Scale of U

Scale of U draws everything at its true relative size, from a proton to the observable universe. Pinch to zoom and travel across 42 powers of ten: atoms and molecules, insects, people and animals, everyday objects, moons and planets, stars and galaxies.

What you can do
• Explore 161 objects in 3D, from the proton and the hydrogen atom to the Milky Way and the observable universe
• Zoom smoothly from 10⁻¹⁵ to 10²⁷ meters with a pinch, the slider, the scale buttons or a keyboard
• Tap any object to center it, turn it in 3D and read what its size measures
• Compare two objects side by side at one shared scale, such as Earth and the Moon or a honeybee and a grain of sand
• Walk through ten categories in size order: everyday objects, the solar system, worlds, moons, exoplanets, stars, galaxies, insects, molecules and elements
• Take a guided tour from tiny to vast, at your own pace
• See NASA surface maps and Hubble photographs, each with its credit

Made for classrooms and curious people
• Free, with no ads, no accounts and no data collection
• Designed for iPad and iPhone, in landscape or portrait, and in Split View
• 3D models download as you explore and in the background on Wi-Fi, so the app works offline once they are stored. Until then, every object shows a picture.

Honest about sizes
Every object says what its number measures: a diameter, a length, a wingspan or an orbit. Sources are listed for each one. Models are schematic where no photograph exists.

Scale of U is also on the web at scaleofu.com. Made by Grossard Education.