“Are you ready to run a Mystery Box investigation with me?” Shawna Winter asked as her 22 kindergartners gathered around her. The classroom erupted into cheers. “Look at all these different eating utensils I’ve brought from home.” She pointed to two identical sets of spoons and forks made of three different materials. Each set was lined up in a row in front of a wooden chest a little bigger than a toaster. The box was latched shut with a heavy lock, and next to the box was a key tied to a long ribbon (see Figures 4-1 and 4-2).
“One set of these utensils is going to be mine, and the other set is going to be yours,” Ms. Winter said. She quickly established with the children the names of each of the utensils and the material it was made of. “So,” she summed up, “we have a plastic spoon, a wooden spoon, and a metal spoon, as well as a plastic fork, a wooden fork, a metal fork.”
“Now I’m going to take my whole set away,” she said, scooping up one row of the spoons and forks and tossing them into a bag. “Then I’m going to take one item—just one—from my set and put it into the Mystery Box. Close your eyes. No peeking!” All 22 kindergartners gleefully covered their eyes.
Ms. Winter turned her back to the kids, unlocked the Mystery Box, selected an item from her bag of utensils, and locked it inside the box with the key. The students’ set of six items—forks and spoons—remained lined up in front of the Mystery Box.
“Now open your eyes,” she said. “Inside the Mystery Box is one thing taken from my set of objects, which is just like your set. And here’s the amazing thing. You’re going to figure out what is inside the Mystery Box just by asking me questions.” Then, very dramatically, Ms. Winter uttered the words she always used to start the Mystery Box
game. “If you ask me a question about what’s inside the Mystery Box, I will tell you the truth.”
“I know,” said Maya. “Is it the plastic spoon?”
“That is a very good question, Maya. Do you know why it’s a good question? It’s a good question because … it’s not the plastic spoon.” Several kids giggled; a few sighed with disappointment.
“So Maya’s question has taught us something important,” Ms. Winter said. “Whatever is inside the box, it is not a plastic spoon. So that means we don’t need this one here anymore.” She picked up the plastic spoon from the students’ set of utensils and put it on the table, out of sight.
Ms. Winter reached into a cup of Popsicle sticks that had all of the children’s names written on them, which she used to ensure that each child had an equal chance of getting a turn. The stick she pulled from the cup had “Carlos” written on it.
“Carlos, what question do you want to ask?” Carlos was new to the classroom, having moved to