16 Spilled Ink

CHAPTER SIXTEEN Spilled Ink Chromatography (noun). A way of separating a mixture of molecules. It's like a bunch of kids racing. At first, they're all jumbled up but soon they spread out, as faster kids take the lead. BIRDIE GRABBED MY POSTER BOARD, the one with the writing on it that said: Kate is bad at science. From her supply box, she snagged scissors. "What are you doing?" I cried. "I'm going to cut off a letter." "But that's going to mess it up." I bit my lip. "Kate, trust me. In order to get evidence, I need to cut. You can tape a piece of paper underneath and no one will know the difference." "Okay, okay," I said, hiding my eyes. "But I can't look." The scissors went snip snip. And then I peeked. Birdie had cut off a strip of the poster board with the letter K on it. "I'm getting a sample," she said. "To do some chromatography." "Oooooh, now I get it." When you see blue ink —it's way more than just blue. It's got a whole

bunch of colors swirled together to make that particular shade. Chromatography gives you a way to separate out all of those colors. And for detective work, it's awesome since each different kind of ink is going to have a different mix of color. "Now, we know that the culprit used some kind of blue pen," said Birdie. "But since Mrs. Eberlin gave out all different kinds of pens, this blue ink is going to be unique. Since no pen was the same, no ink will look the same once we separate it." "Just like a fingerprint," I said with growing excitement. "Exactly." Birdie grabbed a beaker and filled it with water. Then she taped the strip with the K to a pencil. It dangled like a little flag. "Watch," she said. "The water is a solvent. It's going to dissolve the ink and then it will spread across the paper." She hung the pencil over the top of the beaker so that the bottom of the strip barely touched the water. As the water soaked up into the paper, the ink spread upward. Biting my lip, I glanced over at the large strips of tissue paper hanging on Birdie's poster board.

The blue ink had spread upward but was no longer blue. It was pinkish at the bottom and light blue where ink bloomed upward. "Whoever thought a crime could look so pretty." I bent to inspect. "Now we need to test our suspects." Fifteen minutes later, we were back in Mrs. Eberlin's room for free read, where Birdie and I usually flop down in the beanbag chairs with our books. Instead, Birdie dragged me to the bulletin board and pointed to four different haiku poems written in blue pen. "I just need to steal those poems off the wall and test them!" "Keep it down. We'll get in so much trouble!" I looked for Mrs. Eberlin. She was going over some writing with Avery up at her desk. Today, Avery's lips were a sparkly lime green. Birdie shrugged. "We don't have any other choice. Unless you want to go tell Mrs. Eberlin." I shook my head. "No way. If I tell her, she'll tell Mom. And then it will be a big deal. Everyone will talk about how the principal's daughter is getting bullied. We've got to figure this out

ourselves." Being a principal's daughter has its perks, but it also has its downsides. "We'll just have to figure out some way to get the poems when nobody is looking," whispered Birdie. "Maybe after school?" I studied the bylines on the blue poems on the bulletin board: Avery, Jeremy, Elijah, and Rory. "We'll have to keep our eyes on them," I said. "Every one of them is a suspect." "Even Elijah?" Birdie asked. I gulped. "Even Elijah," Even though I didn't think that Elijah really could have done it. But he was the only one who saw me put the strawberry in my cubby... I had to be sure.