6. Glue another bottle cap onto one end of the last skewer, then slip the skewer through the straw at the narrow end of the frame. Trim the skewer’s free end so that it is just long enough to hold another bottle cap. Slip on the bottle cap and glue in place.
CONNECT THE WIRING
7. Line up 2 diodes with the stripes on the ends facing each other. Twist together the wires on the facing ends.
8. Connect the third diode to the first two as shown, with one wire twisted onto each of the free wires of diodes 1 and 2.
9. Attach the battery pack. Twist the red wire from the battery pack to the wire coming from the right end of the diodes (the end with the stripe on the upper diode). Attach the black wire from the battery pack to the motor.
10. Attach the solar panel. Twist the red wire from the solar panel to the wire coming from the left side of the diodes. Twist the black wire from the solar panel to the motor, on the same end where the battery pack is attached.
11. Attach the diodes. Use a length of extra wire to connect the free end of the motor to the connection between the two lower diodes. With batteries in the battery pack, the motor should spin. Remove the batteries, or disconnect one of the wires, to stop the motor.
MAKE THE PROPELLER
12. Copy the fan pattern here onto a piece of paper. Then trace it onto the deli container lid and cut it out. Bend the blades as shown. The sides of the blades should be bent up and down in an alternating pattern: one up, the next one down, and so on.
13. Poke a hole in the center of the fan and slip it onto the shaft of the motor. Make sure it turns freely, and then glue it in place.
THE FINAL STEPS
1. Glue the motor onto the wide end of the cardboard frame. Make sure the fan turns freely before you glue it.
2. Glue a piece of cardboard across the middle of the frame, then glue the battery pack on top of that. Finally, glue the solar panel on top of the battery pack, tilted up and facing forward.
3. Add batteries to get the car rolling. The solar panel will recharge the batteries between rides. You can also run the car with the panel detached to get more speed (there will be less weight; just wire the battery directly to the motor). Experiment with bigger fans for more wind power! You can disconnect the batteries to see how the car moves on solar power alone. Can you find ways to make the car lighter so that it goes faster on solar energy?
Nick and Tesla worked on the solar-powered rover for the next hour, trying out different combinations of sticks, wires, improvised wheels, and a miniature driver that Silas insisted they include (which they threw away as soon as his back was turned). Their only break came when their lookout by the door—DeMarco—reported hearing footsteps in the hall. Nick and Tesla quickly hid the tools while their lookout by the window—Silas—scrambled over to position in front of the half-finished rover.
The kids listened as someone unlocked the door. Seconds later, Ethel and Gladys entered carrying ratty old sofa cushions and a bag of tortilla chips.
“Here’s your bedding,” one of them said as she dumped the cushions on the floor.
“And here’s your dinner,” the other one said, tossing the chips to Silas.
“Thanks,” said Silas. “Got any salsa?”
“Or some carrots?” DeMarco asked loudly, drawing the old ladies’ attention his way. “Not everyone’s into junk food, you know.”
Ethel and Gladys ignored their requests and stalked out of the room, locking the door behind them.
“Oh, well,” Silas said as he tore open the bag of chips. “Fortunately, some of us are into junk food.”
Nick and Tesla got right back to work.
Two hours later, they were done. Or so they hoped. The solar panels and batteries were feeding power to the rover’s wheels, but it was barely enough to generate movement.
“I’d like to be rescued sometime this year, if possible,” DeMarco said as he watched the rover inch across the floor with all the speed of a sleepwalking tortoise. “That thing’s not gonna reach the highway for at least a decade.”
“What’s with the batteries?” Silas asked. “I thought this thing ran on sun power.”
“Lots of solar power systems use batteries,” Nick explained, “so that the energy collected from the sun can be stored and used when there’s no sunlight.”
“These batteries are rechargeable but weren’t juiced up,” Tesla said. She pointed up at the flickering old fluorescent lights hanging overhead. “And those things aren’t bright enough to recharge them quickly. But when the sun comes out tomorrow morning, the batteries will charge and the rover will really get going.”
“You sure about that?” DeMarco asked.
The rover, now in the shadow cast by one of the desks, was moving even more slowly than before. It was going about as fast as a sleepwalking tortoise with a sprained ankle.
“We’re sure,” said Nick somewhat unconvincingly. He was trying to be upbeat, but it didn’t sound like he believed it. “Coast still clear?” he asked Silas, who was back at his post, standing on a desk so he could see out the window.
Silas shrugged. “I think so. Then again, it’s so dark out, I can barely see two feet in front of my face.”
“Very comforting,” Nick muttered.
“Yes,” Tesla said firmly. “It is.”
Nick sighed and then nodded. This “being positive” stuff was harder than he thought. But he understood Tesla’s point. For what they planned next, the darker the better.
“All right,” Nick said. “Let’s see who the lucky one is.”
He held out a fist. Tesla and DeMarco followed suit.
“One,” said Nick, pumping his fist up and down. The others did likewise. “Two. Three.”
Two of the hands stayed balled into fists. The third flattened out, palm down.
Two rocks, one paper.
Two losers, one winner.
“Dang,” said DeMarco.
“Darn,” said Tesla.
“Woo-hoo,” said Nick—the one who’d chosen paper—unenthusiastically.
“Best two out of three?” DeMarco suggested.
Nick shook his head and bent down to pick up the rover.
They’d only been able to get a window open far enough for someone small—that is, anyone but Silas—to slip through. Nick had just won the honor. Now it would be his job to take the rover out to the road and position it to drive away once the rising sun began to power it.
Nick climbed onto a desk and stared at the open window, unsure of the best way to get out. After a moment or two, he decided that headfirst made the most sense. He bent over and started trying to snake his way through the opening.
“Let me help,” Silas said behind him.
Nick was about to tell him not to bother—“Let me help” were ominous words coming from Silas—but before he could speak, he felt hands grasp his ankles and jerk his feet off the floor.
“Whoa, whoa, whoa!” Nick cried as he shot outside. He ended up in a heap on the cool, hard pavement by the side of the building.
“Geez, guys,” he heard Tesla say. “Ever hear of being sneaky?”
Nick wanted to zing his sister with a snappy comeback, but he couldn’t think of one. Getting shoved through an open window can rattle a guy.
He stood and dusted himself off, then stepped back to the window. Tesla was waiting with the rover, which she carefully maneuvered past the glass and into Nick’s waiting hands.
“Julie or the old ladies could come back any second to check on us,” Tesla said. “Don’t take any longer than you have to.”
“That was my plan, Tez,” Nick said.
“And be careful,” Tesla added.
“That was my plan, too.” Nick turned and walked away.
Tesla stuck her head out the window to watch him go. It was no use, though. The night was utterly dark, and after only a few steps he disappeared into blackness.
Nick knew he was walking along the side of the building—he could see it as a ghostly gray blob to his left—b
ut he couldn’t make out any other part of the abandoned base. He looked up, searching the sky for the moon. It wasn’t there. Still, he stopped to stare in wonderment at what he did see.
Ablaze above him were countless stars, the core of the Milky Way cutting across them in a long, cloudy, diagonal ripple. It was the most beautiful, brilliant nighttime sky Nick had ever seen.
Nick could feel a chilly wind blowing over the desert. The paper they had taped to the side of the solar rover fluttered in the breeze.
Written on the paper was this:
Most of the note had been written by Tesla, because the boys assumed she’d have the best handwriting. (“That’s sexist,” Tesla had complained at first. She stopped arguing after the guys showed her what their penmanship looked like.)
The “Sorry—we don’t know her first name” part had been added by Nick, who was worried the note wasn’t specific enough.
The “The fate of the free world may depend on it!” part had been added by DeMarco, who was worried the note wasn’t dramatic enough.
Silas wanted to add illustrations, because he was worried the note wasn’t visual enough, but the others told him that was unnecessary. (They also knew that a condor would end up in the drawings, and that would just confuse people.)
Nick nervously ran a thumb over the tape fastening the note to the rover. It would have to hold as the little makeshift car rolled its way over dozens of miles of dusty road. If it didn’t, the note—and their only hope of rescue—would drop off and flutter away into the sun-baked desert bleakness. Never to be seen again.
Like them, perhaps.
The muddled gray blob beside Nick—the wall he’d been walking beside—suddenly disappeared. He’d reached the end of the building and kept walking without even realizing it. He was out in the open now. And the moonlight, faint as it was, made Nick feel like he was standing in a spotlight.
Nick quickly backed up until he was hidden again by the building. Then slowly, cautiously, he peeped around the corner. A crescent moon hung low in the sky. It gave just enough light to create recognizable silhouettes. Nick could make out more buildings, a hangar, the truck that had brought them all there.
But no people. At least not out in the open. If anyone was around, they were sticking to the shadows.
Nick did the same as he eased around the building and began creeping toward the long, unwinding road that stretched off to the horizon on the other side of the truck. Eventually, he again had to step out into the open and leave the building—and the cover it provided—behind.
Once he was in the moonlight, plainly visible to anyone who might happen to look his way, Nick wasn’t sure which was the better option: Should he move slowly but quietly? Or fast but not so quietly?
Nick opted for slow but quiet. His decision wasn’t made so much because he didn’t want anyone to hear him. He just couldn’t stand the thought that someone else might be out there, someone he couldn’t hear. So Nick took steady, near-silent steps until he reached the road, his eyes scanning the black void on either side of him, his ears straining to pick up the slightest sign that he wasn’t alone. Then he walked along the roadside with no specific destination in mind beyond far enough. He couldn’t take the chance that Bob or one of his flunkies would spot the rover in the morning. Nick had to give their vehicle as big a head start as possible.
This will do, one part of Nick’s psyche said after he’d been walking along the road for a minute or two.
No, it won’t, said another, braver part.
Nick continued walking for about another minute. Then he froze.
A soft, swishing sound raised goosebumps on the back of his neck. The noise wasn’t coming from behind him, from the base. It was off to his right somewhere.
It was coming from the desert!
Nick heard it again. A sort of shushing. Sh-sh-sh-sh-sh …
He realized it was the sound of light, fast footsteps in sand. And they were coming closer.
Told you! said the first part of Nick.
Shut up, said the second.
Will you just put down the darned car and run away already? said a third.
“Good idea,” Nick muttered to himself. He squatted and carefully positioned the rover so that it was perfectly straight on the road, as straight as he could orient it in the faint moonlight. Then he stood up, spun around, and started running.
Had the shushing footsteps stopped? Nick couldn’t hear anything except for his own panting and his footsteps slapping hard on the pavement. He thought he saw something out of the corner of his eye but couldn’t be sure.
Low, shifting shadows by the side of the road … no, by the sides of the road. They were on both sides of him. Whoever or whatever “they” were.
Nick started running faster—faster than he had ever run in his life. But it wasn’t fast enough.
The shapes stayed with him, ever so close behind. However, the sound they made changed. Instead of sh-sh-sh-sh, Nick now heard clack-clack-clack-clack. Nick was certain he was hearing claws running on blacktop. The things from the desert—the shadows—were on the road with him. And they were closing in fast!
Nick opened his mouth not knowing if he was about to shout for help or scream bloody murder.
It didn’t matter. All he managed to say was “Oof!” He’d run straight into something else in the dark—something that crashed to the asphalt with him and said “Oof!” too.
“Go! Get out of here, you mutts!” a familiar voice shouted nearby. “I might look small, but I’m tough!”
“DeMarco?” said Nick. He blinked at the person he’d just accidentally tackled. “Tez?”
“I don’t think we want to be lying on the ground just now, Nick,” Tesla said.
“Oh. Right!”
Nick hopped up, and his sister did the same. They turned to find DeMarco stamping his feet and waving his arms at two snarling, glowering, doglike animals.
They weren’t dogs, though. They were either small wolves or large coyotes.
Nick and Tesla started stamping their feet and waving their arms, too.
With a lip-curling snap, one of the animals wheeled around and skulked away into the desert. The other watched the kids for another moment, then slowly turned and casually trotted off up the road. Nick could still hear the clack-clack-clack of its claws long after it was gone from sight.
Nick let out a sigh of relief. “Thanks, guys. How did you know those things were out here?”
“We didn’t,” said Tesla. “We just wanted to see what was taking you so long.”
“We’d better get back fast,” said DeMarco, peering toward the base. “It doesn’t look like anyone heard us, but the longer we’re gone, the greater the chance someone will notice.”
Nick didn’t argue. He disliked being a prisoner, but at that particular moment it sure beat walking around free in a coyote-filled desert.
As the kids hustled back onto the base, they heard a yipping cry in the darkness behind them. It was answered by another howl off to their left. Then another to the right.
No wonder Bob hadn’t bothered stationing Ethel or Gladys or Julie as guards outside. The desert was full of watchful eyes already. His captives weren’t going anywhere.
Until the sun came up, that is.
If they were lucky.
First it was discomfort that kept Nick awake. All the kids had to sleep on were the scruffy old sofa cushions Ethel (or Gladys) had given them, and they were so thin that it was impossible to get comfortable on the room’s cold, hard tile floor.
As the night wore on, then it was hunger and thirst that kept Nick awake. After divvying up the stale tortilla chips Gladys (or Ethel) had brought them for dinner, each of the kids received exactly seven and a half chips—and no water to wash them down.
Eventually, dawn came, and sunlight streamed through their room’s small window. But it wasn’t the harsh, unfiltered light of the desert morning that kept Nick from finally nodding off. Now it was worry.
&nb
sp; “Hey, Tez … you awake?” Nick whispered.
“I am now,” Tesla said.
“I was never asleep,” said Silas.
“Me, neither,” said DeMarco. “It’s been a long night.”
“I know what you mean,” said Nick. “How far do you think the rover’s gone by now, Tez?”
Tesla shrugged without opening her eyes. “I don’t know. Maybe a quarter of a mile.”
“That’s not far,” said Nick.
“Not far? It’s nothing,” said DeMarco.
“Patience, guys, patience,” said Tesla.
She rolled onto her side and began breathing deeply in a way that almost sounded like a snore. But Nick wasn’t fooled.
He finally gave up on sleep entirely and got up, walking over to the window. He stood there for a long, long time, one ear cocked to catch the sound of approaching sirens or helicopters or tanks or anything. But all he heard were the other kids either trying to sleep or pretending to.
Soon DeMarco got up and joined him. A minute later, Silas did the same.
“Hear anything?” Silas asked.
“No,” Nick and DeMarco said together.
“Patience, guys,” said Tesla through a huge yawn. “Patience.”
She reached over, picked up the cushion on which Nick had tossed and turned all night, and put it over her head.
“You’re not fooling anyone,” said Nick. “You’re as awake and as worried as we are.”
“Zzzzzzz,” came Tesla’s reply.
Of course, you can lie on the floor with a sofa cushion over your head for only so long, even when you’re trying to be the model of nonchalant calm. So eventually Tesla got up and joined the boys by the window.
She gazed up at the sky, then down at the shadows stretching out from the side of the building.
“It must be at least nine o’clock,” she said. “I bet the rover’s gone a mile by now.”
“How far does it need to go?” Silas asked.
Nick and Tesla's Solar-Powered Showdown Page 11
