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3Blue1Brown builds toy SIR models to simulate how an epidemic spreads and tests scenarios like social distancing, travel restrictions, central gathering places and quarantine. It was made during the early COVID-19 outbreak.

Technology Connections explains how the simple American drip coffee maker works, including the bimetal valve and bubble-pump heating, and compares the original Mr. Coffee with modern machines.

Technology Connections explains why electric kettles are uncommon in the US, centering on 120V circuits limiting power. He tests ways of boiling water on gas, electric ranges and kettles.

James Hoffmann explains how decaf coffee is made, how the decaffeination processes differ, and why decaf is roasted and stales differently. He also discusses decaf quality and health questions.

Terence Tao and Grant Sanderson of 3Blue1Brown walk through the cosmic distance ladder, showing how humans measured distances from the Earth to the Moon, Sun, planets and beyond. It includes animations and the history behind each step.

Numberphile talks with Grant Sanderson of 3Blue1Brown about a darts puzzle with a shrinking bullseye. Solving it takes the volumes of high-dimensional spheres, and the answer turns up Euler's number.

Not Just Bikes looks at traffic in the Bahamas to show that a small country can be just as car-centric as a big one. He ties it to land use, car dependence and how dedicated transit lanes help.