Caltech Supplemental Essays 2025-2026: Requirements, Prompts and Winning Examples

Caltech utilizes the Common Application or QuestBridge Application. You will complete several writing supplements.

1. STEM Academic Interest Question (100–200 words)

"If you had to choose an area of interest or two today, what would you choose? … Why did you choose your proposed area of interest? If you selected ‘other’, what topics are you interested in pursuing?"

I would choose to study Mechanical Engineering and Computer Science. My interest sparked when I tried to build a small, autonomous drone for a science fair project. I quickly realized designing the physical frame was only half the battle. The real challenge was in the code, specifically writing a flight stabilization algorithm that could react to unpredictable wind. That single problem showed me a fascinating intersection where the physical world of forces and materials meets the logical world of software.

I pursued this interest by teaching myself Python to model the physics of simple machines before applying similar principles to flight dynamics. At Caltech, I want to keep exploring this connection. I am drawn to the university’s focus on fundamental research and its interdisciplinary culture, and I hope to contribute to projects at the Center for Autonomous Systems and Technologies (CAST).

2. STEM Curiosity Essay (50–150 words)

"Regardless of your STEM interest listed above, take this opportunity to nerd out and talk to us about whatever STEM rabbit hole you have found yourself falling into. Be as specific or broad as you would like."

My most recent rabbit hole has been knot theory. It started with a simple question: how can you mathematically prove that a knot is truly a knot? This led me to topology and concepts like Reidemeister moves and knot invariants. I spent weeks learning about different polynomial invariants, like the Jones polynomial, which can distinguish between types of knots. What truly surprised me was learning about its application in biology. DNA strands can become knotted during replication, and the enzymes that unknot them, topoisomerases, are basically nature’s topologists. Realizing that this abstract math has a direct and critical application in life's fundamental processes is what makes science so compelling to me.

STEM Experience Essay (Choose 1 of 2 options, 100–200 words)

Option 2:"Tell us about a meaningful STEM-related experience from the last few years and share how and why it inspired your curiosity."

My most meaningful STEM experience was a failure. At last year’s regional robotics competition, our robot was designed to navigate an obstacle course autonomously. It performed flawlessly in our workshop, but under the bright lights of the competition arena, its optical sensors failed. Our robot, blind and confused, crashed into the first wall. We were eliminated in the first round.

That failure was frustrating, but it sparked my curiosity. The problem wasn’t our mechanics or our code, but our robot’s inability to adapt to a new environment. Why was it so easily fooled by a change in lighting? This question inspired me to dive into computer vision and sensor fusion. I spent the next few months learning how neural networks can be trained to recognize objects under various conditions. That single failure taught me more than any success. It shifted my focus from just building robots to the harder problem of how they see the world.

Creativity in Action Essay (50–150 words)

"How have you been a creator, inventor, or innovator in your own life?"

My family's digital photos were a mess, scattered across a dozen different folders. To solve this, I created a Python script that organizes them automatically. File names were inconsistent, so my solution was to use each photo’s EXIF metadata. The script reads the date and time a photo was taken and sorts over 10,000 images into a nested folder structure by year, month, and day. It also uses basic image recognition to group photos taken in quick succession into event-based subfolders. What was once a digital junk drawer is now a browsable family history.

Short-Answer Questions (Choose 2 of 4 / 250 words total)

You will select two from the following four prompts:

"What is an interest or hobby you do for fun, and why does it bring you joy?"

"If you could teach a class on any topic or concept, what would it be and why?"

"What is a core piece of your identity or being that shapes how you view and/or interact with the world?"

"What is a concept that blew your mind or baffled you when you first encountered it?"

If you could teach a class on any topic or concept, what would it be and why?

I would teach a class called "The Physics of Flavor." We would explore the science behind why we love food, from the Maillard reaction that gives a steak its crust to the thermodynamics of slow-cooking. The class would be part chemistry, part physics, and part hands-on kitchen lab. I would teach it because it shows that complex science isn't just for laboratories; it's happening in our kitchens every day. It would be a delicious way to make science accessible and prove that understanding the world can be fun.

What is a concept that blew your mind or baffled you when you first encountered it?

The concept of emergence baffled me when I first heard of it. The idea that complex systems, like an ant colony, can arise from simple agents following basic rules without a central leader seemed impossible. It challenged my top-down view of how order is created. It blew my mind by providing a new framework for understanding everything from galaxies to our own brains. It showed me that the most complex structures aren't always designed; they can emerge from simple interactions.

All the best!