It makes sense that metrication,2 when left to its own devices, takes forever (150 years and counting in America). The point of units is to standardize quantification, so it’s natural to resist changing to a unit you don’t intuitively understand.
SI is already used for everything electrical (Volts, Amps, Coulombs, Ohms, Farads, and Tesla), so this post attempts to come up with some useful mnemonics for units where the English equivalents die hard.
| Parameter | Example | Mnemonic |
|---|---|---|
| Length | 1 m | Distance from the floor to somewhere between the doorknob and the deadbolt |
| 10,000 km | One-quarter of the way around the earth | |
| Speed | 100 km/hr | Speed limit on most city freeways |
| 10 km/s | Low-Earth Orbit | |
| 0.3 Gm/s | The speed of light in a vacuum. Let’s be honest, no one uses gigameters as a unit, but they should. | |
| Acceleration | 9.81 m/s² | Acceleration due to gravity on surface of Earth |
| Volume | 2 L | Giant bottle of soda. The familiarity most people have with liters is kind of case-in-point for how Metrication is easy once people have an intuitive feeling for the size of a unit. |
| Mass | 2 kg | The mass of that bottle of soda |
| 2,000 kg | Mid-size truck | |
| Force | 1 kN | Weight of an average NFL quarterback standing on your chest |
| 1 MN | Thrust of the engines on a Boeing 777 | |
| Pressure | 100 kPa | Atmospheric pressure at sea-level1 |
| Energy | 1 J | Work required to lift a tennis ball up to your head |
| 10 kJ | Energy stored in a AA battery | |
| 1 MJ | Caloric energy in a package of M&Ms | |
| Power | 1 kW | Moderately sized microwave oven |
| 1 MW | Power supplied by the engine in the fastest super cars | |
| 2 GW | Hoover Dam |