Vectors.

Sometimes teaching high school is challenging.


This is not to say teaching elementary or (dear god) junior high is not challenging, but high school students present a whole different challenge in the professionalism department.

Usually for me, this is in the form of mildly inappropriate jokes, the kind that you usually keep in your head, but sometimes slip out in the "did I say that out loud?" kind of way. The "that's what she said" type of joke. Often times my students will make double entendre comments, and I just have to giggle under my breath.

In physics right now, we are learning how to add vectors using vector diagrams. Simply put, a vector is an arrow that represents a quantity, where the length of the arrow shows the size, and the direction is indicated by orientation. All vectors must have an arrowhead (at the tip) to show which way they are pointing.

If you were to say, walk a certain distance east, and then walk a certain distance north, we could show that using vectors. To make sure our diagram works out properly, vectors are always drawn so that the end of the first vector is where you start to draw your second vector. This is known as the "tip-to-tail" method of vector addition.

To determine how far away from your starting point you are, if you were to walk the above path, we would draw a new vector from the original starting point to the final end point, like such.

Measuring the length and direction of the red vector would give you your final displacement. Of course, I am not the most accurate drawer, and unless you are using a scale diagram, the actual length of your vectors is not important; most of the time we solve these problems using trig and the diagram is just to help.

So I draw a pretty sloppy resulting vector on the board, and one boy puts up his hand to ask,

"Are those two tips supposed to be touching?"

Hysterical giggles all around. One kid snorts while original boy is protesting how serious the question is. Snigger.

This is the start of a new unit. Better get the giggles out of your systems, boys. There are going to be lots of tips touching over the next few weeks.

Hoo boy.