Classic Lab Experiments Pixel Sticker Sheet

12 pixel-art physics stickers on one A5 (5.83″ × 8.27″) white kiss-cut sheet: Classic Lab Experiments. Every character below has its own sticker page with the full physics panel.

Wimsha

In the early 1880s James Wimshurst, a London shipwright and amateur experimenter, perfected an influence machine: two insulating discs carrying metal sectors, turned in opposite directions on one axle. Neutralising brushes and collecting combs let a tiny starting charge on one disc induce opposite charge on the other, over and over, so the charge grows with each turn. No rubbing is involved, so unlike older friction machines it works reliably in damp weather and starts itself.

Q grows by induction each turn
Q: charge stored on the collectors, usually Leyden jars (C); V = Q/C: voltage across the spark gap (V)

Jumpring

In 1887 Elihu Thomson showed that a metal ring slipped over the iron core of a coil leaps into the air when AC is switched on. The changing flux induces a current in the ring; by Lenz's law it opposes the change, and because the ring current lags behind, the net force on average pushes the ring away. With steady AC a ring can float.

F ∝ −I_coil I_ring
I_coil: current in the coil (A); I_ring: induced current in the ring (A)

Meldea

Around 1859 Franz Melde tied a string to the prong of a tuning fork and pulled it taut (Ann. Phys. 185, 193, 1860). At the right tensions the string broke into steady standing waves, with nodes that stood still and loops that blurred. Change the tension and the number of loops jumps.

f = n√(T/μ)/(2L)
f: frequency of the string vibration (Hz); n: number of loops; T: tension (N); μ: mass per unit length (kg/m); L: length of the string (m)

Ruchardta

In 1929 Eduard Rüchardt measured the heat-capacity ratio of a gas with a simple trick (Phys. Z. 30, 58). A ball fits snugly in the neck of a large flask. Push it and it bounces up and down on the springy gas below. The squeezes are quick, so no heat flows and the gas acts adiabatically. Timing the oscillation gives γ.

γ = 4π²mV/(A²pT²)
γ: ratio of heat capacities C_p/C_v; m: mass of the ball (kg); V: volume of gas (m³); A: cross-section of the neck (m²); p: gas pressure under the ball (Pa); T: oscillation period (s)

Paddlewheel

James Prescott Joule let weights fall on pulleys, turning a paddle wheel inside an insulated vessel of water. Friction of the paddles warmed the water a tiny amount. Dividing the work done by the falling weights by the heat produced, he reported in 1850 (“On the Mechanical Equivalent of Heat”, Phil. Trans. R. Soc. 140, 61) that 772 foot-pounds of work raise one pound of water by 1 °F.

W = J Q
W: mechanical work (ft·lbf); J: mechanical equivalent of heat (ft·lbf per BTU); Q: heat produced (BTU)

Radiometra

A Crookes radiometer has four vanes, each black on one side and silver on the other, inside a bulb pumped down to a partial vacuum. In light, the vanes spin with the dark sides retreating. If light pressure drove it, the reflective sides would be pushed harder (a reflected photon gives twice the push of an absorbed one) and it would spin the other way. Instead, the dark side gets warmer, and the thin gas does the work. James Clerk Maxwell (Phil. Trans. R. Soc. 170, 231, 1879) and Osborne Reynolds, in his study of thermal transpiration (Phil. Trans. R. Soc. 170, 727, 1879), explained it: gas creeps around each vane's edge from the cold side to the hot side, and the reaction pushes the vane towards its cooler, silver side.

dark side warmer ⇒ vane moves dark side trailing
dark side: absorbs light and heats up; silver side: reflects light and stays cooler; gas: thin enough for molecules to travel far between collisions, but not a hard vacuum

Galvana

William Thomson, later Lord Kelvin, developed the mirror galvanometer around the 1858 transatlantic telegraph cable, whose signals were too faint for ordinary needles. A tiny mirror carrying small magnets hangs inside a coil; a current twists it slightly, and a beam of light reflected from it sweeps across a scale. By the law of reflection, turning a mirror by an angle θ turns the reflected beam by twice that angle.

beam deflection = 2θ
θ: rotation angle of the mirror (rad); 2θ: rotation angle of the reflected beam (rad)

Rowlanda

In 1876, in Helmholtz's Berlin laboratory, Henry Rowland charged an ebonite disc and spun it fast. A magnetic needle nearby deflected (Am. J. Sci. 15, 30, 1878). A moving charge makes a magnetic field, just as a current in a wire does: current is charge in motion.

B ∝ q v
B: magnetic field near the disc (T); q: charge on the disc (C); v: rim speed (m/s)

Inertix

Spin a coil of wire fast and stop it suddenly: the free charges inside keep going for a moment, like passengers in a braking bus, and a pulse of current flows. Richard Tolman and Thomas Stewart measured it in 1916 (Phys. Rev. 8, 97). From the charge that flowed they got the carriers' charge-to-mass ratio, close to that of the electron, showing that current in metals is carried by electrons.

Q = (m/e) v₀ L / R
Q: charge that flows after stopping (C); m/e: mass-to-charge ratio of the carriers (kg/C); v₀: rim speed of the wire before stopping (m/s); L: length of the wire (m); R: resistance of the coil (Ω)

Hemisphera

Otto von Guericke, mayor of Magdeburg, invented an air pump and in 1654 demonstrated it at Regensburg before the Imperial Diet. He fitted two copper hemispheres together and pumped the air out. With the inside nearly empty, the outside air pressed them together so hard that teams of horses could not pull them apart. Let the air back in, and they fell apart by hand.

F = πr²Δp
F: force needed to pull the hemispheres apart (N); r: radius of the hemispheres (m); Δp: pressure difference, outside minus inside (Pa)

Quincka

In 1896 Georg Quincke saw that an insulating sphere in an oil, placed in a strong steady electric field, can start spinning on its own. Charges pile up on its surface; above a threshold field the arrangement is unstable and a small tilt grows into steady rotation.

E > E_c → rotation
E: applied DC electric field (V/m); E_c: threshold field for spontaneous rotation (V/m)

Gravitas

G sets the strength of gravity between any two masses. It is measured with torsion balances (Cavendish, 1798) and other lab methods, where the pull between kilogram-scale masses is about 10⁻⁷ N or less.

G = 6.674 30(15) × 10⁻¹¹ m³ kg⁻¹ s⁻²
G: Newtonian constant of gravitation; (15): standard uncertainty in the last two digits, 2.2 × 10⁻⁵ relative