by Mark Kelly
“That one made sense to me,” Scott said, “because I happen to know from personal observation that our dad lazing around on the sofa will stay lazing around on the sofa until a powerful force—like our mom—makes him get up.”
“There’s another part of the first law too,” Mark said. “Once something’s moving, it stays moving, unless a force slows it down.”
“Yeah, and that part didn’t make sense to me,” said Scott, “because I also happen to know that if I throw a baseball and no one catches it, it doesn’t fly forever. It would be cool if it did, though.”
“Actually, it would be kind of dangerous,” said Barry. “Everybody’d always be getting hit with escaped baseballs, footballs, Frisbees, old javelins from King Arthur’s time . . .”
Egg and Howard started to explain at the same time why flying javelins aren’t much of a threat, but Scott stopped them. “Slow down a sec, would you? I already feel stupid.”
“You’re not stupid. It was a good question,” Egg said.
“Oh, come on,” said Mark. “He’s at least a little bit stupid.”
“Scott doesn’t seem that stupid to me,” said Howard.
“Thanks . . . I think,” Scott said. Then he looked at his brother. “If you know so much, you explain it.”
“Uhhh . . . ,” said Mark.
“Thought so,” said Scott.
Egg tried again. “There are two forces that stop the baseball, but they’re both so familiar that they’re easy to forget—gravity and friction.”
“Okay, I get gravity,” said Scott. “We already covered it, plus it’s the reason a high fly ball doesn’t go to Jupiter. But friction means rubbing against something. What’s the baseball rubbing against?”
“The air,” Egg explained. “Think of air like water, because in a lot of ways it is. If you threw a baseball in water, the water would resist, and the baseball wouldn’t get far. Air is the same thing only not as dense, so it doesn’t slow things down as much.”
Scott nodded. “Okay. I think I am now officially ready for the second law.”
Mark opened his mouth, but Howard was faster. “Force equals mass times acceleration, which can also be expressed as the equation F=ma.”
Barry nodded.
Everybody else just looked at Howard, who finally shrugged. “There’s nothing else to explain. That’s it.”
“Maybe for you,” Mark said. Then he looked at Barry. “You want to try that in regular human-speak?”
Barry said, “Going back to throwing a baseball, the force is how hard your arm pushes it, the mass is the ball, and the acceleration is, well . . . acceleration.”
“The rate at which the ball’s speed speeds up,” Egg said.
Howard added, “Another way to say that is, the rate of change of its momentum.”
Mark had had just about enough of Howard showing off how smart he was. The kid was weird. Why didn’t he ever smile? How come Egg had even brought him?
Scott closed his eyes and tugged his short hair. “You’re all giving me a headache. But I think it makes sense. How hard you throw the baseball, and the mass of the baseball, determines how fast the baseball accelerates.”
“Mass is the same as size, right?” Mark said.
“Sort of,” Barry said. “Mostly when we say size, we think of volume. So the volume of a beach ball is bigger than the volume of a baseball, but a baseball is more massive—”
“—because it’s heavier,” said Mark. “I get it.”
Egg shook her head. “Not exactly. Mass is more like the amount of stuff in stuff. Remember that the idea of ‘heavy’ relates to gravity, and in space gravity’s force is less than on Earth. So the weight of something changes when it’s in space, or on the Moon, or on Earth, but its mass is always the same.”
“There’s an equation that describes mass,” said Barry.
“I was afraid of that,” said Scott.
“Mass equals density times volume—M=D·V,” Barry said.
“What Scott said about common sense is right,” Egg said. “But you have to remember there are other influences on acceleration besides force and mass. There are also friction and gravity.”
“Friction and gravity again?” said Mark.
“And because the second law is an equation, you can work it backward and sideways,” said Barry.
“Try that one again,” said Scott.
“If you know the mass of something and how fast it’s accelerating, you can figure out how much force it took to move it. And if you know its acceleration and the amount of force that moved it, you can figure out its mass.”
Scott nodded. “That’s cool.”
Barry said, “That’s algebra.”
“Really?” Scott said. “So now I know algebra?”
“Algebra just means using variables—like letters—to solve problems. So if I say two x equals six, solve for x, then I’ve expressed an arithmetic problem as algebra,” Barry said.
“X equals three,” Mark said.
“My brother, the genius,” Scott said.
Mark waved and bowed to an imaginary crowd of fans—“Thank you, thank you very much”—until Howard interrupted by saying, “I don’t think Mark is a genius.”
Mark was more surprised than insulted, but Scott and Barry both sat up, ready to pound the kid.
“Howard!” Egg said. “That was a joke!”
Howard looked from Scott to Barry, alarmed by their reaction. “It was?”
“Sometimes Howard doesn’t get jokes,” Egg explained.
“He got the one about Fig Newton,” Mark said.
Keeping his eyes on Scott and Barry, Howard shook his head. “No, I didn’t. I just laughed because everyone else did. A Fig Newton is a cookie, right? What does a cookie have to do with Sir Isaac Newton?”
“They have the same name,” Barry said.
Howard nodded solemnly. “Yes.”
Mark saw that the kid was genuinely confused. He’s weird, all right, Mark thought. And kind of obnoxious, but maybe not on purpose. Then Mark thought of somebody on a TV show his parents used to watch, Star Trek. The character’s name was Mr. Spock, and he never smiled. Howard reminded Mark of Mr. Spock.
Thinking of that, Mark felt less angry. “What’s really insulting,” he said, “is how you guys think the perfectly reasonable idea that I’m a genius is only a joke.”
That made everybody laugh—Howard too. But Howard’s laughter seemed nervous.
CHAPTER 13
* * *
“Remember how my butt was starting to hurt?” Barry said. “Well, it’s happening again, not to mention I’m getting sweaty.”
“Luckily, there’s only one more law,” said Egg. “For every action, there is an equal and opposite reaction.”
Mark nodded. “So if I bounce a basketball on the ground, it bounces back up. I get it. Are we done?”
Egg frowned. “A basketball isn’t a good example. There’s gravity, friction, the effect of the compression of the air inside, the rubberized material . . .”
“Yeah,” Scott said, “because in my personal experience, if you try to bounce a rock off the ground, it won’t work. I think maybe Newton got the third law wrong.” He shrugged. “But hey, he made a good effort. And two out of three isn’t bad.”
“It’s not good enough to qualify you as a genius, though,” Mark said, “and genius is something I happen to know about.”
Howard pointed at Mark. “That was a joke. Wasn’t it?”
Mark said, “There’s hope for you yet, but can I ask a question? What are you doing here, anyway?”
Scott and Barry fidgeted.
Egg frowned angrily. “He’s here because I invited him!”
“I know that,” Mark said, “and I also know you invited him for a reason, so what was the reason?”
Howard did not seem bothered by the question. “My Altair 8800,” he said. “Also, I know BASIC.”
Scott looked at everybody else. “Translation?”
Egg explained. “An Altair 8800 is a computer that’s small enough so you can have one at your house—and Howard does. BASIC is the name of a language for telling the computer what to do.”
“Whoa,” said Barry. “That is so cool. Did you put the 8800 together yourself or buy it preassembled?”
“I put it together,” Howard said. “It wasn’t hard.”
Now Scott and Mark were paying attention. This Howard kid had assembled a real computer himself! That was way better than taking apart a calculator. They had a thousand questions, but before they could ask even one, Egg looked up and waved.
“My mom’s here,” she said. “We gotta go.”
CHAPTER 14
* * *
Howard lived west of town, so Mrs. O’Malley gave him a ride to his dad’s work, which was nearby on the highway at an auto repair place called Nando’s.
“See you tomorrow at two?” Howard said to Egg when he opened the car door.
“Sounds good,” said Egg. At the same time, a girl came out of Nando’s office door and smiled and waved.
“Hang on a sec, Mom, could you?” Egg jumped out behind Howard and jogged over to talk to the girl.
“That’s Lisa Perez,” Mrs. O’Malley told Mark, Scott, and Barry. “She’s in Howard’s class at school, and it’s her dad’s shop.”
Egg came back a few seconds later and climbed in. Howard turned to wave, but didn’t smile.
“He doesn’t like us,” Scott said as they drove off toward Grandpa Kelly’s house. “And now we’ll never get to fool around with his computer.”
“I don’t think it’s that,” Egg said. “He’s just not a smiler.”
“So, Egg, what is it you and your good friend Howard are doing tomorrow at two o’clock?” Mark asked.
“Library,” Egg said, “just like you.”
“Hey—wait a second,” Mark said.
“You’ve got to be kidding!” Scott said. “Today was enough library to last me through summer, and possibly high school.”
“Seriously?” said Egg. “You thought that was all the research we needed to do to build a—”
“Egg!” Mark waved to keep her from giving away the secret.
“—a science fair project,” Egg concluded.
“You guys have to admit there’s a lot we don’t know yet,” Barry said.
“Yeah,” said Egg. “Like we should research the history of the space—”
“Egg!” Mark interrupted again.
Mrs. O’Malley laughed. “What if I just promise not to listen?”
Egg said, “Or what if everybody just agrees we’ll go to the library again tomorrow? We can talk then.”
Barry was in favor. Scott and Mark grumbled, but in the end said okay.
When Mrs. O’Malley pulled into Grandpa’s driveway, she said, “I trust you kids, so I’m glad to support the project you’re working on. It’s even okay—for now—if you don’t want to give away secrets. However, I’d appreciate it if you promised me one thing.”
“What’s that, Mom?” Egg asked.
“Just please don’t blow anything up.”
* * *
“I wonder why everybody’s so worried we’ll blow something up,” Mark said later. The three boys were clearing dinner dishes. Grandpa had grilled hot dogs, and they had eaten outside at a table on the flat patch of dirt that was supposed to become a patio one day. Now the boys were cleaning, and Grandpa was talking to someone—they didn’t know who—on the telephone extension in his bedroom.
“I guess we just look dangerous,” said Scott.
“Or”—Barry stuck out his tongue, rolled back his eyes, and waggled his fingers—“crrrrr-azy!”
In the kitchen, Scott turned on the water to start washing dishes. “Maybe they’ve figured out what the project is. It’s kind of like blowing something up. There will be flammable fuel, and we’ll ignite it to send the rocket into space.”
“That’s what Newton’s Third Law is about, isn’t it?” Mark asked.
Scott turned off the water; then both twins looked at Barry.
“Oh, I get it,” Barry said. “With Egg and Howard gone, now I’m the resident brain.”
Mark was quick to reassure him. “We think you’re brainy even when Egg and Howard are around.”
“Just not that brainy,” said Scott.
“On the other hand,” said Mark, “you do have two good qualities. First, you get jokes, and second, you’re not a girl.”
“Another thing I get is Newton’s Third Law,” said Barry, “which is key to understanding how rockets work.”
Mark tossed him a dish towel. “You can explain while you dry the dishes.”
“More chores.” Barry sighed. “Hasn’t your grandfather ever heard of this radical new invention, the dishwasher?”
“He says he doesn’t need one for just one person, and if it’s more than one person, it’s us, and we’re the dishwashers.” Mark handed Barry a plate dripping with water.
Barry talked while he dried. “Rockets were actually invented by the Chinese hundreds of years ago, then improved on by the Indians—the East Indians, I mean—and the British.”
Putting dishes away, Mark threw back his head and sang: “O-oh, say can you see-e-e, by the dawn’s early light, what so proudly we hailed—”
Scott slapped his ears with his sudsy hands. “Make him stop!”
Barry laughed. “Yup, ‘the rockets’ red glare’ in ‘The Star-Spangled Banner’ refers to British weapons fired in the War of 1812. Rockets were originally weapons and fireworks. The first guys to think of using them for space travel were science fiction writers like H. G. Wells and Jules Verne.”
“Oh, sure—like I believe writers thought of that before scientists,” Mark said. “You’re just saying it because you like that science fiction stuff.”
Scott turned the water off and pulled the stopper out of the sink. “I don’t see why those writers thought a rocket would work best for going into space. Why not a giant slingshot powered by a giant rubber band? The astronaut climbs into a harness and vrroooom!—he’s off in space.”
“Except,” Barry said, “accelerating to top speed instantly flattens his bones, not to mention all his organs, and”—Barry ran a finger over his throat—“no more astronaut.”
“How about a giant ladder?” Mark asked.
“It wouldn’t put you in orbit, for one thing,” said Barry. “And besides, any ladder that tall would collapse under its own weight.”
“I guess we’re stuck with a rocket,” said Scott.
“That’s the best anybody’s figured out so far, anyway,” said Barry. “A rocket doesn’t need atmosphere. It’s a reaction engine, which means it works on the basis of Newton’s Third Law—action–reaction. Action: the exhaust being pushed out by burning fuel. Reaction: the rocket going in the opposite direction.”
Mark said, “And when you’re blasting off, that direction is supposed to be up.”
“Ye-a-a-ah, but only at the beginning,” said Barry. “Once you get to the right altitude, you pitch over and the velocity shifts to horizontal so you can fly parallel to Earth’s surface—in other words, you’re put in a stable orbit. Galileo and Newton both devised equations describing the necessary velocity for orbiting a body or for escaping its gravitational pull—like if you want to go to the moon or Mars.”
“Mars!” said Scott. “Hey, that’s a great idea!”
Mark was equally enthusiastic.
But Barry waved the dish towel like a flag of surrender. “How about we stick to one thing at a time?”
CHAPTER 15
* * *
Since Grandpa didn’t have a TV, the twins had to miss Emergency!, Mark’s favorite show, that night. Instead, they lost to Grandpa at gin rummy while listening to the Yankees beat the Tigers on the radio. The next morning, they got dressed to go swimming after breakfast.
“What? No chores?” Barry said as they headed down the path to the water. “I thought we’d at least
have to build a barn or clear a few acres of brush.”
“That’s later,” Mark said.
“After we go to the library and improve our minds,” said Scott.
“Hey”—Mark slapped Barry’s shoulder—“we told you it’d be fun if you came with us to Greenwood Lake. Aren’t you glad you’re here?”
Barry grinned. “Sure. No matter how many chores we have to do, it’s good not to be listening to my dad nagging my brother, and my mom nagging my dad for nagging my brother.”
“Is it like that all the time?” Scott asked.
“Enough of the time,” Barry said. “My dad was a pilot in Korea. He came back, went to work, then went to college at night on the GI Bill, which pays for school for veterans. He doesn’t see why it should be any different now, but Joe says it is. I don’t know who’s right, so I stay clear of them when the subject comes up.”
The path to the beach went by Grandpa’s workshop, then through a patch of trees past a field that had been cleared for houses, and then through a mess of low-lying shrubs before going over a rise and arriving at a quiet beach. Mark sprinted for the water: “Last one in’s a rotten egg!”
The boys swam for a while, then took Grandpa’s rowboat out.
“Look—Newton’s laws in action,” Scott said as he used the oars to push the boat through the water.
“If it weren’t for friction, you’d only have to row one time, and then we’d just keep going forever,” Mark said.
“Sounds relaxing,” said Scott.
“Doesn’t gravity come into it, too?” Mark asked. “Why aren’t we sinking?”
“Newton’s Third Law,” said Barry. “Action: The force of gravity pulls the boat down. Reaction: The water pushes it up.”
“What keeps it from tipping over?” Mark asked.
“The center of gravity is in line with the center of buoyancy,” Barry said.
“Boy-ancy! You mean as opposed to girl-ancy, right? Good thing we didn’t invite Egg to come with us, or we’d sink,” said Mark.
“I don’t think that’s what he meant,” said Scott.
