L EA N CE N R TI V OR 2.2 DOUBLE R TAP I N TO G ZOOM TE WITH AC PHONE I TY TABLET CHILD-DESIGNED INCLINES PhySicS Materials  flannel or magnetic board  4 to 8 small ramps (see description)  several small balls  Velcro or magnetic tape Center Description This center allows children to experiment with the effects of changing the slope and direction of inclined planes. It integrates concepts from physics and geometry. The activity is similar to marble-track toys that children may have played with in the classroom. This activity, however, gives children more control in the investigative process; therefore, it allows for more scientific learning. The center consists of either a flannel or mag- netic board, mounted to the wall or propped vertically; four to eight small ramps, constructed by the teacher; and small balls to roll down the ramps. Depending on the type of backboard being used, the ramps have either Velcro or magnetic tape affixed to one of their sides. This allows children to position the ramps wherever they like on the backboard. Children can change the angle, position, and direction of each ramp segment and observe how the change affects the movement of the balls. There are many inexpensive and simple ways to make the ramp segments for this center. Perhaps the easiest method is to cut the lips off of the short ends of jewelry gift boxes that are approximately 8 inches long and 2 inches wide. Affix the Velcro or magnetic tape to the long edges. Each jewelry box makes two ramp sections if the tops and bottoms of the boxes are used. Empty jewelry boxes can be purchased at craft or party supply stores. Another quick way to make ramp segments is to cut plastic or wood corner molding approximately 1¼ inches wide into 8-inch lengths. Overlap two strips and glue them together so that there is a lip along 20 c ha P TE R 2 each side of the ramp to keep the balls from rolling off the edge. Easier still is to use a plastic ceiling wall bracket, also 1¼ inches wide and cut into 8-inch strips, since it already has lips along both edges (see photograph). (Ceiling wall brackets are the long, horizontal pieces used to hold suspended ceilings.) All of these materials are inexpensive and are avail- able in hardware or building supply stores. Science Content An inclined plane is one of six types of simple ma- chines that children encounter daily in their lives. It consists of a flat surface positioned at an angle (less than 90 degrees) in relation to a horizontal surface. In other words, one end is higher than the other. Chil- dren experience inclined planes at entrance ramps to buildings, sloped sidewalk intersections, and when they run, slide, or roll down a hill. From a scientific perspective, inclined planes allow individuals to slide or roll objects from one level to another. This requires COPYRIGHTED MATERIAL