Lesson Summary Students continue their work with balance in this lesson using cardstock objects and clothespins as counterweights.  Students are introduced to the concept of stable balance and work to identify where the clothespins should be placed in order to create a stable balance. Teacher Background Students learn that a stable position is one in which the object is not falling over.  They learn that the point an object is balanced on is its balance point.  Additionally, students come to understand that the counterweights need to be placed low on an object to create a stable balance.  They learn this by trying to balance the arch and triangle several different ways. Set-up/Management Tips This lesson will take one hour or 2 30 minute sessions.  If breaking the lesson into two parts, break after students make their predictions on the Stable Positions sheet. Be sure to copy the Stable Positions sheet prior to the lesson.  It can be found in the manual under Investigation Duplication Masters. The kit comes with the cardstock arches and triangles pre-cut.  Check these before the lesson; don’t use any with bent parts.  You will be using craft sticks taped to student desks as the balance point in this lesson. Before class have chart paper ready for recording content chart items. Literacy Support Books Available Through VAST Mediagraphies: Books Available Through VAST Mediagraphies: (see Literacy Links) Science Stories There are no Science Stories with this lesson. Scientific Vocabulary The following words are key vocabulary words that will be introduced in this lesson and reinforced throughout the unit: Stable  Arch    Triangle Balance Point