How Small Can Something Actually Be?

Travel down a logarithmic ruler from human scale through cells, molecules, atoms and the proton to quarks and the Planck scale. We show how microscopy, scattering and particle collisions test structure, why the 2026 CMS quark result is a model-dependent limit, and why the Planck length is not a proven pixel of space. 0:00 A ruler that changes 0:38 Five powers down 1:19 Inside a cell 2:11 Molecules have many sizes 2:56 The atom is not a marble 3:46 The tiny centre 4:21 How do we see smaller? 5:06 A proton has a radius 5:46 Inside a proton 6:29 Why quarks do not come out 7:13 What counts as elementary? 7:57 Smaller needs more energy 8:41 The 2026 quark test 9:24 The long untested gap 10:07 The Planck scale 10:57 Is there a final pixel?