How to Write the Caltech Supplemental Essays: Examples + Guide 2021/2022

Caltech wants a bright, curious, independent student body. It’s looking for intellectual vitality, and this essay is your opportunity to show that side of yourself. No matter what you choose to write about, make sure:

  1. Your topic genuinely piques your curiosity. Don’t pick something just because you think Caltech will like it. Genuine interest is both easy to write about and hard to fake! 

  2. You’ve really explored the topic. Imagine you’re at a dinner party—could you talk about it confidently, off the cuff? 

  3. Think about things that have inspired you to go down research rabbit holes, that have motivated you to take action, or that have enhanced your understanding of some other subject.

Note that this prompt has Super Essay potential! Many schools (Stanford, for one) ask some version of this question. Look closely at your other supplemental prompts and write strategically.

Another common prompt that’s somewhat related is the “think about a time when your beliefs were challenged by a perspective other than your own” essay. If you know you have to write that essay somewhere down the line, take that into consideration as you formulate your topic. 

Last thing: You have three things you can write about. 

  1. Life Situation: This is a flexible definition that could include, among many other things, an encounter with a fascinating individual, a museum exhibit that moved you, a service experience, volunteering for a political campaign, a summer job; or a family tradition. 

  2. Media Story: This one’s pretty straightforward and may offer the “easiest” way into the topic. Have you read any shocking statistics that have inspired you to care about a cause or social issue? Any exciting developments in a STEM field? A human interest story or profile of someone who inspires you? Feel free to comb through your favorite websites or publications for inspiration! 

  3. Topic: Similarly open-ended, the key here is specificity. Rather than choosing a broad subject like politics, identify an idea that falls under that umbrella, like nudge theory. Instead of math, try chaos theory. The more specific and uncommon, the better!

Here’s an example that does an effective job of answering this prompt.


When I was doing customer research for my chemistry practice website, I came across another, much larger issue with education: the lack of personalized learning. It stuck with me. I knew if I could create a solution, I would be helping many students, like my friends, reach their goals. Also, the idea of an engine that can recommend lessons based on your learning style just seemed super cool. As I dug deeper into the issue, I realized I didn’t have the skills to even scratch the surface. So I started developing what I needed to build a system that recommends lessons based on learning style.

On my own time, I learned about machine learning algorithms, from linear regressions to k-nearest neighbor classifiers, and whenever I could I applied these skills on mini research projects—finding trends, then using data to create an algorithm that predicts other data. At school, I took a rigorous machine learning course where one of my final projects was using data from Portuguese schools to analyze what factors lead to good grades. 

Looking ahead, I’m hoping to study computational neuroscience to properly know how the brain solidifies connections and recalls information. With the two together, I could create a model of how a person learns based on different stimuli, and recommend different lessons based on the stimuli. I still have quite a bit to learn, but if I manage it, it could have a powerful impact on the educations of students around the world. (247 words)

— — —

Tips + Analysis

  1. Identify the topic: As you may know by now, we’re huge fans of getting straight to the point in these shorter supplements. Notice how this student identifies his topic in two steps: first by identifying the broad field of education, then zooming in on the lack of personalized learning. Right off the bat, the writer has “set up the dominoes,” so to speak. This helps both reader and writer. 

  2. Problematize it: Notice how the topic at hand is not merely an interesting subject, but a problem the student wants to tackle (it’s never a bad idea to ground your supplements in a larger Purpose—this is especially true of “Why Major?” essays). Better still, this student has chosen a problem that he’s already taken steps to address (i.e., the “delve more deeply” part of the prompt). 

  3. Use an extracurricular: We love how this student used this essay as an opportunity to elaborate on an extracurricular: building a chemistry practice website. If this prompt stumps you, look to your Activities List for inspiration!

  4. Focus on the future: What takes this essay to the next level is the final paragraph. The student is doing two things: 1) transforming the issue (impersonal education) into a learning goal (“how the brain solidifies connections and recalls information”) and an action item (“[creating] a model of a how a person learns based on different stimuli, and recommend different lessons based on the stimuli”); and 2) stating a professional goal—make a “powerful impact on the education of students around the world.” This is a high-level maneuver and an inspiring way to stick the landing, so to speak. 

Here’s a bonus example, written for Stanford’s “what gets you excited about learning” prompt, that could have also worked well for this Caltech prompt.

Bonus example:

I am fascinated by patterns. Learning the art of writing Chinese characters taught me to pay attention to a pattern’s reference points, where deeper meaning lies. My favorite character, XIAO, from the word XIAOSHUN, visualizes a central tenet of Confucianism: the lifelong supporting relationship between parent and child. The top part, LAO, means old. The bottom part, ZI, means son. Mandarin, like many other ancient languages, provides a code of behavior. 

During quarantine, I enrolled in IBM’s AI For Everyone and Harvard’s CS50 on edX and traveled down a TED rabbit hole. While intriguing to learn that each emoji is made up of patterns like this: 11111011000000010, I was captured by the human applications technology like AI provides. With AI’s pending impacts worldwide, I feel driven to ensure society doesn’t experience potentially harmful implications of technology. 

How do we embed universally ethical reference points in algorithms for AI to exhibit empathy, recognizing XIAO encourages a relationship of support? 

Humans and machines have processing limitations. In his research paper, Linguistics Professor John Whitman taught me that grammar, typically regionally similar, immensely influences humans’ cognition abilities. AI’s applications will be universal, so likewise, its grammar or code must be universal. By learning how people segment information and optimizing this cross-cultural data in a beneficial way, algorithms’ limitations will be reduced. If ethically structured, AI will inherently learn to reflect moral behaviors. 

While it’s a big task to construct an ethical and empathetic AI, I believe I will find the tools at Stanford. (250 words)

— — —

Leave a Reply

Your email address will not be published. Required fields are marked *