The Empire State Building: 1,250 feet.

A penny dropped from the top hits you at the bottom.

It feels like a flick on the forehead. "Not even very hard."

That's it. That's the whole crime scene.

You've heard the legend — a penny off a skyscraper falls so far, so fast, it could kill. It's the most famous physics "fact" in America. It's also wrong, and a physicist proved it in the most committed way possible.

Louis Bloomfield at the University of Virginia sent pennies up on helium balloons and stood underneath while they rained back down on him. He ran them through wind tunnels too, but mostly: he took pennies to the head, on purpose. His verdict — it feels like being flicked in the forehead, "but not even very hard."

Here's why. A penny is flat, light, and hopeless in the air. It doesn't knife downward — it tumbles like a leaf, and all that flat face keeps slamming into air molecules. After about 50 feet of falling, drag pushing up balances gravity pulling down, and the penny stops speeding up. That top speed — terminal velocity — is about 25 mph. From 50 feet or 1,250, it arrives the same: slow, fluttering, harmless.

Strip away the air and the story flips: a vacuum-dropped penny would arrive at 208 mph — enough to damage a skull. The atmosphere is doing all the bodyguard work.

Want an actual villain? The ballpoint pen. Dense, streamlined, and stable if it noses over, a pen can come down like a 200 mph dart — Bloomfield says one could chip a sidewalk. Fear the junk drawer, not the piggy bank.

The 10-Second Version: A falling penny tumbles, maxes out near 25 mph within ~50 feet, and lands softer than a flicked finger. Shape — not height — decides how hard things hit.

Source: Scientific American — Could a Penny Dropped Off a Skyscraper Actually Kill You?

Shawn's Footnote

Terminal velocity isn't one fixed number per object — it depends on orientation. A penny falling face-flat has far more drag than one slicing edge-on; real pennies tumble, so ~25 mph is the average of a chaotic flutter. The pen carries an asterisk for the same reason: most pens tumble too, and a tumbling pen is much less scary than a dart-stable one. The quantity that decides everything is weight relative to drag area. And the no-air number is just √(2gh) doing what geometry alone would allow: about 193 mph from the 1,250-foot roof, or the article's 208 mph if you drop it from the tip of the antenna, 1,454 feet up.

Since most of you are opening the year with Motion: all ten Motion warm-ups, with answer keys. One bell-ringer a day for the first two weeks, from "how is your body moving while you sit in that chair" to a bowling ball dropped from an SR-71 that will never reach the speed the equation says. That last one is today's penny, in worksheet form. Editable PowerPoint, print or project.

DOWNLOAD: 10 Motion Warm-Ups, answer keys included

The free-fall opener — one textbook, two sheets of paper, every misconception on the table:

This week's partner: us. The complete Circuits escape room, Case 7, is free: five evidence stations, student worksheets, a 21-page teacher guide, answer keys. Print it tonight, run it tomorrow. Get the free escape room. (If your company sells to physics teachers, this slot is available. Reply to this email.)

That free-fall demo is the opening move of our Motion unit. The Physics Motion Unit Bundle ($32.20) is the rest of it: 13 resources, four editable slide decks, practice assignments, 10 warm-ups, a graphing scavenger hunt, the unit test, answer keys for everything. Your first unit of the year, already planned.

(The air took most of the energy. Classic drag.)

Stay Wildly Curious,

— Lauren & Shawn

Through Sunday, September 14, the code SEPT20 takes 20% off the full-year bundles: CORE, PLUS, or MEGA. MEGA comes to $434 with the code. Purchase orders welcome. Then one quick poll, one click: