A Midsummer's Equation

FIFTEEN

With a whoosh of compressed water, the rocket soared into the distance. Kyohei frowned. He’d missed the moment of launch again. The rocket was flying across the water too fast for his eyes to follow, with much more power than he’d expected.

Yukawa held up a small pair of binoculars and watched as the rocket splashed into the ocean.

“Distance?”

Kyohei checked the reading on the electric fishing reel they had stuck into the ground. They had attached a fishing line to the back of the rocket, and Kyohei was in charge of checking the distance of each launch.

“Uh, 135 meters. A little less than last time.”

“Right. Reel her in,” Yukawa said. He was sitting cross-legged on the breakwater and typing on his laptop, using his satchel in place of a desk.

Kyohei watched him out of the corner of his eye as he reeled the rocket back in. This was the seventh time in a row they’d performed this exact same procedure. Yukawa clearly loved firing off the rocket, but he hadn’t done anything about showing Kyohei the bottom of the sea yet. Kyohei was starting to wonder what the point of all this was.

Yukawa squinted at the screen of his laptop and folded his arms across his chest. “I think we have the results we need. I’ve determined the source of the variation between our simulated results and the actual launches. We should be able to achieve perfect conditions for our launch.”

“You mean we have to shoot the thing off again? How many times are we going to do this?”

“As many times as possible,” the physicist answered. “With water rockets and manned rockets alike, it behooves us to test our equipment as many times as possible. In the case of an actual rocket, however, there are budgetary constraints that prevent unlimited testing. In our case, the main constraint is time: the sun is starting to get pretty high in the sky, and if we don’t hop to it, we’re going to miss our chance to see these so-called ‘crystals’ on the seafloor. So, the next launch is for real.”

Yukawa stood and tossed the plastic bucket into the water. The bucket had a line of nylon rope tied to the handle.

While Kyohei continued reeling in the rocket, Yukawa deftly manipulated the bucket at the end of the rope, scooping up seawater as he had done six times previously.

Yukawa’s rocket was remarkable not only because of its size, but also the curious shape of its fins. Yukawa claimed they were his own original creation, but Kyohei couldn’t see what was particularly creative about them. Another unusual feature of the rocket was a weight he placed inside, about the size of a pack of cigarettes. He would adjust the position of the weight very slightly each launch. The weight measured in at almost one hundred grams, which Kyohei thought had to be cutting their distance by a lot, but according to Yukawa, the weight was a vital component.

Not for the first time, Kyohei wondered who exactly his strange professorial friend was. Yes, Kyohei had expressed some interest in seeing the crystals that gave Hari Cove its name, but it wasn’t like he’d asked anyone to go to such lengths. Lengths he didn’t even understand, because Yukawa wouldn’t explain anything to him. All he could do was watch in silence as they performed one test launch after another.

Not that he was upset. To the contrary, it was exciting. He had the sense they were doing something important, even if he didn’t know what that was.

“Ready for the real thing?” Yukawa asked, reaching into the rocket and pulling out the weight he had carefully placed inside.

“Huh, you’re taking it out?” Kyohei grunted. “I thought that was vital?”

“It was vital, but it was just a stand-in for testing purposes. We’ll be using something else for the actual launch.”

Just then, a cell phone rang. Yukawa reached into his satchel, pulled out his phone, and checked the display. A cloud came over his face as he answered. “Yukawa speaking.”

The person on the other end was saying something Kyohei couldn’t hear. He watched Yukawa’s eyebrows move.

“Sorry, but I can’t make it today,” Yukawa said. “Anytime after tomorrow would be fine. Yes, I’m in the middle of an experiment. Good-bye.” He hung up.

“Work?” Kyohei asked.

“It was DESMEC, telling me to come to a meeting,” the physicist explained. “That is, they call it a meeting, but all they really do is eat and waste my time. That hardly qualifies as work.”

Yukawa began pouring a carefully measured amount of seawater into the rocket tank through a modified water valve at the rocket’s base. After setting the rocket on a homemade launch pad, he attached a bicycle pump and began filling the tank with air. Kyohei could see the bottle expand. They knew from the previous testing exactly how much seawater to use, how much air to pump, and what angle to set the launch pad. The only difference this time was that the testing weight was gone.

“There,” Yukawa said, removing the pump from the rocket. He pulled his cell phone back out and punched at it with his thumb before putting it into the small chamber where the test weight had sat.

“What? You put your cell phone in there?”

Just then, Kyohei’s own phone began to ring. He fished it out of his pocket.

“Answer that after the launch,” Yukawa said. “Now, on the count of three. Three, two, one, liftoff!”

Yukawa pressed the switch attached to the launch pad and the rocket took off, blasting water behind it with impressive force. Kyohei’s eyes darted forward, following the semitranslucent rocket as it caught the sun and glimmered against a backdrop of blue sky.

The rocket landed in the sea a considerable distance further than their previous launch. Kyohei checked the reading on the fishing line. “Wow, 225 meters! A new record!” he shouted in excitement.

“Good,” the physicist said calmly. “Now answer your phone.”

Only then did Kyohei realize that his phone was still ringing. He fished it out of his pocket and noticed the incoming call was a video call. He pressed the button to accept and stared at the screen.

“Hey!” On his screen he could see a glimmering undersea world of reds, blues, and greens. The seafloor looked like a massive stained-glass window. The water was perfectly clear, and light from the sun above refracted in a hundred different angles, each creating a different color.

“Well?” Yukawa asked.

Kyohei showed him the phone screen. The faintest hint of a smile came to the physicist’s face. He gave a satisfied nod. “I’d say our experiment was a success.”