Get 2 months of Skillshare Premium for free at: https://skl.sh/stevemould4 Metals have a crystal structure. But they're not one big crystal, they're lots of small crystals called grains. The size of the grains affects the physical properties of the metal, like hardness, toughness, strength, mailability, ductility, plasticity. Heating a metal can change the size of the grains. This ball bearing model demonstrates annealing. Ductility is dependent on how far dislocations are able to travel in the metal which is dictated by grain size. Original ball bearings video here: https://www.youtube.com/watch?v=O3RsDIWB7s0 Other metal heat treatment videos here: https://www.youtube.com/watch?v=6jQ4y0LK1kY https://www.youtube.com/watch?v=uG35D_euM-0 You can buy my books here: https://stevemould.com/books You can support me on Patreon here: https://www.patreon.com/stevemould just like these amazing people: Glenn Watson Joël van der Loo Matthew Cocke Mark Brouwer Deneb Image credits: First microscope grain image (1:11): Tugsataydin https://commons.wikimedia.org/wiki/File:Paslanmaz_çeliğin_mikroyapısı.jpg Second microscope grain image (1:19): Edward Pleshakov https://commons.wikimedia.org/wiki/File:CrystalGrain.jpg Dislocation diagrams (4:14, 4:18): Cdang https://commons.wikimedia.org/wiki/File:Dislocation_coin_vue_en_bout_et_coeur.svg Twitter: http://twitter.com/moulds Instagram: https://www.instagram.com/stevemouldscience/ Facebook: https://www.facebook.com/stevemouldscience/ Buy nerdy maths things: http://mathsgear.co.uk/