How to play Powers-of-Ten Probe
- Choose a trip. Read the distance d and the speed v with their prefixes.
- Convert both to base units with the prefix table, then compute t = d ÷ v.
- Enter the coefficient a and the exponent n. The readout also shows your time with a prefix.
- Press Play. Zoom the ruler to compare the trip with familiar sizes, and check your prediction at arrival.
Prefixes are powers of ten
Each SI prefix multiplies a unit by a power of ten: 1 km = 10³ m, 1 mm = 10⁻³ m, 1 μm = 10⁻⁶ m. Scientific notation writes any number as a × 10ⁿ with 1 ≤ a < 10, so the exponent n shows the order of magnitude at a glance.
A focused learning model
Each trip is a straight line at constant speed, so t = d ÷ v exactly. Speeds are typical values: bacteria swim about 20 μm/s, garden snails about 1 mm/s, fast nerve signals about 120 m/s, and light travels at 299 792 458 m/s, rounded here to 3.00 × 10⁸ m/s. Playback is scaled by a power of ten so every trip can be watched.
SI reference: BIPM · SI Brochure