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Quick Tip: How to Illustrate an Atom


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In this QuickTip you will learn how to use the Stroke Width tool in Illustrator CS5 with Layer and Gradient techniques to make a scientific illustration of an Atom. Let's get started!


First, some words about the physics of an atom. An atom, as you perhaps know, consists of the nucleus and electrons which are rotating by their orbits. The nucleus consists of protons and neutrons. The quantity of protons is equal to the quantity of electrons. Every proton is approximately 1836 times bigger than every electron. Every neutron is somewhat bigger than every proton, with that in mind, let's start.

Step 1

Take the Ellipse Tool (L). Create the circle with it. Set the Stroke of the circle to None. Fill the circle with the Radial gradient filling, which is shown on the diagram below.

Change the colors of the filling to the red hues: from the lights in the center of the circle to the shadows on its border.

Step 2

Move and increase the light portion of the gradient in the circle as you can see it on the following diagrams.

Then copy the circle (Command + C then Command + V) to make the following picture.

Step 3

Change the colors of the gradient filling in the two copied circles. Choose blue and green tints.

Then increase the size of the green circle and decrease the size of the blue one.

After that, copy the red circle two times, the blue circle two times, and copy the green circle three times (Command + C then Command + V). You should have a picture the same as below.

The red circles represent protons, the green circles represent neutrons, and the blue circles represent electrons.

Step 4

Go to the Layers palette and organize the layers so as you can see it on the diagram. That is, all the electrons must be placed on the top. One of the neutrons must be located in the bottom, and all the protons must be placed above the bottom neutron. Use the image below for reference.

Then take the Ellipse Tool (L) and draw a helping circle with it. After that, place all the neutrons and all the protons in that circle. You don't need to do it exactly. You need only to create the rounded form of the atom's nucleus. See the diagram for an example.

After that, you can delete the helping circle.

Step 5

Take the Ellipse Tool (L) and create the first elliptical orbit's contour for an electron.

Go to Object > Transform > Rotate and create two elliptical orbits by clicking the 'Copy' button.

Take the Direct Selection Tool (A), select the top anchor point on the first elliptical path (electron's orbit) and convert it to a corner one. See the image below.

Then take the Scissors Tool (C) and click on the anchor point.

Then with the aid of the Direct Selection Tool, move the right anchor point to the bounds of the nucleus.

Repeat the previous steps with the left anchor point.

Repeat the step again, with all the elliptical orbits. You should have an image like the one below.

Step 6

Take the Stroke Width Tool (Shift + W) and by clicking and dragging the bottom anchor point of the first elliptical orbit, increase the width of the line.

Then set the Stroke Width to 15px (depending on the size of your Illustration, you may want to change the value).

Do the same for the two other orbits. But set the Stroke Width for them to 12px (depending on the size of your Illustration, you may want to change the value).

Step 7

Select all three electrons' orbits and go to Object > Expand Appearance.

Pay attention to the points of the orbits where the orbits touch the atom nucleus.

By using the Direct Selection Tool (A) and the Pen Tool (P) (for deleting the superfluous anchor points), create the points of lines to something similar to the one shown on the diagram below.

Step 8

Fill the expanded orbit with a 'Light Gray-To-Dark Gray' Linear gradient. Set the angle to -90 degrees in order to convert the near tint of the gradient color to dark gray, and the remote hue of the gradient color to light gray.

Set the Opacity for all the elliptical orbits to 65%.

Step 9

Place the electrons on their orbits.

Step 10

Now click on the 'Document Setup' button.

Go to the Transparency part. Check the 'Stimulate Colored Paper' option and click on the white rectangle.

Choose any color you like.

You will now have a picture similar to the one below, the workspace should be filled with the chosen color.

Step 11

Take the Type Tool (T), click on the Workspace, go to Character menu and choose the options of the font as you want.

Then type any words you like, select them and rotate. I have typed the name of the shown atom and the famous formula of Albert Einstein which shows the correlation between mass of substance and the full energy of it.


So, you have just made the atom of Lithium which consists of the three protons, three electrons and four neutrons. I hope you enjoyed this tutorial.