This is a relative motion applet. The applet has a moving river, with a moving boat, and a person walking along the ground. The relative speeds of these can all be changed, and the user can change the frame of reference from which the motion is viewed. The applet displays either one or two dimensional relative motion.
Type of Material:
Java applet interactive simulation.
In-class demo or possibly an assignment.
Identify Major Learning Goals:
Visualize relative motion at constant velocity in one and two dimensions and changes in reference frame.
Target Student Population:
Lower-level undergraduate and high school.
Prerequisite Knowledge or Skills:
Position, speed, velocity and vectors.
Evaluation and Observation
The applet is complete in that it has a number of moving objects, some that move in one dimension and some that can move in two-dimensions. The relative velocities of most of the objects can be controlled. The frame of reference can be chosen to be any one of the objects. There is an option that shows the trajectory of an object which can be viewed with respect to several different reference frames.
The graphics are quite simple, and more realistic images could make the applet more understandable. Simple ovals for boats and small circles for water and trees require a bit of imagination. The wrap around of the moving objects also might be confusing for students.
Potential Effectiveness as a Teaching Tool
This can be a very effective tool to show relative motion because of its flexibility in allowing the user to change reference frames and velocities of more than two relatively moving objects.
The effectiveness may be minimized by the amount of information in the applet and the instructions. A user is going to have to spend some time trying to figure out what is going on, as well as spending time understanding relative motion.
Ease of Use for Both Students and Faculty
The applet allows the user to change reference frames by simply pointing at the frame of reference.
Some of the instructions are a little hard to follow in both the assignment and the applet itself. It took some time and patience to figure it all out.
Not everything that you see in the applet is explained clearly. The narrow rectangle and object moving on it are not explained. There are also statements in the instructions about making the person cross the river that the reviewers could not make happen.
The 2D option gets confusing since the trajectory path can write over itself.
Other Issues and Comments:
Exercises for this applet can be found at http://www.hazelwood.k12.mo.us/~grichert/sciweb/fmlab.htm