Why are tv's interlaced? I mean it just seems like having progressive scan would be easier, but I could be wrong. Could someone please explain where interlace came from and why it is still in use today.

Howdy from Texas,

The short answer is that interlace reduces flicker.

I went to Google and plugged in: NTSC history television interlace

Here are some interesting hits which will answer your question in much greater detail:

http://www.udayton.edu/~cps/cps460/notes/displays/video_standards.html

http://www.ieee.org/organizations/history_center/milestones_photos/colortv.html

http://www.tvhandbook.com/History/History_TV.htm

-- hope this helps,