Charges and Fields — An electrostatic virtual lab

ElectroHaptics: A virtual lab for experiencing charges and fields

Team name: Eduhap

Names: Soheil Kianzad, Matthew Chun, Lotus Hanzi Zhang

Contact: skianzad@cs.ubc.ca, mchun345@cs.ubc.ca, zhzcs@ubc.cs.ca

Learning Description

Learning Goals

Our goal with ElectroHaptics is to teach people the principles of electrostatics in an exploratory and tangible way. To do this, we enable individuals to feel abstract electric strength forces based on various configurations of electric charge particles.

We chose electrostatics as our challenge topic due to its importance in everyday applications such as capacitors and batteries. Electrostatics was also chosen due to its underlying principles being related to concepts such as gravity and DNA structures [1].

Thus, another related learning goal would be to teach how principles such as inverse-square relationships can be generalized to analogous concepts.

Learning Environment

Using ElectroHaptics, people create electric charge particles that can be varied in their properties such as their coulomb levels ( C ) and polarity (+ or -). The particles can also be freely positioned in order to investigate how these properties affect the direction of electric fields, which are represented as moving lines.

Moving lines were chosen to represent electric fields due to the interactive nature of ElectroHaptics. Compared to static electric field diagrams, moving lines are able to dynamically change direction based on the user defined positions of placed electric charge particles.

When compared with traditional static figures of particles and their fields, we believe that the flexibility of ElectroHaptics in creating various types of charge particles and seeing the resulting simulated electric field directions will better reinforce the analysis of the connection between fields and charges.

Our haptic effect to represent electric force strength is designed to resemble the “tension” an individual might feel when bringing magnets close together. Using Haply to move a selected charge particle, the intensity of this effect is based directly on the distance of a selected electric charge particle to the closest particle. Smaller/closer distances will result in more dramatic strength changes versus that of larger/further distances — reflecting the nature of the inverse-square relationship as denoted by Coulomb’s Law [2]. For additional visual reinforcement, a force vector is also shown to show the strength and direction of a selected particle’s electric force. A sound effect was also incorporated, where the volume of the sound would be proportional to the inverse-square relationship.

Inverse-square law in action for Coulomb’s Law. As distance R changes, the resulting force F changes from dramatic to less dramatic.

By using familiar physical metaphors in addition to corresponding multi-modal cues, we believe this will help understand the nuances of the inverse-square relationships at play, which is normally unintuitive to understand. Put simply, we want people to be able to “feel” the graph relationships driving electrostatics.

To further solidify these concepts, we propose a video game that utilizes and tests these concept’s as game mechanics used to complete challenges. It is the hope that the games can help “click” the abstract ideas taught using our virtual lab environment in a more engaging way.

Electric Field Sailor — Sail to the destination through optimal positioning of electric charge particles

In this game, the goal is to help sail an avatar towards a destination area on a map. Movement of the avatar is done through the movement direction of electric fields, that can be altered through the creation and placement of electric charge particles.

The players have no direct avatar movement control — they must rely on the “current” direction provided by the electric fields to complete each level of the game.

Levels would become more challenging by providing fixed electric static charges of specific Coulomb levels that would further adjust the flow of the electric field movements.

Essentially, this game utilizes the analysis of electric charge particles on electric field directions in order to solve each level of the game.

A video demonstrating the gameplay in action can be seen below.

https://www.youtube.com/watch?v=BeiwrVbC81A&t=2s

System Description

ElectroHaptics allows learners of electrostatics to create various configurations of different types of electric charge particles and to observe the resulting effects on electric fields and force strength in real-time.

To achieve this, we modified an existing Processing electric field pattern generation sketch [3] to create the visualizations of the real physics of electric fields based on different types of electric charge particles.

For the haptics, we used Haply as the main tool using the provided hAPI and sending it the necessary physics generation information to tangibly create the “tension” effect described.

Operation of our system is quite simple. An electric charge particle of either + (red) or -(blue) polarity can be made by first clicking on the desired particle in the toolbar located on the bottom of the interface. Then clicking anywhere else on the main screen will create the charge. The Haply can then be used to control the most recently dropped charge via the movements through the handle.

Hardware Details

We used Haply as the main form of user input for moving charge particles, and for feeling any consequent haptic effects based on different particle configurations.

It was the “analog” nature of being able to move the selected electric charge particle using the Haply that cemented it as the hardware of choice.

For example, the Haply can be used to “push” or “pull” in or around a particular charge particle. A person can even do this action in a myriad of ways, such as doing it quick or slowly, to really feel the differences in resulting force strength that we think would encourage exploration of various particle configurations.

Software Details

As mentioned previously, the main software used was Processing, Arduino, and the conference provided libraries (hAPI, etc) needed to get Haply running.

We used the following Processing sketch [3] as an initial starting point to generate the visualizations of electric fields.

Beyond that we made no real changes to the provided software itself.

Our source code is available at: https://github.com/ryanbom/Electrostatic-virtual-lab

Reflection

Overall, this challenge was an interesting experience from a design perspective for novice haptic designers.

Most notably, unlike typical design challenges often done using purely software, the need to constantly work with a tangible physical device like the Haply was both cool and challenging to work with.

The cool factor came from the fact that the software being written had a real life consequence that could be felt and adjusted based on “feel”. The challenge was that the Haply had to be on hand to do any real meaningful development work. Thus, it was challenging to delegate tasks since most of it required specific individual expertise (eg. engineering, physics) in tandem with the Haply itself.

By only having access to a single Haply device, it necessitated face to face working time that was occasionally difficult to schedule, unlike the usual asynchronous software development work style we’re all used towards.

Of course, time was an issue, which prevented additional planned features from being implemented.

Hardware issues such as “limit cycles” (intense vibrations of the Haply) also arose, especially in cases where an opposite charge particle was immediately placed next to another particle. Unfortunately, there was no time to fully investigate and fix this bug.

For example, we were planning to implement a real-time force strength-distance graph much like [2] that would have corresponded to a selected charge particle’s force strength in relation to nearby particles. This may have helped reinforce the “graph” understanding of inverse-square law that is taught to Canadian (British Columbian) high school students before any scientific concepts are formally taught [4].

Additionally, we had ideas for other types of video games to test an individual’s knowledge, and notably we could not implement the game proposed due to lack of time and game logic required.

Finally, it would have been great to informally test out our prototype among individuals with little to no knowledge of electrostatics. We also lacked time to implement another aspect of electrostatics, that of electric potential energy, which was unfortunate.

We were especially keen on the domain of cognitive learning — the idea that students could transfer knowledge of one concept onto other related ones. In our case, it would have been interesting to see if understanding of inverse-square relationships could also been applied to gravity. This could have been achieved with “switchable” visualizations.

References

[1] Applications of Electrostatics

https://www.boundless.com/physics/textbooks/boundless-physics-textbook/electric-charge-and-field-17/applications-of-electrostatics-138/

[2]Inverse-square relationship of Coulomb’s Law

http://web.ncf.ca/ch865/englishdescr/Coulomb.html

[3] Electric Field Processing Sketch

https://forum.processing.org/two/discussion/5729/electric-field-pattern-generated-by-two-charges

[4]Canadian British Columbian Physics Curriculum

http://www2.gov.bc.ca/assets/gov/education/kindergarten-to-grade-12/teach/pdfs/curriculum/sciences/2006physics1112.pdf

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