7 A Fruitful Search

CHAPTER SEVEN A Fruitful Search Power (noun). How fast energy is transferred from one spot to another. The faster something gets transferred, the more power. So, think of it as a faster runner in a race having more power than a slowpoke. "THIS IS GOING TO BE SO COOL," I said, fiddling with the arms of Liam's robot. "I'm using a piece of fruit to power up my little brother's favorite toy." I moved the little levers. Everyone in my STEM group leaned forward for a better look. "Whoa! That's amazing," exclaimed Memito. "Thanks." I hadn't tried out the battery yet and was eager to get started. I couldn't believe how far ahead both Phoenix and Memito were. And Birdie and Avery, too, from the looks of it. I didn't like feeling behind. As Avery walked by to sharpen her pencil, she studied the lemon and then the robot. "Is that really going to work?" she asked. "Oh yeah!" I promised. Ms. Gottfried strode closer to get a close-up on the lemon. Turning, I gave her my best smile.

"My dad calls his car a lemon," said Jeremy. "But turning an actual lemon into a battery? That doesn't seem possible." "Come closer." I motioned to Ms. Gottfried. "See. I'm going to get this battery started." I pushed a shiny nail into one side of the lemon. It didn't puncture the skin until I jammed it in with a good shove. "It's coated in zinc." I waved a piece of wire. "My mom helped me cut a piece of this." I pushed it in easy peasy. "The wire is copper. You can also use an old penny. See, the zinc wants to wave bye-bye to the electrons. And the copper wants to collect them. When the electrons zip along—you get electricity. Which is going to power up this little robot." I patted the lever-like arms. From a nearby table Rory hooted, "Go robot power!" And I heard Birdie cheering, too. Using alligator clips, I connected the zinc nail and copper wire to the place where the old battery had been in the robot. "Let me zoom in on this," said Ms. Gottfried. "All right," I said. "Ready, get set! Go!" Nothing. The robot didn't budge. "Maybe I put the positive side on the negative side," I said. "The red goes on the positive. And the black goes on the negative."

Avery whirled around from the table next to ours. "Do you have them on correctly?" She puckered her lips, which were blueberry blue from her lip gloss demo. "I know I did the battery right." I gritted my teeth. "You'll figure it out," said Elijah. "I sure hope so," I murmured. "I'm going to go over and take some photos of the other projects," said Ms. Gottfried. "Okay." I smiled but inside I felt like such a fool. My cheeks warmed. "I can't believe it didn't work." Taking a deep breath, I tried to relax. "Let's meet over by my desk," said Ms. Daly in a gentle voice. I dragged over to Ms. Daly, whose desk was more like a counter in the front of the lab. "Kate, what do you think happened?" she asked. "Maybe it's a bad lemon. I read that before you stick in the copper and the zinc, you're supposed to squeeze the lemon. I forgot!" "Okay," said Ms. Daly. "Did you think about how much power it takes to start a motor on a robot though?"

"No," I admitted. "I didn't even think about that. I should have probably tested how much power I needed." "That's what I wanted to show you." Ms. Daly grabbed a small black machine off a shelf above her desk. "I have a voltmeter. We can test the voltage of your battery." "That's awesome!" I had no idea that even existed. I wanted to borrow it and test the power of everything! Ms. Daly placed the red probe tip on the copper. "Now you put the black probe tip on the zinc." After I touched the black probe to the nail, the screen of the voltmeter read 0.912 V. "Probably not enough energy to power the robot," I said. "Is the V for volts?" "Yup." Ms. Daly closed her eyes as if counting in her head. "If my math is correct, it would take over one thousand lemons to get that robot moving. You're going to need a lot more juice, if you want it to run." I let out a low chuckle at Ms. Daly's corny joke. But inside, I was kicking myself for not thinking this through. I definitely needed to find something that used a lot less electricity than this robot. But what? My eyes scanned the items on Ms. Daly's

desk. I spotted a simple-looking calculator. "Could I use that?" "Of course," said Ms. Daly. "Thank you so much." I waved the calculator in the air and called out to my group as I headed back to the table. "You guys, I'm going to use my lemons to fire up a calculator." I tried to sound happy but I was more than a weensy bit disappointed. A calculator was definitely not as cool as a robot. It might even be a little bit boring. "I guess I really should have tested this"—I pointed to the lemon—"out first." "You know what they say," said Jeremy. "It's always best to test." "Who is they?" asked Phoenix. Jeremy thumped his chest. "Me!" When he did that, my lemon knocked to the floor into a pile of sticky dirt that had fallen out of Phoenix's project earlier. Groaning, I pulled the zinc and copper out of the lemon. "When you get a lemon," I said, "sometimes you just have to make lemonade." Then I squashed the lemon under my foot, which felt good. I couldn't help feeling a little upset at the lemon, even though

it wasn't its fault that it didn't generate enough juice to power the robot. Then I scooped up the lemon, wiped up its juice with my sleeve, and tossed it into the trash. Phoenix's mouth dropped open. "Kate, why did you do that?" She pointed to the wastebasket. Then she took the lemon out again and added it to her composting project. At least the lemon would get to be part of STEM Night one way or another. "Don't give up, Kate," said Ms. Daly from the next table, where she was helping Rory with his cloud experiment. "I won't," I said, even though I wasn't feeling super excited about powering up a calculator. I thought about real scientists. Real scientists did not give up. They did not squash lemons. It took Thomas Edison over a thousand tries to invent the light bulb. So I refused to be droopy about all of this. "It's okay, I have a bag of fresh lemons in the back. I'll get another one." With the calculator in my hand, I raced to the side counter next to the sink where I had stored a bag of extra lemons. Only I didn't see the bag, so I checked the glass cabinet above. No bag. I checked again. I opened some drawers. Not there either. My