Topic 3: Velocity-Time Graphs
Standard

1. 8PC1.f. Students know how to interpret graphs of position versus time and graphs of speed versus time for motion in a single direction.

Classroom discussion Show how to take video data and generate separate graphs of x(t), and y(t) using the basketball video.
Investigations There's a good Dynamica activity that does this. Introduce a graph and a vehicle that travels on a one-dimensional track. Kids play around with it and then we show them a graph and try to get them to match it by moving the vehicle. Or we hide the vehicle (it goes into a "foggy" patch and disappears) but show the graph and ask the kid to point to where he thinks the vehicle is. Or we allow them to control the vehicle by manipulating the graph and accomplish something (e.g., arriving at the train station on time, or matching the velocity of some other vehicle. Or two trains running on parallel tracks and our hero has to jump from one to another - where should he jump? Indicate where on the graph and then run the simulation to see.)

Featured software

• Ultrasonic motion detector with the CCgrapher. This time, the student sees both a position and velocity graph. They investigate sketching one from the other.
• Moving Man from PhET http://phet.colorado.edu/simulations/sims.php?sim=The_Moving_Man

Extensions. Program an object (by dragging "boosters" or "forces" onto a timeline) to get it to make a graph that looks like one that is presented.
Suggested lab Motion detector with graphs. "Choreograph" your walk so as to make a graph that looks like this.
Assessments. When they run the activities, check to see what mistakes they make and whether they can figure out their mistakes and correct them. How many trials do they make before they get it right? Do they make the right kind of corrections between trials?

Again, let's remember to include the very small and very large.