How to Write the Caltech Supplemental Essays 2022-2023

The California Institute of Technology (Caltech) is one of the nation’s most renowned STEM schools. When applying to Caltech, in addition to the personal statement on the Common App, Coalition Application, or QuestBridge Application, students are required to respond to four supplemental college-specific prompts. Caltech offers three optional prompts as well.

Caltech admissions are extremely competitive, so you should treat the supplemental essays as your opportunity to stand out—they’re the part of the application where you can show that you are more than just grades, test scores, and a list of activities!

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Caltech Supplemental Essay Prompts

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?” essay. 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 major 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. 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.

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 for 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 recently used stem cells 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!

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.

You’ll probably know if an experience is related to STEM at first glance. Nevertheless, before you begin writing your responses to this prompt, you should make sure you have a handle on what exactly STEM is, even if you think you understand it fully.

As a quick refresher, STEM stands for Science, Technology, Engineering, and Math. It heavily emphasizes analytical and critical thinking skills, scientific literacy, and domain-specific hard skills that are essential to many career paths.

Even though the prompt specifies that you can write about experiences both within and outside the classroom, you might find the tips in CollegeVine’s guide to the extracurricular activities essay helpful.

If you have any obvious STEM experience, picking some events should be fairly straightforward. 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.

If you only took one science class in high school and didn’t participate in any STEM-related extracurriculars, don’t fret! Feel free to write about two experiences from the same class. You might even be able to relate some work experience to STEM. 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.

To help you identify your two experiences, 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 galvanized 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?

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 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 two activities, you can begin writing your responses. For each activity, you should 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?

After addressing each point, if you still have room within your 200 words per activity, you can explain some things further. Perhaps you want to discuss something specific that you learned or exactly what your role was in the activity.

For example, consider the following response by a hypothetical student:

During my junior year of high school, 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 tells an engaging anecdote, addresses each point of the prompt, and offers a plan for the student’s college career and future professional life.

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 begun college yet! Just like the prompt’s examples illustrate, you can think on as big or 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 decide 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 write:

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.

This prompt may look long and daunting, but it’s a relatively straightforward “Diversity” essay at its core. Caltech recognizes that everyone has a distinct background and comes from a different walk of life. The admissions committee wants to know who you are, where you come from, and what unique perspective you’re going to bring to their campus. This essay is your chance to tell them about your identity.

You only have 250 words, so you can’t tell Caltech about every part of your background. To figure out what aspect of your identity you want to write about, consider the following questions:

1) What is your background and what specific communities do you belong to? “Community” is an intentionally vague term. Your background can include many things. A community can consist traditional markers of diversity, such as ethnicity, race, gender identity, sexual orientation, country of origin, or language.

Note: Diversity comes in all shapes and sizes. Besides the more traditional examples above, your background can include your hometown, income class, illness/disability, or even interests and hobbies!

2) How has your background influenced your development as a person? Have you developed any skills or personality traits through this background? If so, how have these traits evolved over time?

3) Have any of the formative events in your life been caused by this background? What were they and how did they shape you into who you are today?

After you figure out which part of your identity you want to discuss and the answers to the above questions, you can begin crafting a narrative arc for this essay. Consider your feelings about your background and experiences as a person with your background, then try to think of important anecdotes that illustrate how this background has shaped your worldview.

When writing your response, there are some common mistakes to avoid:

• Don’t list every facet of your identity. You don’t have a lot of words to work with, so don’t waste too many on making a list. Pick one aspect of your identity and elaborate on it.

• Don’t only write about overly negative experiences. Your background may have generated some adversity during your life, but admissions committees often look for experiences with positive outcomes or lessons. Not everything has a “happy ending,” but writing an essay with a negative tone will be harder to execute well.

• Avoid cliché topics. Stories about immigration or moving across the country are valid ways to describe your background, but they’re very common and hard to write about in a unique way. If this is central to your identity, it’s fine to still write about it, but you should focus on a specific aspect of this experience rather than generally having to adapt to a new environment.

For example, consider a student who grew up in a household full of musicians. Perhaps his mother is a classically trained guitarist and his father is a jazz pianist. He might consider music to be such an important part of his identity that it defines the way in which he confronts problems.

When writing his essay, the student might begin with an anecdote about a problem he faced – being locked out of his apartment without his keys. He first confronted the problem in the way his classically trained mother would play guitar, using reliable and traditional means. He tried to pry the door open, to slip his credit card into the frame to push the latch, to pick the lock with a paperclip he had – all to no avail.

After finding no success with his first few attempts, the student switched over to thinking in a more creative, less structured way, much like how his father plays piano. He tried loosening the door’s hinges with his fingers with no success, then went out back. Finally, after using the hooked handle of his umbrella to pull the ladder down, the student got up the fire escape and into his apartment through his bedroom window.

This creative example works because it shows how the student’s diverse musical education, an integral part of his background, has had an impact on the strategies he uses to solve everyday problems.

Describe a part of your background, why it’s been important to your development as an individual, and how it has changed the way you experience or view the world. If you do all these things, you will have a successful and compelling response to this prompt.

While we typically encourage students to respond to optional prompts, there’s no need to write additional information here if you feel that your application captures your identity. 

As with the previous prompt, this is essentially a “Diversity” prompt. There are a couple of differences between this prompt and the previous one, though. Firstly, this prompt has a word limit of 150 words, so if you choose to respond to it, you’re going to have to be more succinct. 

Secondly, you will have to approach your identity from a different perspective. Discussing a very similar part of your identity will feel redundant and won’t contribute to your application in a meaningful way. For example, if you wrote about being a guitarist in the previous prompt, you should avoid writing about being a pianist here.

Remember, identity emcompasses a wealth of attributes. Your identity can include your ethnicity/race, gender identity, sexual orientation, country of origin, first language, hometown, socioeconomic class, illness/disability, interests, or hobbies.

There are two strong approaches to writing this essay.

The first approach involves doing something totally novel. You might want to pick a completely new aspect of your identity that is fully distinct from your previous one. For example, if you wrote about your gender identity already, you may choose to write about your ethnic background now. This can be a useful approach if certain parts of your identity hold a similar level of importance to you.

The second approach involves building upon your previous essay. Perhaps there is an aspect of your identity that is related to the one you just wrote about, but distinct enough to warrant a new essay. Maybe you wrote about being Hispanic in the previous essay, and now want to write about the Spanish language. The language you speak might be an integral part of your identity. It isn’t the same as your ethnic background, even if the two are closely linked, so something like that would be fair game for this prompt.

Remember to avoid listing aspects of your identity, writing too much about something negative, and discussing a topic that’s too cliché. This is another chance to showcase who you are. During the admissions process, there aren’t too many of these opportunities, so make the most of them!

This prompt is meant to gauge who you are beyond your grades and test scores. It’s an optional prompt, but we strongly recommend writing a response to it, as this gives the admissions committee more knowledge about you. 

Caltech wants to know what interests you outside of school, and what hobbies you might bring to their campus. Your hobbies don’t necessarily have to be the traditional extracurricular activities, but you might still want to look at our guide to writing the extracurricular activities essay for some tips!

Before you begin writing, it’s important that you select a strong topic. Of course, you need to be sincere. Don’t write about a topic you don’t consider a hobby just because you think the admissions committee wants to read about it. An authentic topic will always make for a better essay than an extravagant one. Make a list of your most meaningful hobbies and consider the following questions:

1) Which hobby on your list have you shown the most commitment to? Which has been most influential in your development?

2) What is the strongest emotion you feel about this hobby?

• Why do you feel this emotion?
• Has that emotional response changed over time? If so, how and why?
• What emotions do you feel during the activity?

3) What thoughts and feelings go through your mind while you participate in this hobby/activity?

4) Have you developed or strengthened any personality traits as a result of this hobby? If so, what are they and how have they evolved over time?

5) Have you developed any skills due to this hobby? These can include soft skills such as critical thinking, public speaking, work ethic, and teamwork, or hard skills, which are specific to whatever domain your hobby is a part of.

6) What impact has this hobby had on the rest of your life? (other activities, social life, academics, etc.)

Once you’ve chosen your hobby, think of how you want to structure your essay. You only have 100 words, which is a very small space to work within, so you’re going to have to be concise. The prompt specifically asks why this interest brings you joy, so you’ll definitely want to include a response to that question. You have some flexibility in the way you answer this question. You might explicitly state what you enjoy about the hobby, or perhaps you’ll talk about some of the activity’s outcomes that have brought you fulfillment.

Consider this response from a hypothetical student:

My fingers pluck each string deliberately but delicately. My foot taps quietly along, keeping rhythm like a metronome. I am at peace, once again practicing classical guitar like I have every day for the past ten years. That seems long already, but there is still so much to learn. As each mellifluous note wafts through the air, I am filled with the joy of knowing there is another technique to master, another piece to play, another obstacle to conquer. Playing classical pieces is more than a hobby; it is a challenge, an opportunity to honor something that transcends time.

This is a strong response for a number of reasons. First, it uses very evocative language to great effect, painting a picture of the hobby in question. Second, it describes in detail the emotions the hobby evokes and the reason it elicits joy in the student. And finally, it showcases the student’s perspective in a way that cannot be misconstrued. This student is clearly intellectually stimulated by this hobby, dedicated to it, and industrious when it comes to practicing – all excellent qualities to bring to Caltech.

You should strive to do the same things in your essay. Use imagery to your advantage, be specific when discussing your emotions, and try to describe your emotional response to the hobby in a way that reveals something about your personality.

You want to craft an effective essay, so you should note a few common mistakes to avoid:

• Don’t pick the wrong activity! Bad activities include: hobbies you’ve already written about somewhere else in your application, impressive-sounding hobbies you don’t actually participate in, and hobbies you haven’t actually put that much time into.

• Don’t just describe the interest without elaborating on its impact on you. You might get caught up in your anecdote when writing, but don’t forget to explain the hobby’s significance.

• Don’t just list your accomplishments within the hobby. You shouldn’t simply provide a list of things that make you look good superficially. You want to show your personal perspective and growth by discussing your emotional response to your chosen hobby and how the hobby impacts your life.

Structurally, take a reflective approach and really analyze your thoughts and feelings about the hobby. Since you only have 100 words to work with, avoid writing more than one anecdote. You need to be concise in your language, but as long as you can provide a good reflection and describe what it is about your hobby that brings you joy, you will be fine.

This prompt is also optional, but it’s a great chance to describe something else you’re passionate about. If you were stuck on the previous prompt, struggling to choose between two hobbies that are really important to you, you can describe the second one here. 

Bear in mind that this prompt has only 50 words, half the words you had for the previous prompt. If you decide to write a response to this prompt, you have to be extremely precise in your word choice. Consult the guide to the previous prompt above and CollegeVine’s guide to writing the extracurricular activities essay for more in-depth tips on how you should craft your essay.

Consider the following example response:

My fingers pluck each string deliberately but delicately. I am at peace, practicing classical guitar like I have daily for the past decade. As notes float through the air, I’m filled with the joy of knowing there is another technique to master, another piece to play, another obstacle to conquer.

This essay is the previous example adapted to fit the smaller word limit. Notice that it still defines the hobby, paints a picture of the activity, and describes the student’s emotional response when participating in the activity. Of course, the reduced word count means that this essay reveals a bit less about the student than the previous version, but it still answers the prompt well.

Where to Get Your Caltech Essay Edited

Do you want feedback on your Caltech essays? After rereading your essays countless times, it can be difficult to evaluate your writing objectively. That’s why we created our free Peer Essay Review tool, where you can get a free review of your essay from another student. You can also improve your own writing skills by reviewing other students’ essays. 

If you want a college admissions expert to review your essay, advisors on CollegeVine have helped students refine their writing and submit successful applications to top schools. Find the right advisor for you to improve your chances of getting into your dream school!