Nate told Junie to turn on Uncle Harold’s projector that they’d positioned so the light would shine right in.

“This is going to be so great,” Junie said in a low, husky voice.

“Don’t get your hopes up yet, J,” Nate told her. “It might not work.”

“You got to think positive, you guys.”

“I’m just being realistic. Things are always a lot more likely to go wrong than right.”

In a few minutes the gases began to swirl as the atmosphere inside the chamber cooled. “Light, Junie,” Nate said to her. She shot the beam into the cloud chamber.

“This is when we’re supposed to see the ionizing radiation from the watch,” Nate said.

Five minutes passed. Nothing. Two more, and still no sign of radioactive particles shooting across. Nate took out their troubleshooting list.

“It says to be on the lookout for air leaks,” he read. “Also, there could be a problem with the size of our box. It might be too short or too tall.”

Then it started: first just one small streak, then more tiny, spidery tracks of light. Sharp, sputtering flashes zapped through the swirling mist along the base of the chamber. What they had caused to take place seemed like magic, except Nate knew it wasn’t magic at all; it was science.

“It’s so beautiful, Nate,” Junie cried as the mist from the ethyl alcohol gradually evaporated and the rays ceased to be visible.

“I can’t believe it actually worked,” Naomi added. “I kept thinking a couple of kids would never be able to pull off something this amazing.”

“But we haven’t reached our goal yet,” Nate reminded her. “So far, all we’ve actually seen is evidence of radiation from Poppa’s watch face. The real magic comes if we can spot radiation from star particles.”

He lifted the top from the cloud chamber and removed the watch face. Then he dripped more ethyl alcohol on the blotting paper and replaced the lid again. He set the cloud chamber back on the dry ice to cool a second time.

“Now we wait to see the real thing,” he said. “Evidence of actual radiation from activity in space.”

Once again, the chamber gradually filled with vapors. Junie shone the projector beam inside. They waited. Ten minutes. Fifteen.

“I don’t know what the problem is,” Nate said. “But we can’t leave our dry ice out any longer or it’ll melt too much, and we won’t have enough for later.”

“I bet we just need to leave it longer,” Naomi said as he placed the dry ice back in the cooler. “When we do it at the science fair, we’ll give it lots more time. And anyway, we’ve got the rays from the watch as our backup. No matter what, that’s pretty impressive.”