Matthew's latest ambition is to become a firefighter. So that evening, when he and his mother enjoy a July long-weekend barbecue, Matthew supervises his mother carefully. "These coals stay hot for a very long time," he reminds her. After watching the fireworks, Matthew goes to bed, still thinking about fire safety as he hears the sound of the last hissing rockets zoom up into the sky. Before he knows it, Matthew is wide-awake. A rocket...