Harry opened up his backpack and reached for a napkin. He tucked it inside his shirt. Song Lee and Mary looked worried when he set the bag of heavy rocks on his desk. “Here I go!” he said. Then he reached into his backpack and pulled out a box of salt and shook some out on his tongue. “Mmmmm, poor man’s potato chips.” Sidney sat up. “What are you doing?” You’re not eating rocks. You’re eating salt.”