You could challenge a childs misconception regarding balanced and unbalanced forces by reinforcing the meaning of acceleration and movement. you could demonstrate this using an experiment such as the balloon experiment. the teacher could use an upright hair dryer and place the balloon on top of it. the forces would be unbalanced and cause accelleration where the balloon blows away and changes speed/direction.the teacher could then add paperclips on the opposite end of the balloon with cellotape, until the forces become balanced. when the forces are balanced, the balloon will hover about the hairdryer - keeping a constant speed and direction thus showing movement but where the forces are balanced.
