My classes just wrapped up studying balance. Students built (metaphorical) models to describe their understanding of center-pivot balance as well as off-center and massed-beam balance.

The project I assigned them was to build a mobile with a group of three or four members that both reflects who they are as individuals and is centered on some theme that unites them. Here are a few of my favorite mobiles.

EmojiMobile
“Emoji” shown next to the mobile diagram submitted by one team member. This mobile used relatively light weights and intriguing balance points (often quite far off center) to create the most interesting looking product in class. Nice attention to detail, the end product is pleasing to the eye, and the students all could demonstrate why it balanced.

 

BlackAndWhiteMobile
“Black and White” was a unique approach because instead of tying off masses, the team used clothes pins. The mobile was infinitely adjustable and pretty much was a rock-solid construction.
InitialsMobile
“Clay Figures” used a combination of materials, but especially clay, to share their interests. Fun fact about using clay to balance a mobile — as the clay dries, the balance can be thrown off as happened here. Two weeks later and most levels of the mobile are no longer balanced.

Materials:

  • 1/4″ and 3/8″ wooden dowels
  • A variety of string/twine/small diameter rope
  • Lightweight materials that can become masses on the mobile — don’t exceed 2kg overall if you expect to hang the thing in your classroom

What order should I have done this in? I saw two options:

Math first, building second: students draw a mobile, decide on which masses and will go where. Confirm that it should balance theoretically. Then get out the materials and build.

Building first, math second: students create a balanced mobile by trial and error. Then, apply the model of balance they created earlier in the course to prove why it balances.

We did option 2 and I was partially satisfied with the results. Several students reflected afterwards that they’d have preferred option 1 because they would’ve had an easier time building (that’s debatable, I think).