For many teachers, instruction using web pages conjures up the image of a book in the vertical plane and no pedagogical advantage. With the advent of Java applets this is no longer the case. This paper aims to demonstrate that applets are very powerful as a medium of instruction. Examples of several ways in which applets can improve mathematics instruction will be given. The reader, however, should not be left with the impression that these applets are all that can be done. The hope is that the reader will think of instances where an applet would be appropriate in his or her teaching. The level of the material to be learned can be anywhere from elementary school to tertiary level.
We start with applets used to generate examples and instances of the objects under discussion. The applet below is inserted in a web page just after acute and obtuse angles have been defined. Rather than one or two pictures of acute and obtuse angles the terminal side sweeps through angles from 0 to 180 degrees.
You will find that even people who are quite familiar with acute and obtuse angles will patiently watch the applet as the angles change. What this applet is doing is holding the students attention and reinforcing the definition. Many students watch carefully to see if at 90 degrees it does say right angle. It is desirable to have a start/stop button so that students can stop the animation when they are done with it. This way the applet does not become a distraction.
Here is another applet that provides examples, this time of triangles. We can also use this applet to practise estimations -- try to stop the applet when one of the angles is 45 degrees without watching the figures, for instance. Also, since the angles measures are provided many students will, on their own initiative, check to see that they do add up to 180 degrees.