Physics 5 — Modern Physics
E = mc² and half-life
continues from lesson 4 — values defined earlier in the course stay live here
Mass is frozen energy at an outrageous exchange rate. One gram, fully converted:
= ~9×10¹³ J — a city's daily electricity, from a paperclip
Unstable nuclei cash that energy out randomly but statistically on schedule: half are gone every half-life. Carbon-14 (t½ = 5730 y) turns every old object into a clock:
C-14 remaining (%) vs age (years) — measure the fraction, read off the age
✓ pass one half-life, half remains — by definition
That closes the Physics track: motion, momentum, fields, heat, and the modern rules underneath them all.