1 The Great Unknown Assembly

Kate THE CHEMIST THE STEM NIGHT DISASTER DR. KATE BIBERDORF WITH HILLARY HOMZIE MAKE YOUR OWN LEMON BATTERY! EXPERIMENT INSIDE!

CHAPTER ONE The Great Unknown Assembly Inference (noun). The process of drawing a conclusion based on evidence. Like if your little brother has cheeks full of crumbs, you can infer that he just ate the last cookie. WAITING WAS TORTURE. The entire fifth grade sat in the auditorium. Any moment the administration was supposed to make a huge announcement. I bounced in my seat. I twirled my hair. I sucked in my cheeks. "C'mon, Kate," said Elijah Williams, one of my closest friends. "Tell us what's going on." "I wish I knew." I had to practically shout. All around us students were chatting and chairs were squeaking so loudly I could barely hear. Birdie Bhatt studied the white cinder-block walls. "Maybe we're going to paint a giant mural." This didn't surprise me. Birdie and I had been BFFs since kindergarten, and she was all about art.

Next to me, Memito Alvarez patted his middle. "I hope they're going to announce a cooking club." "Doubtful." Avery Cooper shook her head and her blonde braids swayed. "I think they're going to make the cafeteria go completely green. My student council committee has already drawn up a proposal." "No plastic straws or paper napkins," explained Phoenix Altman from the row in front of us. "And more options for vegetarians." "I'm fine as long as there are no Brussels sprouts." Jeremy Rowe leaned back in his chair. "Bet you a dollar none of you are right," he said, smirking. "I haven't guessed anything yet." Elijah pointed in my direction. "I'm going to go with whatever Kate thinks. 'Cause of Mrs. Crawford." Of course, at that moment, it got quiet enough so everyone could hear Elijah. All the kids looked at me. Even the rows farther away. That was because Mrs. Crawford happened to be the principal of Rosalind Franklin Elementary School. And she also happened to be my mother. But truly, I had no idea what was going on. Ms. Gottfried, the librarian, who was our audio-visual guru, adjusted the height of a

microphone in front of the stage area. A banner below the scoreboard read: Today is THE day! "C'mon, Kate," insisted Elijah. "Tell us what's up." I wracked my brain. "I really don't know." "What does your gut tell you?" Phoenix leaned forward, her parrot earrings swishing. "That I'm super hungry," joked Memito. "I only had one waffle for breakfast and it's almost lunchtime." We all laughed. "Just guess what you think is going to happen, Kate," pleaded Elijah. "Scientists don't guess," I said in my most patient voice. Elijah, who is my next-door neighbor, has heard me say this about a billion times before. "Guesses are often random." You see, I'm interested in science—chemistry, especially. Actually, strike that. I'm obsessed. Because chemistry is everything. It's everywhere. It's how your stomach breaks down the candy bar you've just inhaled. How laundry detergent scrubs the dirt off your socks. Why popcorn pops in your microwave and tastes so yummy.

Birdie gently poked me. "Then make a hypothesis." A hypothesis is an explanation that can be tested. I think about the most recent observations I've made surrounding the mystery at our school. Unfortunately, I haven't had time to test out anything. "I could make an inference." I shrugged. "You know, come up with an idea based on evidence." Ms. Gottfried tapped the microphone. "Testing," she said. "Testing, one. Two. Three." The microphone wasn't working. We could barely hear Ms. Gottfried's voice from across the auditorium. Kids whipped around to look up front. Some students in the back were getting squirmy. The chatter in the room grew louder. Jeremy's gaze followed the teachers scurrying up front with clipboards. "The assembly is going to start any second," he said. "If you want to win the bet, you've got to make your predictions right now." "You mean, make an inference." I grinned at him. "Yeah, yeah, whatever." Jeremy shrugged. "An inference, then." That got me thinking about all of the observations I had made in the past week. I definitely knew there was a mystery going on

around school. And I was about to use my powers of observation to figure it out!