sparks to wire held by instructor (student) Causes fluorescent tube, neon gas to glow Lines seen in grating show effect of quantum mechanics (to come later) Lecture 2: Motion Electric tractor on a large 
(neon gas; to glow; Lines seen in grating show effect of quantum mechanics (to come later) Lecture 2:)
neon gas
to glow
Lines seen in grating show effect of quantum mechanics (to come later) Lecture 2: