The following design guidelines for dynamic worksheets on the next few worksheets are the result of a formative evaluation of dynamic worksheets created by teachers in our NSF MSP classes during fall 2006 and spring 2007. The guidelines are based on design principles for multimedia learning stated by Clark and Mayer[sup]1[/sup].[br][br]These guidelines were summarized to address and avoid common mistakes during the creation process of dynamic worksheets as well as to increase their quality with the hope that they will foster more effective learning. Although some of these guidelines may seem obvious, we have found it very important in our work with teachers to discuss and explain them in detail.[br][br]The following figure shows a dynamic worksheet created with GeoGebra that allows students to explore properties of the orthocenter of a triangle. By modifying the dynamic construction students can examine the orthocenter of a great variety of triangles instead of just one special case. Several key words within the explanation and tasks match the color of the corresponding objects in order to facilitate finding them within the construction. Furthermore, the tasks are placed next to the dynamic construction in order to fit all information on one screen and avoid additional cognitive load through scrolling.[br][br]

Below you can see a triangle ABC together with its heights. [br]The intersection point of the three heights is called [color=#ff0000]orthocenter[/color] of the triangle.[br]

[size=100][sup]1 [/sup]Clark, R. and Mayer, R.E. (2002): e-Learning and the Science of Instruction. San Francisco: Pfeiffer, 2002[/size]