units

Veritasium explains that the US signed the Metre Convention in 1875 and that all US customary units are officially defined in terms of metric standards. It also touches on the standard kilogram.

Veritasium explains the effort to redefine the kilogram, which was still defined by a physical artifact, and how a near-perfect silicon sphere from the Avogadro project helps. It also covers the history of the unit's odd naming.

Tom Scott investigates the claim that the microwave was invented to heat hamsters, and interviews James Lovelock about freezing and microwave-thawing hamsters in the 1950s. It traces early magnetron uses beyond radar.

Veritasium visits NIST to explain Standard Reference Materials, the carefully characterized items such as peanut butter used to calibrate instruments and keep measurements consistent. It covers why they exist and why they are expensive.

Veritasium explains why the kilogram is being redefined in terms of Planck's constant rather than a physical metal artifact. It visits NIST to show the Kibble balance and why measuring mass precisely is hard.

Adam Savage shows a set of Mitutoyo ceramic gauge blocks and uses them to explain metrology, the science of measurement. He argues that accuracy and precision work differently than most people assume, which changes how you think about every measuring tool.

CGP Grey explains the elegant ratio of A4 and the metric paper sizes, then zooms out across scales from the Planck length to the observable universe.

CGP Grey explains the mess of Daylight Saving Time, including its dubious energy savings and the odd cases like Arizona that opt out. It is a short, simple explainer.

Tom Scott follows the ISO 3103 / BS 6008 standard to make an international standard cup of tea, using specialist tasting equipment. The video shows how precisely the standard is specified.

Technology Connections explains the difference between power (watts) and energy (watt-hours) and why confusing them leads to errors. It runs about 52 minutes and uses everyday examples.

Technology Connections explains why single-hose portable air conditioners are inefficient and often a poor choice compared with window units. It details how the single hose pulls in warm outside air and wastes energy.

Numberphile's James Grime discusses highly composite numbers, nicknamed anti-primes, which have more factors than any smaller number, using 5040 as the central example. It touches on Plato and Ramanujan.

Technology Connections explains how refrigerator and freezer design affects energy use, using chest freezers to show why top-opening designs and layout choices matter. It includes thermal-camera footage of cold air spilling out of upright units.