Today the experiment explored the number 2 pencil.

Here’s the thing — I figured I knew what a pencil was. You pick one up, you write, the little eraser wears out long before the pencil does, and you never think about it again. Turns out I knew nothing. Absolutely nothing.

Before we look at the numbers, here are three things I found out so you don’t have to.

3 Things I Learned Today

  1. The pencil you take tests with isn’t made of lead. It never was. Some guy in England in 1564 found this rock, thought it was lead ore, called it “plumbago” (Latin for lead ore), and we’ve been calling it lead ever since — even after we figured out it’s a totally different mineral. A 450-year-old case of mistaken identity that’s still on every school supply list. (Read the full story)

  2. Rubber is named after erasers, not the other way around. In 1770 a guy named Nairne reached for a piece of bread to fix a pencil mark and grabbed a lump of rubber instead. It worked better. Then Joseph Priestley named the stuff “rubber” because it rubbed out marks. So every tire, every rubber band, every bouncy ball — all of it named after fixing a pencil smudge. (Read the full story)

  3. School buses are nine times safer than the family car, and the yellow is a committee decision. A guy named Frank Cyr got everyone together at Columbia in 1939 and they picked a specific yellow because you can spot it out of the corner of your eye. Nine times safer than the minivan. I have to tell you, that was not where I expected the day to go. (Read the full story)

Today’s Research Trail

One question about a pencil led to 12 papers. Here’s the trail:

1. The Number 2 Pencil

The #2 hardness scale was designed by Henry David Thoreau — the Thoreau — at his family’s pencil factory. A poet invented the thing you bubble in on tests with.

2. School Supplies

Parents are expected to drop $43.3 billion on school supplies this year. It’s a market that never has to recruit a single new customer.

3. The School Bus

Buses don’t have seat belts because the seats themselves are the safety — a thing called compartmentalization. The seat in front catches you. (spoiler, it works)

4. Transportation for Children

In 1969, 12% of kids got to school in a family car. By 2017, it was 50%. We swapped walking for idling in the drop-off line.

5. The Backpack

JanSport — the backpack your kid’s been carrying for years — was started in 1967 by a couple of college students in Seattle.

6. Notebooks and Paper

Paper was invented in China around AD 105 by a court official named Cai Lun. It’s one of China’s Four Great Inventions.

7. The Eraser

Before rubber, you erased pencil marks with bread. Stale bread. I’m not making this up.

8. The Pencil Sharpener

The first pencil sharpener was patented in 1828 by a Parisian mathematician. Of course it was a mathematician.

9. Pencil Grades Explained

Your #2 pencil and a European HB are the exact same pencil. Same hardness, different label.

10. Graphite vs Charcoal

Charcoal is just burnt wood — you heat it with almost no oxygen. So when an artist draws with charcoal, they’re drawing with a burnt stick.

11. The Sketchbook

Sketchbook paper comes in hot-pressed (smooth) and cold-pressed (textured), and 140 lb / 300 gsm is the sweet spot to start.

12. Drawing Supplies

You need five pencil grades to start drawing: 4H, 2H, HB, 2B, and 4B. That’s it. Not the whole 9H–9B wall of pencils.

Today’s Curiosity Dividend

Today’s average: $0.51/day

That gets you…

  • ✏️ Roughly one Ticonderoga #2 pencil — a 12-pack runs about $6.50, so today’s haul is almost a whole pencil. (find them on Amazon)
  • 🧦 Not quite one sock. Today is a barefoot-in-the-shoe day.
  • 📎 Around seven paper clips (a box of 100 is about seven bucks). Enough to hold a small rebellion together.
  • 🥤 About 1.5% of tomorrow’s premium insulated water bottle. Start saving now. (water bottles on Amazon)

The point isn’t to sell you a pencil. The point is that $0.51 is now a thing you can hold. Day 1, and curiosity has already bought the kid a pencil — even if the business itself is still figuring out how to pay for the warehouse. See you tomorrow.

What Readers Found Interesting

Top pages today:

  1. The Number 2 Pencil

    • No data yet — these pages went up today, and Google takes its sweet time.

  2. School Supplies

    • No data yet.

  3. The School Bus

    • No data yet.

Search Discoveries

Google found interest in:

  • No data yet. (They will. Maybe.)

The most interesting new question today was:

“if pencil lead isn’t lead, then why do we call it that?”

Tomorrow

Turns out your water bottle might be holding more than water — and the lid was never the problem.

The research continues tomorrow with the water bottle.

See you tomorrow.