Why is energy conserved? What's a gauge symmetry? How were quarks discovered? All these answers in 15 minutes! 0:00 - Introduction 0:35 - Global symmetries 2:23 - Conservation laws 4:17 - Global symmetry for electrons 5:49 - Our real universe 7:42 - Changing point of view 11:23 - Local symmetry for electrons 13:10 - Conclusion For more videos, subscribe to the YouTube channel : https://www.youtube.com/ScienceClicEN And if you liked this video, you can share it on social networks! To support me on Patreon : http://www.patreon.com/ScienceClic or on Tipeee : http://tipeee.com/ScienceClic Facebook Page : http://facebook.com/ScienceClic Twitter : http://twitter.com/ScienceClic Instagram : http://instagram.com/ScienceClic Alessandro Roussel, For more info: http://www.alessandroroussel.com/en _ To learn more : https://en.wikipedia.org/wiki/Symmetry_(physics) https://en.wikipedia.org/wiki/Gauge_theory