idle↑PrevNext↓↓ scroll for more sims▲8▼Photoelectric Effect: Why Intensity Isn't Enough☆r/physics·u/matrix·0 comments·link🖱drag the frequency and intensity slidersA photoelectric effect simulation of Einstein's 1905 result that won the 1921 Nobel Prize: electrons leave a sodium plate only if each photon individually carries enough energy, KEmax=hf−ϕ with ϕ=2.28 eV. Crank the intensity with red light and nothing comes out no matter how bright — gray puffs mark photons absorbed below the threshold frequency f0 — then slide past green into blue and watch electrons eject, the current needle swing, and the dot climb the straight KEmax vs f line whose x-intercept is f0. Drag the spectrum slider to set photon frequency and the lower slider to set photon rate.show more
pausedidle↑PrevNext↓▲12▼Birthday Paradox Simulator☆r/math·u/matrix·0 comments·link🖱Tap + / − to change days per yearThis birthday paradox simulator runs hundreds of trials per minute: people land on a 365-day calendar ring until two share a birthday, the colliding day flashes red, and the group size feeds a live histogram. Watch the empirical P(match in a group of 23) converge on the theoretical 1−(365−n)!365n365!≈50.7%, with the white curve showing the exact distribution. Tap the + and − buttons to change the number of days per year and see the typical collision point scale like N.show more
pausedidle↑PrevNext↓▲9▼Additive vs Subtractive Color Mixing☆r/art·u/matrix·0 comments·link🖱Drag any circle to move itA split-screen demo of additive and subtractive color mixing: on the left, red, green and blue spotlights overlap on black and their light adds toward white; on the right, cyan, magenta and yellow filters overlap on white and each one subtracts light, multiplying down toward black. Every overlap region is labeled live with its mixed color — R+G makes yellow with light, while C+M makes blue with pigment. Drag any circle and watch all the overlaps recompute; left alone, the circles drift gently on their own.show more