|Above picture from|
free online graph paper
Wednesday is our first day of class. New students arrived here on Sunday, so we're in the midst of two days of orientation and partying.* I've spent the past week making final preparations for teaching 9th grade conceptual physics -- no wonder I haven't posted much.
*Unfortunately, the skee-ball machine is delayed, so probably won't be at my house for my advisee group's get-together tonight. I'll have to use it for physics classes, instead.
In the first class session, we will set up a mirror and ray box. Students will take turns using a protractor to measure angles of incidence and reflection. Each student will make a graph of angle of incidence on the horizontal, and angle of reflection on the vertical. The point here is to establish context for reflection and refraction, and to be sure we all know how to use a protractor before the first true laboratory exercise on refraction.
In a 12th grade course, I'd have students figure out how to scale the graph. Dealing with a range of 0-90 degrees, when the graph paper has seven major ticks and 70 minor ticks on the horizontal axis, is a serious skill that I try to teach, and which takes significant patience and practice. However, for 9th graders I'm happy if they can plot points accurately at all.
So I've gone to this link for free online graph paper. This page is particularly nice because you can choose from common templates (e.g. 1 inch major with 1/10 inch minor gridlines), OR you can customize the weight of the line, number of lines per inch, etc.
For that first class session, I can bring the class to understand that we need to scale each axis from 0-90 degrees. Making that scale will be easy as pi, because I've printed out customized paper that has nine major gridlines across the page, and five minor gridlines per major gridline. The class can see quickly that each major line will represent 10 degrees, so each minor line will represent two degrees. And the graph will take up the whole page.