Ideas for Educational Exhibit Builders in Second Life

The Splo is the oldest an interactive science museum in Second Life. The Splo calls itself a museum of science, art, perception and humor, its mission is to provide visitors with an opportunity to actively explore and learn while having fun. Staff members of the Splo have built over 100 exhibits. As we have built exhibits we have made some discoveries about creating educational experiences in Second Life we would like to share with others. So here are two dozen ideas to use while building exhibits.

Allow Visitors to do the wrong things.

Domino Fall

Domino Fall

Allow freedom at your exhibits to do the “wrong thing” they will sense that they have the ability to freely explore. In the exhibit “Domino Fall” it is possible to knock over a small domino so that it hits a larger domino which knocks over a larger domino and so on. This is fun to watch, but, we built the exhibit so they can push over any domino in any direction, Many visitors push over the largest domino which falls launching the smaller dominos all over the place. There is a wonderful joy in creating chaos.

Physical prims float above other prims.

Exhibit: Domino Fall

physical domino floatsDomino with phantom prim
In the first image a physical domino hovers over a prim floor. In the second a phanton prim fills the space.

This looks annoying to a physicist. However they do not float over phantom prims, so once you have made your physical prims you can slide a phantom prim underneath them to make it look like they are resting on the ground. We use a phantom prim underneath all the dominos in domino fall. Note, the phantom prim cannot be linked to a non-phantom root prim or it will become non-phantom.

Anti-Lag: The Dominos are regular prims until one of them is touched, it then sends a linked message to all the others causing them to become physical and temporary. Physical prims cause lag as they collide with other prims. Temporary prims vanish after a minute. Linked messages do not cause the lag of listeners.

Test exhibits with an alt that belongs to no groups

If you make a physical prim and expect other avatars to be able to move it check the "Allow anyone to move"  box when setting the general parameters of the prim.

If you assign the object to a group then anyone who is a member of the group can move the prim but other visitors will not be able to move it. Your avatar who belongs to no groups can test whether the prim is moveable. The usual hand appears over the physical prim but a lock then appears when the avatar does not have permission to move it.

Exhibits: Two disk roller
Exhibit: Domino Fall (see above)

two disk roller

Script objects so that they work in all orientations

Click on the spacecraft bottom right to rez a relativistic spacecraft moving in the direction that the fisrt spacecraft is pointing.

Exhibit: Relativistic Spacecraft

Here is a script fragment to handle rezing an object with a specified rotation moving with a velocity in a given direction parallel to the direction another prim is pointing.

vector pos = llGetPos();
vector offset = <0.675,0.0,1.0>;
vector vel = <0.0,0.0,1.750>;
rotation rot = llGetRot();

When rezing a moving object so that it moves in the direction the rezing object is pointing, multiply the velocity vector by the rotation.
To orient the new object so that is pointing the same direction as the obeject that rezes it, just specify the same rotation, rot.

llRezObject("dynasoar", pos + offset,vel * rot, rot ,1);

Allow visitors to ride things.

We built the Moocault Pendulum so that people could ride it, it adds one more point of interaction to the exhibit.


Exhibit: Brownian Motion (See below)
Exhibit:Newton's Cannon

Newton's Cannon thumbnail

Riding the cannon ball one orbit later
Ride the cannon ball out of newton's cannon and around the earth.

Exhibit: Light Balls

sun earth ride
Ride a ball of light from the sun to the earth.

The ride would take 8 minutes, and that was too long so we allowed people to take the ride at 8 times the speed of light. Here the avatar is approaching a planet.

Exhibit: Tour Hovercars
Exhibit: Balloon Tour
Exhibit: Doppler (See below)
Exhibit:Big Bang
Exhibit: Moocault (See above)

You can also take control of the avatar once they sit, I use this to turn an avatar upside down to view an image that changes when it is inverted. In a real life museum the photo would be turned over, in Second Life turn over the avatar.

Patio oitaP

Patio oitaP triptik

It is even better if the visitor can control the objects while they are riding them.

Exhibit:Hover Pies

The flyable hover pie is used as a pun when we celebrate pi day on March 14 every year. We installed a free vehicle control script in the pie.During the event we had several avatars zooing around on pies. The pies vanish when the avatar dismounts to avoid clutter.

Particles are your friends.

Coriolis Fountain

Coriolis exhibit coriolis fountain real
In this exhibit a ball orbits the ring. It spits out particles as it orbits. The particles travel in straight lines! but the array of particles forms a curve.
This exhibit is extremely difficult to build in real life, although it has been done at Tom Tits Experiment, an excellent interactive science museum in Stockholm where water squirts onward from rotating tubes.

Exhibit: Doppler

doppler effect
In the doppler exhibit avatars ride balls which emit circles of particles at regular intervals, just as sound wave crests are emitted from moving sources.

Particles are created on the clients side computer i.e. on your computer .They do not lag the sim. Particles are created by a command in Linden Scripting Language, LSL. You can learn to use particles at the particle laboratory, SLURL, You can also use a website to automatically create the script you need to make the particle effect you want. URL
            In our coriolis exhibit particles are launched in a straight line at a constant velocity from a prim that is moving in a circle. The pattern of particles appears to be a spiral, and yet, each particle moves in a straight line.
Remember, One prim can make only one particle effect.

Exhibit:Magnus Effect

Magnus Effect

Magnus Effect

Exhibit: Eclipse Umbra

eclipse penumbraeckipse umbra

Particles pass through prims, however, particles can be sent out in a hollow cone patern which makes it seem like they are blocked by an object with a circular cross section.

Exhibit: Light Clock

Partcles seem to bounce off mirrors in this light clock.
In a second light clock particles track the motion of a prim that bounces off mirrors. See the cure for prims that pass through walls below.

Exhibit: Questionmark

questionmark particle circles and spirals

Particles can be textured, the good thing about his is that the textures although planar, will always rotate to be viewable by the observer.

The particle questionmark replaced this 3 prim one that didn't work.

3D question mark

You can Stream Live video into SL

eclipse 2006

Exhibition:Live Eclipse Coverage

Make social experiences.

An important part of all museums is the ability for groups of people to interact with an exhibit together.

Exhibit: Events: Eclipses, Transits

Exhibit: trampoline

Groups include classes

Exhibit Brownan Motion

NMU class visits Brownian
A college class interacts with the brownian motion exhibit.

Target Omega rotation

Target Omega rotation is on the clients computer, it does not lag the sim. But each person will see the rotation at a different position.

Exhibit: Rotating Café Wall Illusion

Rotating Cafe Wall Illusion

Rotating Cafe Wall Illusion

The rotating cafe wall was the first exhibit I built in SL, shortly after it was copied from SL and made real by Heureka science museum in Helsinki Finland. The first example of an interactive science exhibit first built in Second Life that was made in real life. See a video of the real exhibit here:

Exhibit: Dipping Birds

dipping birdsdipping bird up
            In Second Life we scaled up the desktop dipping bird to bigger than an avatar. We make it dip by using the target omega call in LSL, we alternate the clockwise and counterclockwise rotations every couple of seconds. The problem is that the rotation can drift to new positions slowly over time if the clockwise and counterclockwise rotations do not last for exactly the same length of time. To cure this you can reset the position of the rocking object to the initial position after every cycle. There is a problem though, since the rotation is purely client side the object already thinks it is in its initial position so nothing happens. To cure this set it to a new position very close to its initial position then set it a second time to the original position. This will actualy reset the position. It also synchronizes all viewers who are watching it at the same time.

It is posible to rotate an object not about its center.

We use this with the hyperbolic slot to revolve a stick and have it pass through a slot.

Hyperbolic Slot

Hyperbolic Slot

Use touch position detect to save prims and to make controls

There is a recent command in LSL that allows you to get the coordinates of the point at which you are touching the face of an object. Previously your would need several prims to make a number of different buttons, now you need just one prim.

Exhibit: Circles or spirals

Texture Animation rotation is used in circles or spirals

Exhibit: Doc Edgerton Cuts the cards

doc edgerton cauts the cards
Choose a bullet speed using a slider, then touch the gun to send a bullet through the card.
The slider position is read from where the avatar is touching the slider control.

This exhibit shows that in an SL museum you can do things ou would never do in a RL museum.

Use plant technology to display science.

Exhibit: Electric dipole

Electric Dipole Tree

Electric Dipole Tree

Exhibit: Magnetic dipole

Magnetic Dipole Tree

Magnetic Dipole Tree

Exhibit: Electromagnetic wave bench

Electromagnetic Wave

Electromagnetic Wave Bench
Above the image of a photon of light, another photon is emitted by one atom and absorbed by another.


Scripting Brings Exhibits to Life

Almost every exhibit contains a script.
UNote t5hat you can use multiple scripts in one prim.

Exhibit: Moocault Pendulum(See above)

The Grey Goo Fence

To protect against Greifers Linden Labs restricts how quickly one prim can rez other prims. In an exhibit like Chain Reaction where we need to launch 128 ping pong balls the grey goo fence could slow the exhibit. To get around it we rez all the balls as transparent prims during a slow reset time, we set their alpha to 0 in a script. Then when we need the balls we simply make them visible.

non physical (2x the dings)  then make them physical  64 traps 2 balls each for 128 balls if physical grey goo count is 256

but 128 was still high  so link 2 balls score is 64 then unlink and go physical

Exhibit: Chain Reaction

Chain Reaction

Chain Reaction

Physical Prims can sometimes Pass through walls

In an exhibit which has a prim that collides with a wall sometimes the prim will pass through the wall.

You can fix this by looking for collision end and then doing a check for which side of the wall the object is on.

Exhibit: Brownian Motion

Brownian Motion

Brownian Motion and Tracker

Exhibit: Light Clock

Use Animations

Animations and poses enhance the participation of the avatar in the exhibit.

Exhibit: Cat Fall

cat fall



Exhibit:  Vitruvian Avatar

Vitruvian Avatar Reba Rutabaga

Exhibit: Spin


You can preload sounds, one preload per script, so that they are ready to play when triggered by an avatar.

You can control sounds by restricting them to a parcel.

Exhibit: Find the Highest Note

Find The Highest Note

Exhibit: Doppler Sheep

Exhibit: Sexy pi phone

Exhibit: Speakers in Destination Mars

Destination Mars

Destination Mars imagetransparent speakers destination mars
The transparent cubes in this mage are invisible seakers  that broadcast the sound of the meteorite collision nto the sim.

3D animation using alpha

You can animate 3D objects by controlling their transparency. Cycle through a set of objects making one of them visible at a time. There is a 0.2 second delay each time a script changes alpha of a prim, to speed up the animations use several scripts.

Exhibit: Perpetual Motion

perpetual motion wheel

You can make scripts behave differently for prims rezed from another prim and prims rezed from inventory.

For example you may want prims rezed by another prim to vanish after a short time, but need to have them NOT vanish when you rez them to  work on them. always pass a rezed prim a parameter other than 0.

Exhibit: Gravity Well

gravity well new
The yellow ball that rolls around the gravity well is rezed by the blue box in the center. It is rezed and then dies in a minute. When the orbit ball is rezed from inventory it does not die.

Exhibit: Relativistic Spacecraft

Use Flexi Prims

In real life a whirly is a flexible corrugated plastic tube that sings when it is spun. A whirly can be made in second life by creating a flexi cylinder.

I combine the flexi whirly with an animation that is part of a gesture. When the gesture is triggered the avatar spins and the sound of the whilry is played.

flexi whirlyflexi whirly

Use prim torture to make special shapes

To make a thin wall use a dimpled sphere

Far Out Corners

Far Out Corners

Frames of Reference

Second Life camera controls allow you to show a visitor the view from a frame of reference of your choice.

Exhibit: Big Bang

Have things clean themselves up

signs with timers


Don't Forget Humor

Exhibit: Collision Sounds in SL

plastic collision sound flamingo




Craters or Domes

Craters or Domes

Distorted Room


Divided Attention

Divided Attention


Echo Tube

Echo Tube






Patio Plasma

Copyright 2009

20 August 2009