Car Rolling: Use a long strip of carpeting, a strip of poster board, a strip of poster board with sandpaper glued to the surface, a strip of poster board with bird grit glue on it, and different cars. Have the children roll their cars on the different surfaces and compare how the cars roll on each surface. Which surface, for example, allows the car to roll the farthest? Compare how different sizes and shapes of cars, and different surfaces, make cars roll differently. For more information on this activity, see Squish, Sort, Paint, and Build, page 77.