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tangible table with planet

Gravitation - Tangible table

Is there a way to explain natural phenomena to people in a non complicated and fun way?

We were asked to build an interactive installation for a science museum to educate young and old about phenomena in nature either on molecular, planetary, interplanetary or interstellar level.

Date: 2018
Type of project: Student project
Project time: 6 weeks
Team members: Bambi Boland

global concepts

Interplanetary phenomen gravitation

With a former group of 6 people, we brainstormed about the different natural phenomena. We choose interplanetary to scope the broad topic. After researching about different interplanetary phenomena, we came up with global concepts, split up in smaller groups to work in pairs on our favorite concept. Bambi Boland and I teamed up and decided to explain gravity with the help of a tangible table and movable planets, to explain in a visual and simple way how the impact of gravity works on the planets and their surroundings.
At first we had to research about how you can actually build a tangible table. With the program “reactivision”, a camera is able to recognise fiducial markers. These are placed mostly under the physical objects, as the beamer and the camera are placed under the table for a clean output.

fiducial marker test
research about tangible table

Reactivision and fiducial markers

Processing (language Java) was used for the visuals. What looks like splines, are in reality lots of small lines. Behind the visible grid is a second static and not visible one, which works as a reference for the points of each line. To show the impact of each planet, the physical law of gravitation was implemented into the code. F (stretch of grid) = m (mass of each planet) * a (acceleration of each planet). Thanks to Markus, for helping us out.
As the beamer light would interfere with the camera in the darkness, a night camera had to be used. Because of our low budget we converted a cheap webcam into a night cam, by removing the infrared light filter and adding a layer of photo development paper. With a small line of infrared LEDs the camera was tested. The former web camera could see now infrared light and therefore, see in the night.

testing night cam
building tangible table

Sometimes things work out differently.

To see only the projection on the glass and not what lays under it, baking paper was sticked to the glass table to simulate milky glass. Infrared light was shined under the glass table to make only the fiducial markers visible for the night camera. The projection light by the beamer would only be visible to the human‘s eye.
In the end the program Reactivision had problems with detecting the fiducial markers in the darkness, as the quality of the webcam was not high enough. It is highly recommended to use a real night camera to avoid this problem. Nevertheless a video was made, in which the working tangible table was simulated. It was actually a fun experience, as Bambi hold the fiducial markers in front of the webcam and I tried at the same time to follow with the planets the visuals on the table.

tangible table with planet

We learn not by only seeing, but also touching. Together, it enhances our experience and learning process.

The project’s goal was it to explain the phenomena “gravitation” in a simple, fun and interactive way for a science museum. Depending on mass and size of the object, its impact on its surroundings are greater or smaller, which can be visualised in a gravitation grid. As we wanted to make the experience engaging and exciting for young and old, we decided to build a tangible table, which is a digital interface controlled with physical objects. The digital interface consists of the gravitation grid on which you can move planets around to see and learn about their impact on gravity, depending on mass and size. This project is an interesting example, how digital interfaces can work together with physical objects to improve the experience for the user. Especially for increasing the learning process, it is essential to acknowledge, that we learn not only by seeing, but also by touching.

planet jupiter
planet saturn
planet earth
planet neptune