SortStack #473 — 2027-09-25

By duration · Order from shortest to longest.

1. A car airbag inflating after a crash 30 ms

   The bag must fully inflate before your head arrives — roughly ten times faster than the blink of an eye, driven by a controlled chemical explosion.

2. One full revolution of a helicopter's main rotor 150 ms

   Main rotors spin at only a few hundred rpm, but the blade tips travel so fast they approach the speed of sound — the source of that thudding chop.

3. One human heartbeat at rest 798 ms

   Your heart beats roughly 100,000 times a day and around 3 billion times in a lifetime, pumping enough blood to fill an Olympic pool several times over.

4. An amber traffic light before it turns red 4 sec

   Amber phases are tuned to road speed — typically 3 seconds in town and up to 6 on fast roads, calculated from braking distance physics.

5. The Edinburgh Festival Fringe 25 days

   The world's largest arts festival stages over 3,000 shows — by ticket sales it trails only the Olympics and the football World Cup.

6. How long the Parthenon has been standing 2.5K years

   It survived largely intact for over 2,000 years — until 1687, when a Venetian shell hit the gunpowder the Ottomans had stored inside.

← All puzzles · Play today’s SortStack