How to Write the Caltech Supplemental Essays 2025-2026
Caltech has six required supplemental essays. Five of which are traditional prompts with no options and one unique essay prompt where you have to respond to two of four options, but it’s up to you how you divide the word count between the two options. Additionally, there is one optional essay for additional information to explain extenuating circumstances.
Because Caltech is one of the most academically rigorous schools in the country, you want to be sure that your essays capture your intellectual and creative potential. In this post, we’ll break down each prompt so that you can know what you need to do to craft responses that truly shine.
One thing to note up front: three of Caltech’s required prompts ask you to write about something to do with STEM. Given that overlap, take care that each essay shares something genuinely new about you, rather than repeating something you already say in another essay. If you’re worried about coming up with three distinct topics, remember that STEM is a broad field, with lots of nooks and crannies to explore. And, we’re here to guide you in just the right direction!
Caltech Supplemental Essay Prompts
Prompt 1: Because of the rigorous courses in the core curriculum, Caltech students don’t declare a major until the end of their first year. However, some students arrive knowing which academic fields and areas already most excite them, or which novel fields and areas they most want to explore.
If you had to choose an area of interest or two today, what would you choose? (There are dropdown menus from which you can choose up to two areas of interest.)
Why did you choose your proposed area of interest? If you selected ‘other’, what topics are you interested in pursuing? (200 words)
Prompt 2: 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. (50-150 words)
Prompt 3: Tell us how you initially found your interest and passion for science or any STEM topic and how you have pursued or developed this interest or passion. (100-200 words)
Prompt 4: Tell us about a STEM-related experience from the last few years and share how and why it inspired your curiosity. (100-200 words)
Prompt 5: The creativity, inventiveness, and innovation of Caltech’s students, faculty, and researchers have won Nobel Prizes and put rovers on Mars. But Techers also imagine smaller-scale innovations every day, from new ways to design solar cells to how to 3D-print dorm decor to experimenting in the kitchen. How have you been a creator, inventor, or innovator in your own life? (200-250 words)
Prompt 6: You have 250 words total to answer two of the four questions below.
It’s up to you how you use your 250 words, whether that means you use exactly 125 words for each answer or you tell us about a niche interest in 30 words so you can spend 200 telling us about a core piece of your identity.
There is no ‘right’ way to choose which question to answer. If you’re all STEMmed out, feel free to tell us about a creative hobby. Or if you just can’t get enough math, tell us about a concept you can barely wrap your head around.
Just remember the Caltech Honor Code and stick to 250 words total.
Option A: Hobby: What is an interest or hobby you do for fun, and why does it bring you joy?
Option B: Teach: If you could teach a class on any topic or concept, what would it be and why?
Option C: Identity: What is a core piece of your identity or being that shapes how you view and/or interact with the world?
Option D: Concept: What is a concept that blew your mind or baffled you when you first encountered it?
Prompt 7 (optional): Have you had any extenuating circumstances (such as limited course selection, inconsistent grades, or disruptions), that have affected your coursework, but that are not described elsewhere in your application? If so, tell us about them here. (150 words)
Prompt 1
Because of the rigorous courses in the core curriculum, Caltech students don’t declare a major until the end of their first year. However, some students arrive knowing which academic fields and areas already most excite them, or which novel fields and areas they most want to explore.
If you had to choose an area of interest or two today, what would you choose? (There are dropdown menus from which you can choose up to two areas of interest.)
Why did you choose your proposed area of interest? If you selected ‘other’, what topics are you interested in pursuing? (200 words)
After you select your area(s) of interest, you are asked to provide the reasoning behind your choice(s). This is a fairly standard “Why This Major?” prompt. This straightforward prompt is intended to give the admissions committee a sense of what interests you, why it interests you, and why/how you plan on pursuing this interest in college and beyond.
Before we continue, we have to address the elephant in the room—what if you’re undecided?
The bad news is that you’re required to pick at least one area of interest on your application. The good news is that you aren’t contractually bound to the area you choose! In fact, “Every first-year student at Caltech takes the same classes during their first two terms; you won’t even declare your major until the end of your first year.”
Don’t worry if you haven’t figured out exactly what you want to do in college—many students haven’t! Look through the list of areas of interest and pick one that’s closely related to a hobby or pastime of yours so you’ll have something to write about.
If you do have an area of interest or desired major in mind, great! Pick that one for your essay.
Now that you’ve picked a subject, you may find it helpful to ponder the following questions before you begin crafting your response:
1) What are your sincere reasons for wanting to major in your chosen field?
Ideally, you will have picked a field in which you have a deep interest—one that you can talk about at length. You should have meaningful reasons for wanting to pursue your chosen field. If your primary motivation involves money, status, or pressure from your parents, you’re already off to a bad start. An essay that seems disingenuous or too self-serving will detract immensely from your application as a whole, so be sure to choose substantial reasons.
2) What are some specific examples of things you enjoy about this field of study?
When answering this question, aim to be as specific as you can. Anyone can write about liking “information and data sciences” or “biology,” so think of more narrow subtopics like “principal component analysis to reduce dataset dimensionality” or “identifying mitotic mutations in fruit flies.” If you’ve picked a topic you’re already passionate about and familiar with, talking about something specific you enjoy about it shouldn’t be too daunting.
3) How does this major serve your life and/or career goals?
You might not have the most detailed plan for your career and adult life, and that’s totally fine! However, it would be helpful if you had some idea of what you want to do in the future. Think of industries you would be able to work in with a degree in your chosen field. What is your dream job? How can this major contribute to your attainment of that job and success in the field?
4) What’s your favorite experience with this subject in school? What are the best parts of your experience with it outside the classroom?
5) Is there any recurring emotion or state of mind that you experience when exploring this field of study? What do you find appealing about that emotion or state of mind?
You can use your answers to questions 4 and 5 to recall some relevant anecdotes that may contribute to your response.
Once you’ve figured out the answers to the five aforementioned questions, you can begin planning a structure for your response. You may find it helpful to break your essay into two principal parts:
- The experiences that fostered and increased your interest in this field (as well as your emotional and personal connection to your chosen major)
- What you hope to do in the future, both at Caltech and in your career
Now, you should do some research on Caltech’s website to find some unique aspects of your chosen major that you can write about. Check out Caltech’s list of majors, as it has links that will lead you to each major’s respective webpage. Also consult their lists of faculty members and research facilities to see what work Caltech is doing in your area of interest.
For example, consider a hypothetical student who wants to pursue bioengineering with a particular interest in stem cell research. She might begin with an anecdote about how her father was a participant in a clinical trial for stem cell therapy after his spinal cord treatment. Perhaps seeing the potential of stem cell treatment opened up a new world for her, which fostered a deeper interest in biology and bioengineering than she had ever had before.
She might write about her high school experiences with biology classes, her intensive preparation for the AP Biology exam, and the bioengineering publications she now likes to read in her free time. She can then transition into a discussion of what kind of research she would like to be a part of at Caltech. A faculty member she can talk about specifically is Professor Magdalena Zernicka-Goetz, whose lab used stem cells last year to create model mouse embryos “that have beating hearts, as well as the foundations for a brain and all of the other organs in the mouse body.”
No matter how unique, weird, or quirky you think your interests are, there will probably be a major or research group at Caltech that can cultivate them. Don’t be afraid to show how unique you are as an individual—that’s the point of supplemental essays!
Prompt 2
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. (50-150 words)
As Caltech is a STEM-focused institution, it is unsurprising admissions officers want to know all about your scientific or mathematical passions. While the first prompt is focused on your intended major, here, you get the chance to talk about whatever you want in this realm. If there’s something you love learning about, but might not have had the chance to pursue in a formal context, this prompt is a great place to talk about it!
Of course, you’ll want to make sure that what you choose will help you stand out from the rest of the crowd of applicants, so let’s talk about some ways to make your essay unique.
- Do you have a STEM-related passion that is unusual or unique? Perhaps the passion itself is very specific, or you are approaching a common topic in a different way than others.
- Have you had any personal experiences that have led you to a passion you wouldn’t otherwise have? Do aspects of your personality or life inform a passion of yours in a way that’s particular to you as an individual?
- How has your interest in a topic evolved over time? Has a run-of-the-mill interest developed into a passion? Has your interest shaped your life or academic journey in a remarkable way?
- Have you engaged with your passion in an exceptional way? Beyond googling, taking classes, or reading books, have you sought out experiences, pursued knowledge, or done some kind of work to spend more time with this topic?
Hopefully, at least one of these questions will help you think of a passion to write about. After that, it’s all about how you frame your story.
While your first instinct might be to describe your passion in a factual, straightforward way, remember that with any college essay, your goal is to teach admissions officers about who you are, not the topic itself. So, a more effective approach would be to explain how you developed your passion, how it influences your perspective on the world, and how it fits into your broader life and personality.
Let’s look at an example that illustrates how this strategy might look in action.
“‘Spooky action at a distance’ – how those words send a thrill up my spine! When I first stumbled upon the concept of quantum entanglement while reading an article about quantum computing, I immediately fell into a rabbit hole. Fascinated, I devoured everything I could find on the topic—from Richard Feynman’s lectures to obscure online forums.
The idea that two particles can remain connected across vast distances, influencing each other instantaneously, blows my mind. I’ve even started experimenting with quantum simulations on my computer, hoping to someday contribute to advancements in quantum cryptography.”
The first strength of this response is that the student has gone beyond the general topic of “quantum physics,” which lots of Caltech applicants will likely be interested in, and focused in on quantum entanglement in particular. This specificity helps demonstrate what interests and perspectives they have that other students might not.
Even better, we learn that they read up on the subject in their free time, which shows that they are a self-motivated learner who pursues knowledge everywhere they can find it—just the kind of student who’s ready to take advantage of all Caltech has to offer.
Finally, the cherry on top is that they’re already imagining potential future uses of quantum entanglement, which gives Caltech admissions officers confidence that this student will utilize their school’s resources to make a genuine difference in the world.
Prompt 3
Tell us how you initially found your interest and passion for science or any STEM topic and how you have pursued or developed this interest or passion. (100-200 words)
Though this isn’t exactly either archetype, looking at our breakdown of the common “Why this Major” essay, or of the extracurricular activity archetype, might be helpful. Like the “Why this Major” essay, this prompt asks you to consider where your STEM interests came from, and like the extracurricular activity essay, it wants you to reflect on something to which you’ve dedicated significant time and attention.
You have only 200 words to explain both where your passion began and what you’ve done to pursue it since, so you’ll want to choose your topic, and your words, carefully. Consider the following examples of students who sparked their STEM passion in a unique way.
- A student interested in microbiology might write about how their frequent childhood illnesses led to a fascination with germs and all things microscopic.
- A digital artist could talk about how their desire to animate their creations led to an appreciation of the artistry behind video games.
- A student whose interest in chemistry began in the kitchen, where they wanted to understand how temperature and ingredients came together to make a dessert come together or fall apart.
After selecting your topic, you’ll want to think about how to tell a captivating, unique story that shows how your passion has shaped your growth and development. Though this is a STEM prompt, you don’t want to be too technical or information-heavy; at the end of the day, this essay is about you. Your personal connection to, and genuine interest in, the topic are more important than cramming in every single nitty gritty detail.
Let’s look at two examples of the same essay topic – one that is executed well, and the other, less so.
“When my little brother was fitted with his first prosthetic arm, I was seven and couldn’t stop staring. The way it moved – stiff, mechanical – seemed worlds apart from the ease of a natural arm. I wondered if he could use it to climb to the top of our bunkbeds – but he discarded it a week later, finding it less useful than the stump it was meant to cover.
As the years passed, the memory nagged at me. Determined to make a difference, I began sketching ideas for a more flexible prosthetic, blending art with engineering. I borrowed books on biomechanics and spent evenings tinkering with 3D-printed models in our garage.
In the past four years, my designs have become so much more sophisticated through consultation with a local rehabilitation center, listening to the stories of amputees and understanding their needs. Each interaction deepens my resolve to create a prosthetic that feels like an extension of the body, not a foreign object. As I learn to code and operate 3D printers, my vision has evolved from sketches to functional prototypes. My brother’s smile when he tries on a new, comfortable limb confirms it every time—I’m on the right path.”
Now consider this example:
“My interest in biomechanical engineering began when I observed the limitations of current prosthetic limbs. The rigid, hinge-based designs often fail to replicate the fluidity of human movement due to insufficient consideration of biomechanical principles. To address this shortcoming, I researched the mechanical properties of various materials and their applications in prosthetics. Using CAD software, I designed 3D models of flexible joints that mimic the natural motion of human limbs.
My focus then shifted to material science, where I explored the use of thermoplastic elastomers for creating more adaptive prosthetics. I conducted tensile strength tests on these materials and analyzed their performance under various stress conditions. Through work with users, I gained insights into consumer feedback, which informed further iterations of my designs. The end goal is to develop prosthetics that not only restore basic function but also enhance the quality of life for users through superior engineering.”
The second essay may be more informative about actual methods, but the first is more memorable, because it tells you more about the actual student.
It does this by starting with a vivid memory, which shows the student’s personal motivation for becoming passionate about prosthetics, and goes on to describe how they became more committed to helping amputees through work at a rehab center. The latter essay demonstrates specific scientific knowledge, but we don’t get to learn much about the student themself, and what they might bring to campus.
Caltech admissions officers are reading these essays to learn information that they can’t get from your transcript or test scores – what kind of roommate you’ll be, for example, or how you’ll navigate the jungle that is a college dining hall. They already know you’re intelligent, so show them what else you have to offer.
Prompt 4
Tell us about a STEM-related experience from the last few years and share how and why it inspired your curiosity. (100-200 words)
This prompt is supposed to gauge your interest in and experiences with STEM, both in school and in your personal life. Writing a successful essay will ideally show the admissions committee a few things:
- You are serious about pursuing STEM in college and beyond.
- You have hands-on experience in STEM.
- You have at least some idea of what to expect from a STEM-based education at Caltech.
First, even though the prompt specifies that you can write about experiences both within and outside the classroom, you might find the tips in our guide to the extracurricular activities essay helpful.
To pick a topic, think about the experiences you’ve had with science fairs, robotics clubs, biology or chemistry classes, etc. Narrow down your experiences to the ones that had the most significant impact on your interest in STEM. If you write about an experience that you didn’t have too much emotional investment in, you might inadvertently express a tepid interest in STEM as a whole.
For example, perhaps you worked alongside a pharmacist during high school. Some people consider pharmacy to be more medical and less STEM-related, but the field of pharmacology is indisputably a branch of biology and chemistry.
Don’t be afraid to bend some definitions when identifying meaningful STEM experiences you’ve had. Caltech is asking you to write a lot of essays about your interest in STEM, and you don’t want to repeat yourself, so getting creative with how you interpret “STEM-related” could serve you well.
You could even get more creative than the pharmacist example above. For example, maybe in addition to loving math, you’re an avid Seattle Seahawks fan, and you once did a project breaking down game film to determine which play calls optimized a receiver’s separation from their defender.
This kind of out-of-the-box approach can be extremely effective for setting you apart from all the other talented Caltech applicants out there, but it’s also harder to execute well. If you’re feeling iffy, stick to something more conventional—a straightforward essay that teaches admissions officers something about you will help your odds of admission much more than a creative one that doesn’t land.
If you’re having a hard time brainstorming, mull over a few questions:
1) What is your favorite STEM-related activity? If you don’t have a good STEM activity, which of your non-STEM activities can be linked to STEM logically?
2) What about this activity generated your interest in STEM? Why did it make you curious and how did your participation in it increase your interest?
3) What went through your mind as you participated in this activity? Do you use any skills that are connected to STEM work, like computation or analysis?
4) Have you developed or strengthened any specific interests because of this activity? If so, what are they and how have they changed over time? For example, you might have been interested in chemistry in general, but this particular activity focused your attention on metal alloys.
5) Are there any specific STEM-related skills that you have developed as a result of participating in this activity? Think about hard skills like chemical titration, building robots, testing the pH of substances, etc.
Once you’ve decided on your activity, you can begin writing your response. Remember to address each point of the prompt:
- How did the activity activate your curiosity?
- Why did the activity activate your curiosity?
- What about the activity made you want to learn more and explore further?
For example, consider the following response by a hypothetical student:
“During my junior year, I joined the Robotics Club with no prior experience, other than having taken AP CompSci. Our team’s first project involved building and coding a robot that could get to distant water sources, collect water, and purify and store it. We spent several weekends and late nights programming the bot and troubleshooting it.
It had trouble navigating at first, then it failed to recognize the water sources. Finally, we completed the build in a few months, and though it was far from perfect, it did the job. That first drink of purified water from the bot was beyond refreshing.
That project was the one that truly showed me how useful robotics could be to humanity. I imagined building hundreds of robots like the original and sending them to developing countries to increase their access to clean drinking water. I am now drawn to mechanical engineering because it offers limitless opportunities to create devices that can be used to improve the world and people’s quality of life.”
This example is effective because it incorporates an engaging anecdote, addresses each point of the prompt, and offers a plan for the student’s college career and future professional life. After reading this essay, Caltech admissions officers will undoubtedly feel more confident about their fit with this STEM-focused institution.
Prompt 5
The creativity, inventiveness, and innovation of Caltech’s students, faculty, and researchers have won Nobel Prizes and put rovers on Mars. But Techers also imagine smaller-scale innovations every day, from new ways to design solar cells to how to 3D-print dorm decor to experimenting in the kitchen. How have you been a creator, inventor, or innovator in your own life? (200-250 words)
This prompt is trying to determine how you think as a problem solver. The admissions committee wants to know the ways in which you have been innovative or have approached problems creatively.
Don’t feel like you have to have developed some revolutionary solution to a global problem. No one is expecting you to have engineered some brilliant scientific apparatus—you haven’t even graduated high school yet! Just like the prompt’s examples illustrate, you can think on as big or as small a scale as you’d like.
When trying to choose an example of innovation in your own life, it might be useful to think about abstract qualities then work your way to concrete events. Are you ambitious, adaptable, creative, resourceful, open-minded? What are some positive qualities of yours? Once you’ve decided on some attributes, you should be able to relate them to some anecdotes.
Let’s say you’re creative and resourceful. Think of a time when those traits generated something innovative or novel in your life. Maybe you were locked out of your apartment and used a credit card to open the latch. Perhaps this experience inspired you to 3D print a plastic card to use specifically for problems like that.
Your story of innovation can involve anything really, as long as you came up with a creative solution to a problem you were confronted with. Maybe the arm of your glasses broke in the middle of class, so you attached a pen cap to it so the glasses could still be used until you had time to replace them.
You have 250 words, so you may want to think of 2-3 anecdotes to discuss. It might even be helpful to write about something you want to improve but haven’t yet. You can talk about a persistent problem you’ve seen and propose a creative potential solution.
Here’s an example of an anecdote a student might describe:
“I worked at a hardware store during high school to help my parents pay some bills. The store was far from my home, and often took about an hour to get to by public transportation. I’ve always been interested in tinkering with mechanical devices, so I decided to make the most of my job.
I bought parts from the store with portions of my paycheck every couple of weeks, and over the course of several months I built myself a bicycle from scratch. Of course, it wasn’t the most visually appealing or comfortable bike, but it did the job and it did it well. I don’t use it much anymore, but I still own it and feel great pride every time I pass it on my way out the door.”
This is a good anecdote because it presents an issue, describes something about the student’s creative and inquisitive nature, and showcases the innovative solution that the student devised.
You may want to approach this prompt in a similar way. Outline a problem you had to deal with, describe some relevant positive attributes about yourself, then explain how these attributes helped you find an innovative solution to the problem.
Prompt 6
You have 250 words total to answer two of the four questions below.
It’s up to you how you use your 250 words, whether that means you use exactly 125 words for each answer or you tell us about a niche interest in 30 words so you can spend 200 telling us about a core piece of your identity.
There is no ‘right’ way to choose which question to answer. If you’re all STEMmed out, feel free to tell us about a creative hobby. Or if you just can’t get enough math, tell us about a concept you can barely wrap your head around.
Just remember the Caltech Honor Code and stick to 250 words total.
For this next set of prompts, Caltech has created a pretty unique option. Four prompts, two of which you respond to, and while the responses have to be less than 250 words altogether, it’s up to you how to spend those words.
Reading through these prompts, you may have an immediate idea of which ones you want to respond to. Spend some time considering each, and prioritize the ones that allow you to expand on something that’s been missing so far from your application. Maybe you can bring up something you haven’t had the chance to discuss, or dive in depth into something that’s only been mentioned in passing. Try not to use these prompts to expand on something addressed in your Common App essay or earlier supplements.
Prompt 6, Option A
Hobby: What is an interest or hobby you do for fun, and why does it bring you joy?
Given the length of these prompts, they’re more like short response questions than full supplemental essays. Still, this fits into the Extracurricular essay archetype, which asks you to reflect on something you’ve spent particular time on, why that hobby matters to you, and what it might say about your character, values, or future goals.
You already have a list of extracurriculars as part of your Common App and may even have more hobbies that you didn’t have the space to include. It can be hard to decide which to write about, so consider these questions to help you choose what to focus on.
- What’s something you do purely because you love it, not because it looks good on a résumé?
- What’s your “flow state” activity — the thing that makes you lose track of time?
- How did you discover your hobbies? Any funny, unexpected, or memorable origin story?
- Do you participate in an activity that challenges you or makes you think differently? Have any of your hobbies truly changed you or your life?
- Do you have a hobby that connects to any broader themes in your life — curiosity, persistence, creativity, community?
A good choice for this response is an activity or extracurricular that is unique, meaningful, and specific. You also want to focus on you, so your reader comes away knowing more about your connection to your hobby than about the hobby itself. In a supplement this short, it’s hard to lean into sensory detail, but try to anchor things with a few clear descriptions or an anecdote that brings your interest to life.
Let’s look at a good example that incorporates these elements for a memorable response. This one is 150 words, but remember, depending on how you allocate your words, yours could be longer or shorter.
“Every Friday night, my kitchen turns into a makeshift pizzeria. I dust the counter with flour, stretch dough until it’s paper-thin, and listen for the tiny hiss when it hits the hot stone. My friends hover nearby, arguing over toppings—pineapple is a nonnegotiable in my house. When toppings are decided, they dive into the artistry of the night, one singing improvised “pizza opera” while another arranges pepperoni in Fibonacci spirals. Me, I love the science of baking —perfecting hydration ratios, sensing when the crust is just shy of blistering—but I also see the theater: the hiss of dough on the stone, the basil perfume rising with the steam, the collective cheer when we slice the first pie. Pizza night began as a quarantine survival tactic; now it’s my laboratory, my stage, and my favorite reminder that joy thrives in the messy, delicious intersection of creativity, precision, and shared laughter.”
This response features a strong hook, vivid language, and lots of personality—not a lot of people are putting Fibonacci spirals on their pizzas! It demonstrates this applicant’s commitment to both creativity and community, while also showing that they have a serious commitment to this hobby through the discussion of hydration ratios and basil perfume. We learn a lot about the author through their Friday night ritual. Aim to pack that kind of depth into your response, whether your hobby is pizza making or political organizing.
Prompt 6, Option B
Teach: If you could teach a class on any topic or concept, what would it be and why?
In this short response question, Caltech wants to know what fascinates you so much that you would, and perhaps could, teach it. It’s another way of getting at your passions, which reveals both what you care about and the way that you think about it. You can demonstrate not just what you spend your free time thinking about it, but how you frame and approach problems.
The best responses will, of course, be unique; you want to stand out to an admissions officer reading hundreds of these essays. A personal connection tends to help accomplish this, as well as letting this question reveal more about you and your personality. Contagious enthusiasm, excitement, and a balance of rigor and playfulness are all crucial qualities you can demonstrate here.
Let’s look at some hypothetical student examples that show promise for this topic.
- Diego – “The Physics of Parkour”: A lifelong parkour enthusiast who breaks down momentum, center of mass, and force distribution during vaults and wall runs. He loves showing how equations apply mid-leap.
- Maya – “Cooking with Chemistry: The Science of Ice Cream”: Started making small-batch ice cream with liquid nitrogen in high school. Her class would teach thermodynamics, crystallization, and flavor innovation.
- Noah – “The History and Math of Cryptography”: Got hooked after solving ciphers in puzzle hunts. His course blends number theory with stories of wartime codebreakers.
While not required, each of these applicants has demonstrated an interdisciplinary approach, showcasing an appreciation for the depth that can be added by viewing something from multiple angles. They have catchy but informative titles for their courses, and demonstrate how this course would be personally fulfilling and engaging for them, not just a dry intellectual exercise.
As you choose your own topic, avoid selecting something just because it sounds impressive or because it ties into career goals. All of these supplements are more about passion and personality than they are about showing off or future planning. To that end, don’t be afraid to lean into the class format and demonstrate depth of knowledge by citing potential textbooks or guest speakers. Make it clear that this is something you care about and can communicate to others, and the Caltech admissions team is sure to appreciate it.
Prompt 6, Option C
Identity: What is a core piece of your identity or being that shapes how you view and/or interact with the world?
Though this is a short response question, it does fall under the Diversity archetype by asking about identity. Don’t let that scare you away from answering this one—diversity and identity are broad terms, which can encompass everything from racial or ethnic diversity to spiritual identity, regional identity, or a deeply felt connection with a value, hobby, or interest.
Since this is one of the more broad prompts, it’s especially important to avoid cliche topics that many other students might be writing about. Common topics include moving from one country to another, being a first generation American, overcoming a personal loss, persevering or being a leader in a sport or extracurricular, or focusing on a future profession as an identity marker. None of these are inherently bad topics, but hundreds of thousands of other applicants likely share these stories.
So, how do you make your essay stand out? First, if you have an identity that truly is unique, now is the time to write about it! Maybe you’re a quadruplet, a polyglot, or you’ve been DMing roleplaying games since you were twelve. What makes a particular identity truly unique is usually rarity. That can mean that you’re one of a select few, but it can also mean that your commitment is unusually strong or unusually long.
If you don’t have an identity that’s one-of-a-kind, that’s okay! Most of us don’t. This is where bringing in personal details, showing both the origin and evolution of your identity, and letting your interaction with the world shine can really help. It also doesn’t hurt to lean into traits prized by Caltech, like analytical thinking, collaboration, love of learning, or joy in problem-solving.
Let’s look at a few examples of what an effective identity essay might look like.
- Lena’s childhood foraging for mushrooms has evolved into an identity as the “fungi girl” who knows the name of all the local flora. Her appreciation for mycorrhizal networks has informed her view of the world as an interconnected web where unseen relationships quietly sustain life. That belief shapes how she collaborates in group projects and seeks interdisciplinary links in science.
- Ravi’s grandparents ran a bicycle repair shop in Mumbai. He grew up with grease-stained fingers, seeing trial-and-error as a way of life. This identity as a “fixer” now shapes how he approaches coding bugs, engineering challenges, and even gaps in understanding between people.
- Marina grew up in a fishing town, and saw firsthand the fragility of marine ecosystems. Her environmental consciousness drives both her scientific research and her daily choices, from advocacy projects to reducing waste.
Each of these examples shows not just what the student’s identity is, but how that identity has shaped their personality, interests, and worldview. One is formed around an interest, one around a hobby, and one around a strong connection to the writer’s hometown.
Now, choosing a good topic is only part of the process. Let’s dive deeper into Ravi’s essay, comparing and contrasting a bad example of a full-length response with a more effective one.
Bad example:
“My Indian heritage is a crucial part of the person I am today. Growing up helping out in my grandparents’ bicycle shop in Mumbai taught me my culture’s value for hard work and family. I learned to appreciate the bright colors and draping fabrics of customers’ saris and was fascinated by the dozens of regional dialects our customers brought into the shop. There were days I would rather have run around with my friends than greased bike chains, but looking back, I’m glad I spent time at my grandfather’s side, helping him run the business that sustained my family.”
While this essay contains vivid detail and a discussion of the author’s values, it’s also superficial and skips around a bit without diving deeply into any particular subject. The author mostly sticks to telling us about what he experienced rather than showing it, and doesn’t connect his childhood experience to himself or his personality today.
Good example:
“My identity is built on the smell of machine oil from my grandparents’ bicycle shop in Mumbai, where I learned that fixing things means listening first — to creaks, wobbles, and people. Customers came with problems we’d never seen, or speaking a language even my polyglot grandfather didn’t know, and every time, care, attention, and perseverance won the day. That workshop spirit followed me to my garage in California, where I tinker with drones and help neighbors repair lawnmowers. My Indian heritage isn’t just tradition; it’s a blueprint for resourcefulness, collaboration, and finding joy in solving problems, no matter the scale.”
This is a whole different response—it’s immediate, vivid, and clearly relevant to the author’s day to day. The values of hard work and family are still there, but they can go unspoken, allowing the author to delve into deeper values his culture prizes, like resourcefulness and collaboration.
Prompt 6, Option D
Concept: What is a concept that blew your mind or baffled you when you first encountered it?
The name of the game here is intellectual curiosity, capacity for wonder, and perhaps most importantly, some humility. Here, Caltech isn’t just asking about what you’re curious about and how you’ve engaged with it, but also your own readiness to admit that you don’t always have the answers, that you might have to be comfortable with not knowing. What do you do when something unexpected challenges you? If you have an answer ready, this could be the prompt for you.
You might not have an answer ready, and that doesn’t mean you should skip this prompt. Consider some of these questions to get those gears turning.
- What’s the first moment you can remember when a concept made you stop and say, “Wait, what?”
- Have you ever taken a class, read a book, watched a documentary, or otherwise encountered something that totally changed how you viewed a topic?
- Has your understanding of an idea ever been seriously challenged? Have you ever had to go back and revise something you thought you knew?
- How have you reacted to your knowledge being challenged? Have you ever gone above and beyond to increase your understanding?
- Has your understanding of a concept evolved significantly over time?
- Are there any ideas you’ve gotten lost in that connect to how you think about the world now or what you want to study?
Any or all of these questions can provide a good jumping off point for a response about something that boggles your mind. A good response will feature that emotional reaction for immediacy and authenticity, emphasize persistence and curiosity through continued engagement with this idea, and show the “before and after,” which demonstrates your capacity for insight and your ability to evolve and change.
This might sound like a lot to keep track of, but most of these things will come pretty readily in a story about a time that learning expanded your mind. Be sure to avoid common pitfalls like picking a topic that’s trendy rather than interesting to you, writing a technical summary that doesn’t include your human process of understanding, and choosing something that you don’t deeply understand, forcing you to remain vague. Let’s look at two hypothetical student examples and compare which is stronger.
- Kian: As a math club captain, Kian thought math was about finding definite answers. Discovering Gödel’s Incompleteness Theorems shattered that assumption and led him to see mathematics as a creative, self-reflective human endeavor.
- Ayesha: Ayesha writes about how she’s fascinated by the idea of creating bacteria that produce insulin. Learning about CRISPR and bioengineering has totally shifted her idea of how science can revolutionize medicine.
In the first example, Kian demonstrates a long-term connection to math, a deep engagement with complex topics, and a mature evolution in how he sees mathematics as a field. Ayesha, though she is reflecting on an interesting and worthwhile topic, doesn’t show us why it matters to her, what her ideas around science and medicine might have been before, and why this realization was significant to her. The result is that we know a lot more about Kian than about Ayesha.
Luckily for this hypothetical student, her essay is totally fixable. Anchoring to a personal moment or setting would provide the necessary background, and it doesn’t need to be a deeply personal connection to diabetes or healthcare. Just citing how she arrived at this interest would make the story more specific. Ayesha should also show the emotional impact of her learning journey, and highlight her active engagement by talking about what she did to learn about CRISPR and bioengineering.
Prompt 7 (optional)
Have you had any extenuating circumstances (such as limited course selection, inconsistent grades, or disruptions), that have affected your coursework, but that are not described elsewhere in your application? If so, tell us about them here. (150 words)
This essay is a little different from the other optional supplements— it’s what we call an Exceptional Personal Circumstances essay. Though we usually recommend that you respond to every prompt you possibly can, this supplement is the exception. Only respond to this prompt if you have truly experienced something that significantly disrupted your high school experience. Writing an extraneous response here will not be viewed positively by the admissions committee.
On the flip side, if something has impacted your academics, and Caltech is specifically asking about your academics here, it’s absolutely worth taking the time to explain that to the admissions committee. This prompt is even a little more flexible than many others like it, asking about factors like limited course selection. So, let’s talk about how to determine if you should respond to this prompt.
Here are some questions that may help you decide.
- Did the event or events in question impact your ability to attend school?
- If you were physically present, did anything impact your ability to fully engage with your coursework? Maybe you were adjusting to a chronic illness, distracted by grief over a loss, or had to split focus between homework and a part-time job.
- Have you ever been unable to access resources that were necessary to succeed in school? Not having consistent wifi or money to buy books could certainly have impacted your academic performance.
- Did anything prevent you from reaching your full academic potential? Maybe there were no seats left in an honors class, or a course previously offered was not taught the year you wanted to take it.
Keep in mind that while Caltech offers broad guidelines about academic interruptions, this prompt does not extend to circumstances that may have impacted extracurricular involvement or disciplinary or legal action, the way other exceptional personal circumstances prompts do. It’s also important to note that this prompt is primarily looking for circumstances beyond your control, so not being able to buy the best calculus textbook on the market, or freely choosing to do a part-time job that then affected your grades, are not good reasons to respond to this prompt.
If you’ve gotten this far and determined that you should be responding to this prompt, write your response while keeping in mind that this question is purely informational. Now is not the time to demonstrate your storytelling skills or verbal artistry; keep things clear, direct, and as detailed as is necessary without wasting time.
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