30 day learning challenge: 31 ideas, one a day

By the edgi team Updated November 4, 2026

A 30 day learning challenge works best as one odd idea a day, and edgi has the month ready: 31 short interactive Lessons in a free iPhone app, listed below one per day, with Day 1 playable on this page. Each Lesson walks you through one idea and makes you play with it (you predict, you tap, you test), then it ends with a card that lands on a Map of what you know.

We make edgi, and we'd rather hand you 31 ideas than 31 topics to go and look up.

The list runs 31 days so it fills a long month. Doing 30? Then Day 31 is a bonus, and it's the one about why a new habit takes longer than 21 days.

Day 1, right here

You're on an old shore, making paint from what you find. Red clay grinds to red paint. A blue jay feather grinds to dull brown, and a glass dipped in the blue sea comes up clear. Then you find out which color languages name last.

Blue Blue is light with wavelengths between 450 and 495 nanometers.

60-second Lesson

Blue

Most languages name blue after red, green and yellow. Blue was the sky and the sea, almost never a thing you could hold.

Play it here Read about blue

The 31 days

• Day 1: Blue. Most languages name blue after red, green and yellow, and one explanation is that you could rarely hold it.
• Day 2: Bioluminescence. Life invented its own light at least 94 separate times.
• Day 3: Instant noodles. Frying the cooked noodle leaves tiny holes, so hot water fills it back up in three minutes.
• Day 4: Gravitational time dilation. Your head ages faster than your feet, and a GPS clock gains time every day.
• Day 5: Tulip mania. Dutch traders paid more and more for promises of tulip bulbs still in the ground, until buyers stopped coming.
• Day 6: Human echolocation. A click's echo tells you how far and how hard things are, and people can learn it.
• Day 7: Slot machines. The reels are an animation. The computer picked your result before the first one moved.
• Day 8: Convergent evolution. A dolphin is closer kin to a hippo than a shark, but fast swimming gave both one shape.
• Day 9: Loanwords. Tea that went overland is called chai. Tea that came by Dutch ship is called tea.
• Day 10: GPS. Your phone finds itself by timing radio signals from satellites.
• Day 11: The Cavendish banana. Every Cavendish banana is a clone, so one fungus can kill them all.
• Day 12: Inattentional blindness. About half of viewers missed a gorilla walking past, and so did 20 of 24 radiologists.
• Day 13: Aluminum. It is the most common metal in the ground, yet it once cost more than gold, because it grips oxygen so hard.
• Day 14: Saltstraumen. A 40 km fjord fills and empties through a 150 m gap: one of the world's strongest tidal currents.
• Day 15: Why onions make you cry. An onion makes its stinging gas only when cut, and it needs a second enzyme to do it.
• Day 16: The Monty Hall problem. Switching doors wins the car 2 times in 3, because the host never opens the door with the car.
• Day 17: Norse mythology. Nearly everything we know about the Norse gods was written down by Christians in Iceland.
• Day 18: The Fermi paradox. One civilization spreading slowly would fill the galaxy, so why is the sky empty?
• Day 19: Pointillism. Seurat's grass is dots of separate colors, and your eye mixes them. Stirred paint would go darker.
• Day 20: Caffeine. It gives you no energy. It blocks the locks adenosine uses to make you sleepy.
• Day 21: Earworms. An earworm is your inner voice replaying a scrap of song, and chewing gum can quiet one.
• Day 22: Carcinization. Crab shape has evolved at least five separate times.
• Day 23: Etymology. Muscle once meant little mouse, but no old writing shows a Roman paid in salt.
• Day 24: Stained glass. The paint only takes light away. The picture is the light behind it.
• Day 25: Compound interest. Your interest earns interest, so at about 7% a year, starting 10 years sooner does what twice the money does.
• Day 26: The nasal cycle. You breathe mostly through one nostril at a time, and every couple of hours the sides swap.
• Day 27: The testing effect. Pulling something out of memory makes it last longer than reading it again.
• Day 28: Catching up in orbit. A lower orbit is a faster lap, so to catch a ship ahead, you slow down and drop below it.
• Day 29: Insect flight. A bee beats its wings 200 times a second by shaking its chest.
• Day 30: Sourdough. Wild yeast make the gas that lifts the bread, and bacteria make the acid that sours it.
• Day 31: Habit. In one study, a new daily habit took the middle volunteer 66 days to feel automatic, not 21.

No two days in a row come from the same field. Language sits next to animals, money next to the body, art next to space, so the month never settles into one subject long enough to feel like a course.

A month of ideas, not homework

When we asked ChatGPT for a 30 day challenge to learn something new, it gave us 30 one-line topics ("the night sky", "a knot"), about 15 to 30 minutes a day, and a prompt to write down one thing from the day. Most pages we found for the phrase are the other kind: one skill practiced every day, and one of them schedules sessions of up to 90 minutes. The table leaves the research to you. By the fourth evening you're deciding what "the night sky" is supposed to mean, and that's where the month dies.

Here each day is the idea itself, already explained, and you play it instead of looking it up. A Story Lesson in edgi takes a median of 90 seconds and an Interactive Lesson 141, and there's nothing to write down after. Every Lesson you finish becomes a card on your Map, beside the ideas it connects to. Some days connect to each other too: Day 4 and Day 10 turn out to be about the same satellite clocks.

Miss a day and play the next one; the list has no dates on it. Day 31 is the Lesson for that moment: in the habit study behind it, a missed day barely set anyone back.

If a day isn't yours, swap it: make a Lesson, Quiz or Explainer on a topic you type. And if the month is a New Year's resolution, here's why one idea beats one skill.

Pick something else only if…

• You want to practice one skill for 30 days: Learn30 or Topicly builds a plan for a goal you name.
• You want a tracker for a challenge of your own: LockIn30.
• You want a language: Duolingo.
• You need Android. edgi's Lessons play in a browser at edgi.tv/learn.

FAQ

What is a 30 day learning challenge? Learning something new every day for a month. Most versions pick one skill or hand you a table of topics to research; this one is 31 ideas, each a short Lesson in edgi, listed on this page.

What can I learn in 30 days? A month of single ideas, from why languages named blue so late to why switching doors wins at Monty Hall and how a bee beats its wings 200 times a second. Each is a short Lesson in edgi, and each one you finish becomes a card.

How do I learn something new every day? Have tomorrow's idea picked before tomorrow comes, so there's nothing to choose when you sit down. This list does that for a month, and the longer answer is on the best app to learn something new every day.

Is there an app for a 30 day learning challenge? edgi. It's a free iPhone app of short interactive Lessons, every idea you finish becomes a card on your Map, and the 31 days on this page are ready to play.

What if I miss a day? Play the next one, or go back for the one you missed; the list has no dates. In the habit study behind Day 31, a missed day barely set anyone back.

How long should I spend learning each day? The challenges we found ask for 15 to 90 minutes a day. One idea needs less: a Story Lesson in edgi takes a median of 90 seconds, an Interactive one 141.

Is edgi free? Yes. edgi is free: Lessons, cards, Sets and the Map.

Is edgi on Android? Not as an app. edgi runs on iPhone, and its Lessons play in a browser at edgi.tv/learn.