contents Virtual Mobile explore

Have you ever tried to balance a mobile made of sticks and objects hanging from threads? Have you ever touched or blown at a mobile and watched the beams slowly swinging?

Alexander Calder was an artist who created huge, beautiful mobiles that hang today in many museums. He once said, "To most people who look at a mobile, it's no more than a series of flat objects that move. To a few, though, it may be poetry." Calder's mobiles inspired Zack Simpson to create a Virtual Calder mobile which he has kindly shared with Math Cats.

mobile by Alexander Calder. © The Calder Foundation.

Now you can play with a mobile right on this page! You can add lots of beams and change their length and position. You can change the size and color of the balls. You can get the mobile to follow your mouse or watch as beams and balls randomly morph in size and position.

But... can you get it to do what you want it to do?   Have fun trying!!
(Instructions are below the project.)

* Instructions

At first, there is only one beam which supports equal weights on both ends. To add a new beam, press "New Beam" button.

Click on the weight and it will begin to blink. Then click and drag the mouse anywhere inside the gray area to scale the weight and the length of the arm.
  • Drag left to shrink the weight.
  • Drag right to enlarge the weight.
  • Drag up for a shorter arm.
  • Drag down for a longer arm.
Hint. You can drag the mouse until you have the size and length you want, then release the mouse and scale again.

To adjust the hanger arm position and length, click on a smaller vertical arm to select it; it will flash. Now click somewhere else and drag the mouse to scale it.

  • Drag left and right to change the position of the arm relative to the parent beam.
  • Drag up and down to change the length of the hanger arm.

The "random morph" will make the current piece slowly change over time.

The color wheel lets you change the color of a flashing weight. The scroll bar changes the brightness.

Thanks to Zack Booth Simpson for creating this great applet and sharing it with
Math Cats! You can learn more about Zack and his work on his home page and at    (We love the videos of interactive shadow exhibits!!)

copyright 2003 - by Zack Booth Simpson.   Shared on Math Cats with permission.