Vertical Angles

Yesterday and Today I substituted for a sixth grade class at the middle school. I have such a great time with these kids. The teacher I subbed for teaches one period of World Civ, two periods of General Math and two periods of science. My favorites! I especially love teaching math. I get jazzed about presenting a concept then giving the assingment and then working with individual students. It is during that individual instruction that I see the "light" go on and the independence of thought take shape.

Yesterday I presented a lesson on angles: acute, obtuse, right, straight, vertical, supplementary and complimentary. I was magnificant (or so I thought). In one of the classes I taught there is an aid who is assingned to assist because the class is so large. As I was walking around helping individual students I over heard her describe vertical as a line opposite from horizontal. I was confused as to why she would use that analogy with vertical angles. I stopped her and breifly described vertical angles to her as the angles opposite eachother when two lines intercect, each has the same measure. She looked at me blankly, I moved on. Well, today I was correcting the assingment from yesterday and I'll be danged if every student she stopped to help labled the two intercecting lines instead of the angles. I was so discouraged. I'm sure that the teacher will look at those papers and say, "stupid sub." The thing is there were SO many students who made this mistake that I can't be sure that I didn't explain the concept well enough or if it's easier to locate a line than it is to locate angles or if the aid was talking lines and not angles.
Who knows? But, I left discouraged and with a headache.