To show and then play a video clip, click on the arrow or the video clip title/description. Repeat to hide it. Note: Most of this lesson was part of USE L2 during the semester when these video clips were made.
USE L4 Video Clip 1: Group discusses acrylic touching base of soda can
The group discusses what they think is happening to the negative charges when the + charged acrylic touches the base of the soda can, that causes the tinsel to spread out. They discuss whether the can is + charged or – charged and decide it must be the same as the tinsel (+ charged); otherwise the tinsel would be attracted towards it. [Note: The drawings in their materials are slightly different from the ones on page SE-28 in the current version of the materials.]
USE L4 Video Clip 5: Class discusses why touching the can discharged tinsel & touching the bottle didn't
One student explains that electrons traveled from our finger through the can to the tinsel to discharge the can (and the tinsel went down). With the water bottle the electrons cannot travel through it. A second student explained that the electrons went the other way from the tinsel through the can to our finger causing the can to be discharged. The instructor asked which of these ideas are better supported by the evidence and a third student argued that since the tinsel was + charged to begin with then to discharge it the electrons had to go from finger to tinsel. The second student then realized she had been wrongly assuming the tinsel was – charged.
USE L4 Video Clip 1: Group discusses acrylic touching base of soda can