​

Hey Reader!

I've got a special edition of the newsletter for you today.

Last week marked the 100th edition of Today You Should Know. That's 100 questions about how the world works and 100 answers that I've researched and written for you and me. Wow!

To celebrate this milestone, I thought it might be fun to pick out a few notable newsletters, in a superlative awards style. I also included some behind-the-scenes notes.

Without further ado, here are seven noteworthy newsletters.

🎶 Most challenging to write: Why does musical harmony sound good?

I love music. I love listening to it, I love playing it, and I've even written some myself. But good heavens, music theory can get complicated.

I spent at least three hours just trying to read and wrap my mind around the math of harmony before shelving the newsletter entirely. I finally worked up the courage to pick it back up months later to try to tackle it with fresh eyes.

When I do these newsletters, it's usually the research and outlining that takes up the most amount of time. Some topics go super deep and in many directions, and the biggest challenge becomes how to simplify it in a way that explains enough without complicating things. This question was the most satisfying to finish because of how long that process took!

🪟 Most surprised that other people also found it interesting: What is tempered glass?

I almost didn't write this one because I was worried that people would find the topic to be a bore. Boy, was I wrong!

At the time I wrote this, getting four email replies was a new record! I was tickled pink that my fellow nerds wanted to dig into something as seemingly dry as materials science.

🌌 Most successful on Google: How can we see the Milky Way if we are in it?

This was the second reader-submitted question I ever tackled (thanks again to Bill for the suggestion!). Bill was certainly not alone in his curiosity with our place and perspective of the Milky Way. This article has received over 7,000 clicks on Google Search since I published it back in January 2023.

🪢 Most stressful to write: What is quantum entanglement?

I did this to myself. 😅

For the first year of running this newsletter, I never had a good writing schedule. This meant I usually wrote the newsletter the week leading up to it sending, often finishing it the night before. Now I work on my newsletter pretty much every morning, which allows me to build a buffer in case I need to take some time for myself while still keeping to my Friday schedule that I promise all of you.

But back in April 2023, I decided for some insane reason to choose my most difficult topic yet at a time when I was preparing to move and it was my birthday to boot! While I gifted myself enlightenment about entanglement, I was a bit of a frantic mess this week.

That being said, I did really enjoy how it turned out. This was one of the first newsletters that I decided to create my own graphics to illustrate the answer.

🚴 Favorite graphics: Why is it easier to balance on a moving bike?

I create my own graphics when a mental visual helps an idea click in my head, but I can't find an existing image to illustrate it. It's just me and basic Figma skills putting these together, but somehow it works!

When I was researching this newsletter, I found that articles kept referencing a motion of how one balances on a bike, but I had to act it out in my kitchen while cooking dinner for it to really sink in (true story). So it made sense to create my own illustrations to explain it. My thinking is, if it helps me understand it, it'll probably help someone else too.

By the way, thanks to my dad, an excellent cyclist, for the question submission!

🌇 The one I got wrong: Why does the sky turn pink at sunset?

As Lucas, a commenter on my website, pointed out, my original article on this question was wrong! I said blue wavelength was "high", which is not only wrong, but a confusing way to describe it. Blue wavelengths are best described as short. I was getting things confused with how we talk about frequencies rather than wavelengths.

I was grateful to Lucas critiquing the way I wrote this article and quickly fixed it for future readers. Nowadays, I actually run my newsletter drafts through ChatGPT and ask it to ruthlessly check my writing for scientific accuracy and writing clarity. I never have ChatGPT research or write this newsletter, but it has helped catch some inaccuracies before I hit send.

And thanks to Kayli for the question submission! Sorry I got it wrong the first time. 😬

🔌 My personal favorite: Why does electricity make noise?

This is my favorite because it was something I wondered for years and never looked into until I decided to write this newsletter.

​I hiked the Pacific Crest Trail back in 2017, and I remember walking under some power lines in Oregon. I found it interesting that the hum and buzz of the power lines sounded so similar to the sounds of insects droning on. I didn't know enough about electricity to formulate a hypothesis, so at the time I left it as a mystery.

Now every time I walk or bike by some power lines, I feel satisfied knowing there's a simple reason why we can hear the buzz!

​
The cycle of curiosity from day-to-day life to expanding my knowledge of the world is precisely why I started this newsletter in the first place.

It's truly such a joy to share my curiosity with all of you. So thank you for being curious and joining me for a dollop of learning each Friday. I'm looking forward to delivering you the next 100 questions and answers!

--- Thanks for reading this week's newsletter! If you have any thoughts, questions, or favorite GIFs, my inbox is always open. Just hit reply to send me a note! :) ​ All my best, Caitlin ​Click here to read five facts about Caitlin​

​

P.S. Please keep the great questions coming! Submit your question here or just reply to this email.

P.P.S. I'm curious if you've had a favorite newsletter! Let me know by replying to this email. A friendly nerd is waiting for you on the other side. 👋

​