Posts Tagged ‘Frame’

Some thoughts and variations of the Gas Frame (a natural user interface for learning gas laws)

August 14th, 2013 by Charles Xie
A natural user interface (NUI) is the user interface that is based on natural elements or natural actions. Interacting with computer software through a NUI simulates everyday experiences (such as swiping a finger across a touch screen to move a photo in display or just "asking" a computer to do something through voice commands). Because of this resemblance, a NUI is intuitive to use and requires little or no time to learn. NUIs such as touch screen and speech recognition have become commonplace on new computers.

As the sensing capability of computers becomes more powerful and versatile, new types of NUI emerge. The last three years have witnessed the birth and growth of sophisticated 3D motion sensors such as Microsoft Kinect and Leap Motion. These infrared-based sensors are capable of detecting the user's body language within a physical space near a computer with varied degrees of resolution. The rest is how to use the data to create meaningful interactions between the user and a certain piece of computer software.

Think about how STEM education can benefit from this wave of technological innovations. Being scientists, we are especially interested in how these capabilities can be leveraged to improve learning experiences in science education. Thirty years of development, mostly funded by federal agencies such as the National Science Foundation, have produced a wealth of virtual laboratories (aka computational models or simulations) that are currently being used by millions of students. These virtual labs, however, are often criticized for not being physically relevant and not providing hands-on experiences commonly viewed as necessary in practicing science. We now have an opportunity to partially remedy these problems by connecting virtual labs to physical realities through NUIs.

What would a future NUI for a science simulation look like? For example, if you teach physical sciences, you may have seen many versions of gas simulations that allow students to interact with them through some kind of graphical user interface (GUI). What would a NUI for interacting with a gas simulation look like? How would that transform learning? Our Gas Frame provides an example of implementation that may give you something concrete to think about.

Figure 1: The Gas Frame (the default configuration).
In the default implementation (Figure 1), the Gas Frame uses three different kinds of "props" as the natural elements to control three independent variables related to a gas: A warm or cold object to heat or cool the gas, a spring to exert force on a piston that contains the gas, and a syringe to add or remove gas molecules. The reason that I call these objects "props" is because, like in film making, they mostly serve as close simulations to the real things without necessarily performing the real functions (you don't want a prop gun to shoot real bullets, do you?).

The motions of the gas molecules are simulated using a molecular dynamics method and visualized on the computer screen. The volume of the gas is calculated in real time using the molecular dynamics method based on the three physical inputs. In addition to the physical controls through the three props, a set of virtual controls are available on the screen for students to interact with the simulation such as viewing the trajectory path or the kinetic energy of a molecule. These virtual controls support interactions that are impossible in reality (no, we cannot see the trajectory of a single molecule in the air).

The three props can control the gas simulation because a temperature sensor, a force sensor, and a gas pressure sensor are used to detect student interactions with them, respectively. The data from the sensors are then translated into inputs to the gas simulation, creating a virtual response to a real action (e.g., molecules are added or subtracted when the student pushes or pulls a syringe) and a molecular interpretation of the action (e.g., molecules run faster or slower when temperature increases or decreases).

Like in almost all NUIs, the sensors and the data they collect are hidden from students, meaning that students do not need to know that there are sensors involved in their interactions with the gas simulation and they do not need to see the raw data. This is unlike many other activities in which sensors play a central role in inquiry and must be explicitly explained to students (and the data they collected must be visually presented to students, too). There are definitely advantages of using sensors as inquiry tools to teach students how to collect and analyze data. Sometimes we even go extra miles to ask students to use a computer model to make sense of the data (like the simulation fitting idea I blogged before). But that is not the reason why the National Science Foundation funded innovators like us to do.

The NUIs for science simulations that we have developed in our NSF project all use sensors that have been widely used in schools, such as those from Vernier Software and Technology. This makes it possible for teachers to reuse existing sensors to run these NUI apps. This decision to build our NUI technology on existing probeware is essential for our NUI apps to run in a large number of classrooms in the future.

Figure 2: Variation I.
Considering that not all schools have all the types of sensors needed to run the basic version of the Gas Frame app, we have also developed a number of variations that use only one type of sensor in each app.

Figure 2 shows a variation that uses two temperature sensors, each connected to the temperature of the virtual gas in a compartment. The two compartments are separated by a movable piston in the middle. Increasing or decreasing the temperature of the gas in the left or right compartment through heating or cooling the thermal contacts in which the sensors are applied will cause the virtual piston to move accordingly, allowing students to explore the relationships among pressure, temperature, and volume through two thermal interactions in the real world.

Figure 3: Variation II.
Figure 3 shows another variation that uses two gas pressure sensors, each connected to the number of molecules of the virtual gas in a compartment through an attached syringe. Like in Variation I, the two compartment are separated by a movable piston in the middle. Pushing or pulling the real syringes will cause molecules to be added or removed from the virtual compartments, allowing students to explore the relationships among number of molecules, pressure, and volume through two tactile interactions.

If you don't have that many sensors, don't worry -- both variations will still work if only one sensor is available.

I hear you asking: All these sounds fun, but so what? Will students learn more from these? If not, why bother to go through these extra troubles, compared with using an existing GUI version that needs nothing but a computer? I have to confess that I cannot answer this question at this moment. But in the next blog post, I will try to explain our plan for figuring this out.