physics
https://www.youtube.com/playlist?list=PLMguVyWLTFUkQrAc9JojjXKn4Hg2L_AVK
https://www.youtube.com/playlist?list=PLB03A41EA88A8DE65
chemistry
https://www.youtube.com/playlist?list=PLMlqayk59Ivp3Ul_4fA_l1A6Xtkbcwbei
biology
https://www.youtube.com/playlist?list=PLMguVyWLTFUmEKYQ8tI_jVDp_Lhp7Xltu