3–D Helium Molecule Tutorial
Alice Project
Duke University
Professor Susan H. Rodger
Gaetjens Lezin
June 2008
Introduction and Setup
In this tutorial, we will be building a 3–D electron cloud model
of a helium atom. We will also add a billboard that will serve
as a legend. Use paint or your favorite drawing tool to do this
step.
To begin, open a new Alice world and choose the sand
template.
Building the Nucleus (Adding Objects)
Select the object
SphereHighPoly, add four
of these objects into your
world.
Then click Done.
Click the green add
objects button.
Select the local gallery
and scroll over to the
shapes folder.
Hint: If you cannot find
the SphereHighPoly
Object, click search gallery
and type SphereHighPoly.
Building the Nucleus (Adding Objects)
Notice the four new items
on the object tree
Click and hold on the
shape to drag it
This is what your world should look like. Now line them up in a row by
clicking on them and moving them left or right.
They should be touching and half way sunk into the ground.
Building the Nucleus (Renaming)
Look at the object tree and right
click on the SpereHighPoly object
and select rename. Name it ProtonA.
Now select the properties
tab, click next to color,
and change it to red.
This is how your screen should look
after renaming and changing the
color of one sphere. Your spheres
may be in a different order. That is
fine.
Building the Nucleus (Renaming)
We want to name and set the second shape, SphereHighPoly2, the same way
we did the first one.
To do this, right click on
SphereHighPoly2, then rename it
NeutronA.
Then click the properties
tab and set the color to
yellow.
This is how your world should look after
renaming and changing the color of two
spheres.
Building the Nucleus (Renaming)
We are going to repeat the instructions on the last
slide for the third shape we added,
SphereHighPoly3.
Rename this object ProtonB.
Set its color to red.
Building the Nucleus (Renaming)
Now repeat the same steps for the last
sphere in the object tree.
Rename it NeutronB.
Set its color to Yellow.
Building the Nucleus (Resizing)
Now we want to resize the particles that make up the nucleus. There are a few
ways to resize items in Alice. We will use methods to reduce ambiguity.
Right click on
ProtonA. Click on
Methods. Select
resize.
Select other and type .5,
then click Okay.
Building the Nucleus (Resizing)
We want to make all the protons
and neutrons the same size.
So repeat the resize instructions
on the last slide for NeutronA,
ProtonB, and NeutronB.
The next step is positioning the
particles.
All the nucleus particles resized to .5 units
Building the Nucleus (Positioning)
Lets start off with the leftmost particle. This should be
ProtonB.
If it is not, reorder your line so you have in order from left to
right:
ProtonB, NeutronA, ProtonA, NeutronB
Once the particles have been resized it is easy to rearrange the
order.
Just click an object, hold, and drag it to where you want it.
Hint: Click on an object and its name will be highlighted in the object tree
Building the Nucleus (Positioning)
Once you have them lined up, we will move them.
Right click on ProtonB and select Methods.Select Move, then Up.
Choose Other, type 2
and click Okay.
Building the Nucleus (Positioning)
Now lets move the right-most
particle, NeutronB, up 2
meters.
Follow the same instructions
from the last slide.
NeutronB has moved up 2 meters
The next step is to put the 4 atoms
together.
We will use methods to adjust their
positions.
Building the Nucleus (Positioning)
Right click on NeutronB and
select methods.
Then select move toward.
Select 2 meters, then select
ProtonB.
The particles should look like this
when you are done.
Building the Nucleus (Positioning)
Now we will move NeutronA up 1.5 meters.
Click on NeutronA then select methods. Click
Move, then Up. Select other from the
dropdown menu. Enter 1.5 then click Okay.
If they are not touching, click on it and move it
until they are touching like the picture
shown.
Building the Nucleus (Positioning)
Now we need to move the last particle,
ProtonA , up. Click on ProtonA and select
methods, then move. Select up, then select
1.5.
Next we want to move ProtonA towards
NeutronA a distance of ½ meter.
Building the Nucleus (Positioning)
Right Click on ProtonA
then choose methods.
Select move toward.
Choose ½ meter, then
NeutronA.
Note: If they are not touching click on it and
move it so they are touching like the picture
shows.
Building the Nucleus (Positioning)
The last particle we need to position is ProtonB.
Right click on ProtonB and choose move toward.
Select 3/4 meter then choose Neutron B.
The world doesn’t look exactly perfect after
ProtonB is moved.
Use the move objects freely tool on the Add
Object screen to get it exactly right.
Electron Cloud (Creation)
Add another sphereHighPoly object to your world.
It is located under Local Gallery, then shapes. You should already be here.
If you can’t find it search for sphereHighPoly.
Electron Cloud (Creation)
Click on the object you just added and resize it by 2.
Then use its move method to move it up 2 meters.
Now change the opacity to 30% by clicking on the
properties tab, then clicking next to opacity and
selecting 30%.
Electron Cloud (Positioning)
Use the up and down tool on the Add Object screen and move
the electron cloud down a little by clicking on it and holding it
until the nucleus is in the center.
Electron Cloud (Positioning)
Now select the move objects freely tool to move the
electron cloud a little to the left.
Click , hold and drag the Electron
cloud a little to the left.
Electron Cloud (Renaming)
With the electron cloud in
place, we want to set all the
particles inside the nucleus
as a vehicle to the electron
cloud.
Before we do this, lets rename
the object SphereHighPoly
in the object tree to
ElectronCloud.
Electron Cloud (Properties)
Click on ProtonA on the
object tree.
In the properties tab click
next to vehicle and select
ElectronCloud.
Repeat this step for:
NeutronA
ProtonB
NeutronB
Electron (Creation)
We will add 2 electrons to the world. First navigate to shapes in the local gallery.
Click on SphereHighPoly and add it to the world, just like you have done before.
Right click on it in the world, select methods, then resize, then choose other and
type .5.
On the properties tab, click next to color and select green.
Electron (Renaming)
Now lets give a name to our
electron.
Like you have done before, go to
the object tree and right click on
SphereHighPoly and rename it
Electron1.
Electron (Positioning)
Eventually we will make the electrons revolve
around the electron cloud.
For this to work right, we have to position
the electrons in the proper place.
I will try and use methods to position the
electron, but you can also use the Move
Objects Freely button.
Click Add Object to get these options.
Electron (Positioning)
Right click Electron1 on the
object tree and select
methods, move, then up,
then other.
Type 4 meters and click
Okay.
The world should look like this once you have
moved Electron1 up 4 meters.
Hint: Click and move electron1
to resemble the picture.
Electron (Creation)
Go back into Add Objects then to Local Gallery.
Go into the Shapes folder and add another sphereHighPoly object.
Change the color to green.
Resize it to .5 meter and rename it Electron2.
Electron (Properties)
We want to set the vehicle properties of
Electron1 and Electron2 to the Electron
Cloud.
So click on Electron1 on the object tree.
In the details panel, click on the properties tab
and click next to vehicle. From the drop down
menu select ElectronCloud.
Repeat all of the previous steps on this slide for
Electron2.
Model (Positioning)
Now all the properties are set up. We just need to position the entire model so
that it is in the middle of out screen.
To do this use the Move Object Freely button.
Click on the ElectronCloud
in the world window and
move it backwards.
Next click on the Move Objects Up and Down
button and move it up a little bit. Notice all
the sub atomic particles move with the
electron cloud.
Coding (Setup)
Click Done to go back to the initial Alice window.
Next we will code the model so that the electrons revolve
around the electron cloud together.
To do this, we will put the electrons in a list so it is easier to
move them together.
Coding (List)
First click on the world tab on the
object tree.
Click on the properties tab, then
click on create new variable.
A window will pop up.
Type Electrons in the name box.
Click the radio button next to Objects.
Click the check box that says make a list.
Add two new items to the list by
clicking on new item twice.
Coding (List)
Click next to <None> and select Electron1.
Click next to the second <None> and choose Electron2.
Then click OK.
Coding
Now drag a For all together
statement into the editor
window.
From the drop down menu
select expressions then
World. Electrons.
Then click on Electron1 on the Object Tree.
Then click on methods in the details panel.
Coding
Scroll down to the
statement that says turn at
speed.
Drag and drop this into the
For all together statement.
From the drop down menu
select forward.
Then select .25 revolutions
per second.
Coding
Now lets drag the tab that says item_from_Electrons from the For all
world.Electrons statement.
Drop it over Electron1 in the turn at speed statement.
At the end of this statement click the triangle facing down next to more.
Select asSeenBy, then ElectronCloud.
Coding
Click the triangle next to more again
and select duration.
Choose other.
Put in a large number like
1,000,000,000.
Click Okay.
Hint: Press play, You may need to reposition
the electrons if they don’t revolve properly
Finish Touches
You may want to move Electron2 a little
further away from the
ElectronCloud. Simply use the Move
Objects Freely button to do this.
Also you may want to add a billboard
that is a legend of what each piece
of your model represents. For
example, I used paint to create this
legend.
Save the Picture as any one of the
following; JPEG,PNG,BITMAP,GIF.
Alice will accept all of these formats.
Finish Touches (Billboard)
To add this billboard to my world I will
click on file then choose Make a
Billboard.
Then I go to the folder where the
picture I created using paint is located,
click on it, and then hit Import.
Note: Place the billboard where you
want it.
Final Image
I hope you enjoyed my tutorial.
Have fun with Alice!!
:-D