Providing Real-time Automatic Feedback to Students:
One important design principle we incorporate into as many Gizmos as possible is to provide real-time feedback to students as they work through the interactive.
An example of this is evident in the Cladograms Gizmo. Cladograms are diagrams that describe the relationship between organisms. It can be difficult for students to draw cladograms without guidance, but it becomes easy once it is broken down into smaller chunks. I designed the Cladograms Gizmo to guide students through this process.
I broke down the cladogram building process into several steps: 1) identifying the characteristics in each organism by filling in a table, 2) re-organizing the table to better classify the collected data, 3) drawing the cladogram diagram based on the organized data table. Each of these steps are done on different screens of the Gizmo.
It was important that students received real-time feedback on their work as the progressed through the Gizmo so they knew they were on the right track. For example, after the user filled in the table with their responses they could click on the “Check table” button to check their work before moving on.
One of the design challenges in this Gizmo was making sure students were able to see all the relevant information they needed to see on screen at the same time given the relatively small sized screens Gizmos encompass.
To make sure this was possible, I split the left side of the screen into two tabs. On the Organisms tab on the left of the Gizmo, there are images and information about the organisms that allow the user to fill out the table on the right side of the Gizmo.
On the cladogram tab, that can be toggled to on the left side of the Gizmo, there is a widget that helps the user draw a cladogram diagram based on the table. Once the user fills out the table, they do not need to see the organism images anymore, so that space can be used for the cladogram diagram.
I gave the students another opportunity for real-time feedback on the cladogram tab. When the user draws a cladogram by clicking on the empty dotted lines on the diagram, they will know that they have draw a valid cladogram diagram when the purple lines, that represent characteristic changes, appear. They can also select the “Cladogram help” check box to give them hints about how to complete their cladogram.
Breaking down the cladogram building process into smaller chunks coupled with real-time feedback helps students more easily understand the cladogram building process and empowers them to follow the same process on their own.
Using simulation data to strengthen understanding:
One of the other important Gizmo design principles is to use simulation data to allow students to experiment on their own.
In the Muscles and Bones Gizmo, students build an arm model and determine how much weight the arm can lift. There are different parameters to experiment with, such as muscle type (with different ratios of slow- and fast- twitch muscle), position of tendon attachment, and forearm length. Students determine how these different parameters affect the mass the arm can lift.
I wrote a detailed math model for this Gizmo based on the physics of a third-class lever. The elbow is the fulcrum, the forearm is the lever, the muscle is the effort and the dumbbell is the load. There are a few additional variables built into the model to account for other variables like the presence of cartilage. When students change the variables, they are given accurate feedback, and can even too the physics calculations on their own if they want to confirm their observations.
Simulations with accurate data allow students to experiment on their own. They can hypothesize about how a changing variable will affect the outcome. They can set up experiments to test their hypotheses, collect and analyze data to form their own conclusions. By being an active participant in this process, students gain a better understanding of arm mechanics.