Questions with the keyword 'glass'

• Why exactly does light slow down when it travels from a vacuum into (say) glass? I assume that gravitational forces by doppler to Adam, Rob, Sheila, SuzieCategory: General Comments: (So far, one comment )
• When light goes through glass, why are photons re-emitted (from the electrons in the substance) in the same direction by doppler to Adam, Geoff, Rob, Sheila, SuzieCategory: General Comments: (so far, 4s comments )