In this video I explain why the light slows down in different materials and how the speed of light never actually changes

See 3Blue1Brown's video here:
   • But why would light "slow down"? | Op...  

Looking Glass Universe Videos:
   • I didn't believe that light slows dow...  
   • I don't know why light slows down in ...  

Harvard video:    • Prof. Lene Hau: Light matters  

Online Simulators I used in this video:
https://javalab.org/en/light_refracti...
https://javalab.org/en/wave_propagati...
https://www.compadre.org/osp/EJSS/403...
https://javalab.org/en/electromagneti...