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Students creatively construct mobiles to balance oddly shaped objects while learning about the concept of the center of mass.

Finding the center of mass is a key factor in many engineering designs. For example, in designing cars, bicycles and all kinds of vehicles, and in designing tools and other objects to make sure that while they are in motion the objects behave as intended. balance center of mass mobile Concept of center of mass. Use their knowledge of center of mass and balance to build complex, free-hanging structures by balancing pieces with different weights at different points on a hanger. hangers various pieces of materials and objects with hooks on them Exploring the principles of balance and center of mass can be an interesting endeavor. Every object has a center of mass that it can balance on. Using this knowledge, children can build complex, free-hanging structures by balancing pieces with different weights, shapes and sizes. A day or two prior to the activity, ask students to bring in small objects of different shapes and materials to class. Gather materials. Prepare enough example display units so that each group gets one. A display unit consists of a hook attached to the top of the display/hanger and various objects with hooks with which children can create their own mobiles. Each piece can have two or more pieces hanging off either end. In this way, the original piece hanging from the hook can hold many more balanced pieces below it. Children are able to explore the center of mass concept and expressing their creativity in how they design their mobiles from pieces of different lengths and shapes. Divide the class into teams of three students each. Hand out a display unit to each group along with at least two extra hangers. Ask students to place the objects on the hangars at different points and then add them on to the main unit such that the entire stucture is balanced. Discuss the center of mass concept as students experiment to find balance using the various objects. Discuss real-life engineerig example in which center of mass is important to the correct functioning of products and tools. Project Evaluation: Grade team mobiles using a rubric with criteria such as the number of objects used, the number of different shapes and sizes of materials used and design complexity.