadays. I first saw a Hoberman sphere in Chuck’s exhibition of his transformable architectural designs in Boston. Its transformation immediately reminded me of the swelling and dehydration of hydrogels, which are important biomaterials used in tissue engineering. Now I use a Hoberman sphere toy to teach the concept of hydrogel in my classes. Oh, and my version glows in the dark.




Marsha Wills-Karp, Chair of the Department of Environmental Health and Engineering

The humble battery plays a major role in my everyday life—from powering my alarm clock, which signals the start of my day, to powering my electric car to transport me to work. The first battery was made in 1800 by Alessandro Volta (the voltaic pile). Although improvements (rechargeable, longer life) have been made over time, they are still based on the simple concept of the conversion of chemical reactions to an electrical current. Hopefully, further improvements in battery life will make it possible to completely replace fossil-fueled cars, reducing greenhouse emissions, and saving the planet.



Gwendlyn Tsai Undergraduate Student, Department of Mechanical Engineering

The toaster is my favorite appliance in my apartment. As a mechanical engineer who focuses on thermofluids, I like it because it is a really simple example of how heat transfer is integrated into things we use every day. I also think there is something to be said about technologies that are so ubiquitous. It demonstrates that they fill a need with an elegant solution. It also doesn’t hurt that I love toast.



Paulette Clancy, Professor and Head of the Department of Chemical and Biomolecular Engineering

As I imbibe a nice glass of wine on a summer’s evening, I sometimes consider that this liquid is the product of fermentation and distillation and a tightly controlled separation processes to ensure safety and a reproducible product—all key components of a good chemical engineering background. By the way, winemaking involves a lot of water and energy use, which is something that wine companies are taking seriously for conservation purposes.



The best-engineered object I use in my daily life is small, portable, and cheap. It is a “thinking-aiding” device. There’s always room in my backpack for it, and it is extremely lightweight. The battery almost never runs out, and I can use it for months on end. In a matter of just a few seconds, it enables me to download some vague ideas I have in my mind, and through some not-yet-fully-understood process, it spits back these ideas at me in a better and clearer manner. Most people call this object a small paper notepad.

Jeremias Sulam, Assistant Professor, Department of Biomedical Engineering



I’m only an amateur woodworker, but I’d always been told the most important tool in a woodworker’s kit is their workbench, so a few years ago, I built mine, using mostly hand tools, over a period of one month. Since then, I’ve used it to remodel and improve the two homes it’s been in. I’ve built furniture and even wandered into motorcycle and car maintenance. My workbench is definitely the most important tool in my kit. Having built it myself only makes it that much more rewarding to use.

Pedro Irazoqui, Professor and Head of the Department of Electrical and Computer Engineering


Page-A-Day Calendar

David Flanigan, Program Vice Chair, Systems Engineering Johns Hopkins Engineering for Professionals

My object is the page-a-day-calendar. I ask for
these calendars every holiday from my family, usually featuring places around the world. It serves several functions: As a reminder of a location we’ve visited (or maybe should visit
in the future), as a bookmark, and as a place (on the back) for a daily to-do list or a diagram or concept that we need to discuss during a meeting. If it’s a complex situation, we may need a few of these sheets to build a story board to describe the situation.