https://physics.stemlores.com/2026-10-07 https://physics.stemlores.com/stories/where-does-e-mc2-come-from/2026-10-07https://i.ytimg.com/vi/VG691q_byUE/hq720.jpgWhere Does E=mc² Actually Come From?Where does E=mc² come from? Einstein's 1905 thought experiment with two flashes of light, what the equation says and doesn't, and how it was tested.https://www.youtube.com/embed/VG691q_byUE6182026-10-07T14:00:40+00:00 https://physics.stemlores.com/stories/why-isnt-the-sky-violet/2026-10-06https://i.ytimg.com/vi/ChkF5oVeX6c/hq720.jpgWhy Isn't the Sky Violet?Air scatters violet light even more than blue, so why is the sky blue? Tyndall's artificial sky, Rayleigh's 1/λ⁴ law, our cone cells, and why sunsets turn red.https://www.youtube.com/embed/ChkF5oVeX6c5642026-10-06T14:00:25+00:00 https://physics.stemlores.com/stories/einstein-nobel-photoelectric-effect/2026-10-05https://i.ytimg.com/vi/JuSgKi9SwYw/hq720.jpgThe Experiment Einstein Actually Won His Nobel ForEinstein's Nobel Prize was not for relativity. Why it named the law of the photoelectric effect, and how Millikan, who doubted it, proved the equation.https://www.youtube.com/embed/JuSgKi9SwYw5982026-10-05T14:00:08+00:00 https://physics.stemlores.com/stories/cavendish-experiment-weighing-the-earth/2026-10-04https://i.ytimg.com/vi/f_Oxm2R-joU/oar2.jpgIn 1798, a Man Weighed the Earth From a ShedIn 1798 Henry Cavendish weighed the Earth: lead balls, a twisting wire and a telescope gave its density as 5.448 times water’s. Today’s value is 5.514.https://www.youtube.com/embed/f_Oxm2R-joU2026-10-04T16:00:05+00:00 https://physics.stemlores.com/stories/gps-relativity-38-microseconds/2026-10-04https://i.ytimg.com/vi/R8DvY_mj2FY/oar2.jpgWithout Einstein, Your GPS Would Drift 10 km a DayGPS satellite clocks gain about 38 microseconds a day because of relativity. Uncorrected, your position would drift about 10 km a day. Here is why.https://www.youtube.com/embed/R8DvY_mj2FY2026-10-04T13:07:19+00:00 https://physics.stemlores.com/stories/why-137-haunts-physics/2026-10-04https://i.ytimg.com/vi/wF0yxnKh9es/hq720.jpgWhy Does the Number 137 Haunt Physics?Why is the fine-structure constant so close to 1/137? How Sommerfeld found it in 1916, why it has no units, who tried to explain it, and what we measure now.https://www.youtube.com/embed/wF0yxnKh9es5922026-10-04T09:26:21+00:00 https://physics.stemlores.com/stories/feynman-137-on-the-wall/2026-10-04https://i.ytimg.com/vi/Ev9QKuAJzZI/oar2.jpgWhy Feynman Told Physicists to Hang 137 on the WallWhy did Richard Feynman say good physicists put 1/137 on their wall? What the fine-structure constant is, why it has no units, and why nobody can explain it.https://www.youtube.com/embed/Ev9QKuAJzZI2026-10-02T07:19:44+00:00