Entry task & exit slip
Introduction to systems of equations, this uses quadratics given 3 coordinate points find the function. Many videos can be used to wet the appetite of students, some of which are listed here:
Basketball arcade game (see the curve generated by the basketball)
Jem melt rock with a parabolic mirror(AWESOME!)
google images of parabolic antennas, mirrors, etc.
The lesson I use is about the St. Louis Arch. The following are a couple of 4 minute videos to get the students excited then the lesson plan and instruction materials are linked as a pdf.
The St. Louis Arch is the Gateway to the west video (4 minutes)
The building of the St. Louis Arch photo collage (4 minutes)
The St. Louis Arch lesson plans
The St. Louis Arch instructional materials