For my final project for the courses I took at NYU's Interactive Telecommunications Program, I created a table top "slide" intended as a science museum hands on exhibit. Similar in concept to the playground slide I've helped to develop at the New York Hall of Science, this table top version is designed to support an entirely different user experience. While the giant playground slide is part of a game students play to get to specific science content, the table-top version is designed to support a more open ended interaction. It is essentially a tool for students to engage in scientific inquiry. Students should be able to use this as a device to answer their own questions about energy and friction, carrying out whatever experiments they desire, rather than following a predefined path set by the designer.
The slide consists of an inclined plane and a bowl. Embedded in the wooden rails of the inclined plane are laser diodes and photogates used to detect the presence of an object. Underneath the bowl is a sensor that measures mass. When an object trips both beams and falls into the bowl, the microcontroller notes the time difference and weight of the object and sends this information to a computer running a program I wrote on Max/MSP that renders an animation of an object going down the slide as well as a piechart animated to display the different types of energy it has at each stage of its' descent. By looking at the way the object's energy is transformed from 100% potential energy in the beginning to some combination of kinetic energy and energy lost to friction, students can get a strong qualitative (numerical values for speed and energy are deliberately not displayed) sense of energy transfer and conservation. It may just be that I am a physics nerd at the core, but I think its interesting that so much can be known about velocity, kinetic energy, potential energy, and energy lost to friction from two values, the time difference and mass (provided the computer already knows the distance between the lasers, the original height of the slide and acceleration due to gravity, of course).
The overall design of the project was created to streamline the user interaction and make it as intuitive as possible. I wanted to give the user the ability to take an object (one of their own or one of an assortment of objects I included for them to use), place it at the top of the slide, let it go and see what happens. I feel that the instant the user is asked to follow a procedure, no matter how simple the procedure is, it detracts from the playful experience and adds a little difficulty of use in an environment where the average engagement time of an interaction is measured in seconds if not minutes. This is why I stayed away from having the user register the mass of the object then place it on the slide like the playground slide game we developed at SciPlay (although there are other reasons for that exhibit being the way it is). I played around with having preset objects for use in the exhibit so that the microcontroller would already know the mass without having to weight it, but this prevents the user from pulling something out of their pocket to try.
The exhibit is a work in progress that needs a lot of tweaking before it is ready. I hope to present it to my the museum's administration in a few months to get it on the museum floor and in the hands of kids and other museum goers. Namely, the photogates need to be optimized to capture faster objects, and the pressure sensitive resistor used to measure mass needs to be replaced with an actual load cell. With that in mind, here is a video that shows its' basic use.
