Paper: Second Life a good fit for alternative physics simulations

Second Life is a “viable and flexible” platform for physics simulations testing alternatives and predecessors to Newtonian physics, according to a paper published last month by a professor at the Lutheran University of Brazil

The choice to use Second Life for the experiment was a simple one.

“As I researched a few virtual worlds, I discovered that Second Life was the one with the most complete set of physics scripting functions,” Professor Renato dos Santos, the author of the paper, told Hypergrid Business.

Experimental Set-Up

Dos Santos used a simulation of a cannonball being fired from a cannon. The cannon was designed to simulate both Newtonian mechanics and Buridan’s Impetus Theory, which is a secondary theory of Aristotelian dynamics and the predecessor to Newtonian mechanics.

Professor Renato dos Santos
Renato dos Santos

When creating the simulation, dos Santos faced various hardships related to the nature of Second Life’s physics engine. Not only are there no fluids in Second Life, and so no air resistance, but Second Life has different meanings for physical quantities such as mass, acceleration, and energy.

“Physical objects are, in principle, affected by Second Life ‘wind’ and ‘gravity’ and, therefore, they will not keep that velocity constant and will deviate from its rectilinear trajectory,” said dos Santos.

Although the cannon, when fired from the cannonball, felt the effects of the Second Life wind and gravity, dos Santos was able to write scripts so that the cannonball followed a different set of rules, allowing him to explore the effects of Buridan’s Impetus Theory as compared to Newtonian Mechanics.

The alternative physics cannon experiment in Second Life. (Image courtesy dos Santos.)
The alternative physics cannon experiment in Second Life. (Image courtesy Renato dos Santos.)

Difficulties in Creating the Simulation

Dos Santos found that despite the difficulties involved in creating a simulation, the 3D world provided a much more enriching environment than a regular, 2D simulation would.

One such difficulty was that Second Life can only return the position and velocity of an object, not the kinetic energy or momentum. However, this is easily overcome by calculating the desired values, although the slight differences in Second Life physics versus real physics means that extra attention must be paid to the assumptions made when going through the calculations.

Another difficulty was ease of use for the students.

“Most users agree that a high learning curve exists for new users,” dos Santos said in the paper, “which means that any proposal of using of Second Life for teaching has to set aside several hours, just to have the students become familiar with basic tasks such as walking, passing through doorways, going up stairs, manipulating objects, and so forth.”

However, these difficulties were made up for by the variety of options offered by the scripting language of Second Life. Dos Santos was able to set the initial position and velocity of an object by using the Linden Scripting Language’s llRezObject function. He was able to set the mass using the llSetScale function, as Second Life determines the mass of an object based on size, and not on physical material.

“Despite the restrictions and differences between Second Life and a ‘traditional’ simulator, Second Life shows itself as a viable and flexible platform for microworlds and simulations,” dos Santos said.

Dos Santos’ results provide a strong argument for the use of virtual worlds in physics education. Although applications of this are limited, as the Second Life physics engine only accounts for mechanics, not electromagnetic or nuclear reactions, these problems can be overcome by a knowledge of the Linden Scripting Language.

Other problems, such as the inaccurate portrayal of light, would be harder to overcome. In Second Life, light has no physical mechanism involved in its creation or propagation. Light is just there. This means that any sort of modern physics experiment beyond introductory mechanics and electricity and magnetism courses would be very complex to arrange.

However, the physics engines controlling virtual worlds will only evolve with time, making them smarter and more accurate. Despite the initial difficulty in helping students to master these tools, they will likely become only more helpful in the long run for physics education.