Play with objects on a teeter totter to learn about balance. Test what you've learned by trying the Balance Challenge game.

To display the results from the previous activity, each student designs and constructs a mobile that contains a duplicate of his or her original box, the new cube-shaped box of the same volume, the scraps that are left over from the original box, and pertinent calculations of the volumes and surface areas involved. They problem solve and apply their understanding of see-saws and lever systems to create balanced mobiles.

The application of engineering principles is explored in the creation of mobiles. As students create their own mobiles, they take into consideration the forces of gravity and convection air currents. They learn how an understanding of balancing forces is important in both art and engineering design.

Students explore the concepts of center of mass and static equilibrium by seeing how non-symmetrical objects balance. Using a paper cut-out shape of a parrot sitting on a wire coat hanger, they learn that their parrot exists in stable equilibrium — it returns to its balancing point after being disturbed. The weight of its tail makes the parrot balance upright. Give the parrot a push, and she knocks off balance, but swings back and forth until coming to rest in balance again.

Students write a biographical sketch of an artist or athlete who lives on the edge, riding the gravity wave, to better understand how these artists and athletes work with gravity and manage risk. Note: The literacy activities for the Mechanics unit are based on physical themes that have broad application to our experience in the world concepts of rhythm, balance, spin, gravity, levity, inertia, momentum, friction, stress and tension.

The concepts of stability and equilibrium are introduced while students learn how these ideas are related to the concept of center of mass. They gain further understanding when they see, first-hand, how equilibrium is closely related to an object's center of mass. In an associated literacy activity, students learn about motion capture technology, the importance of center of gravity in animation and how use the concept of center of gravity in writing an action scene.

Students use a simple seesaw to visualize solving a two- or three-step mathematics equation, while solving a basic structural engineering weight balance problem in the process. They solve two-step equations on a worksheet and attempt to solve the challenge of "balancing a beam" through hands-on problems. The use of sensor equipment for correct position monitoring aids students in balancing the structure, as well as balancing the equation as they solve it on paper.

Students are introduced to static equilibrium by learning how forces and torques are balanced in a well-designed engineering structure. A tower crane is presented as a simplified two-dimensional case. Using Popsicle sticks and hot glue, student teams design, build and test a simple tower crane model according to these principles, ending with a team competition.

To learn about the concept of center of mass, students examine how objects balance. They make symmetrical cut-outs of different "creatures" and experiment with how they balance on a tightrope of string. Students see the concept of center of mass at work as the creatures balance.