A Web-based instructional module for teaching middle school students engineering design with simple machines

Journal of Engineering Education, Oct 1998 by McKenna, Ann, Agogino, Alice

In order to be consistent with the hand-drawings, a notebook paper background was chosen along with a pencil for the template. Since some of the modules require the students to sketch their ideas and designs, this interface is also consistent with the cognitive goals and activities. The background, the template, and hand drawings all contribute to a "look and feel" of a learning environment which is intended to be gender equitable.10,11

V. FEATURES OF THE WEB-BASED ENVIRONMENT

The current instructional module consists of many different design features and five of these features, along with the corresponding computer screens, will be described and illustrated in this section. These are:

the Home Page

the Computer Simulation Page for the lever

the Plotting Page for the lever

the Share Findings Page and

the Video Page.

The Home Page is shown in figure 2. This page illustrates the basic look and feel of the environment, all of the subsequent pages have the same background, header, footer, and titles with red text. Such consistency is important, since it orients the user to the web site and connects all of the pages with a single theme.

The computer simulation Java applet for the lever is shown in figure 3. The user has a choice of four loads with different weights: a suitcase, a sofa, a refrigerator, and a car. There is also a choice of three different fulcrum positions. The initial position of the lever is with the load resting on the floor and the opposite end of the lever in the air. The idea is to add weight to the end of the lever until the lever rotates about the fulcrum position and lifts the load. As the fulcrum position changes and moves further away from the load, more weight will be required for the lever to rotate. The students conduct simulations for each weight in the three different fulcrum positions and record their results, thereby demonstrating the principle of mechanical advantage.

The students enter their results from the simulation page on the plotting page. The plotting applet for the lever is shown in figure 4. The resulting graph also illustrates the principle of mechanical advantage for the lever; the further the fulcrum position is from the load, the more weight is needed to lift the load. Both the computer simulation and plotting programs for the lever, figures 3 and 4, were written in Java and are embedded in the web document. They can be run in any Java enabled web browser, independent of the hardware platform.12

The students will also be performing hands-on activities with LEGOSTM. The LEGOTM activity page for the lever provides a list of activities which the students are expected to complete. The hands-on activities serve to familiarize the students with the physical devices and provide an opportunity for them to make connections between the simulation results and the actual "machine." Students are thus provided with multiple representations of the same principle: the physical device, the simulations, and the graphs. The order in which the students engage in the activities is not prescribed. For example, the student can choose to do the LEGOSTM building first, then the simulating, or vice versa. This flexibility exists because students have a variety of different learning styles;l3 some may benefit from performing the concrete examples first, while others may prefer to see the graphs and simulations.