scientists, stand up for your predictions! Let’s see which side you’re on!”

Each student stood up and spread out his or her arms, some tipping to the right, some tipping to the left, and some standing with their arms stretched straight out on either side.

Once they’d made their predictions, they sat back down. Mr. Figueroa said, “Who wants to start off?” He waited patiently as more and more hands went up. He finally picked Megan because he knew she would have something to say that would be likely to spark further discussion.

“I think it will go up, I mean the light-colored volleyball, the one you pumped, will go up,” said Megan.

“And why do you think that?”

“Because doesn’t air make things lighter? Like when you blow up a balloon with air, it gets light. It sort of floats.”

Several students began to talk at once. Mr. Figueroa reminded them that in order for everyone to hear, only one person could talk at a time. “Let’s use this volleyball as our talk ball,” he suggested. Mr. Figueroa’s class often used a talk ball during Circle Time. Only the person holding the ball was allowed to speak.

Mr. Figueroa handed the ball to Marisa.

“I’m pretty sure it will balance because air is nothing. I mean it’s invisible. It’s like nothing,” said Marisa. Several other students nodded and agreed.

Eduardo had his hand up and Mr. Figueroa called on him. Eduardo was born in Puerto Rico and had lived there most of his life. His English was improving, but he still mainly spoke Spanish and often struggled when speaking English aloud.

Más, more, um, more heavy? Tiene más air, más material,” Eduardo said.

”Let me see if I’ve got your idea right, Eduardo,” Mr. Figueroa said. “Are you saying you think the volleyball will be heavier, that it will go down on our pan balance, because it has more air, more matter, in it?” Eduardo nodded.

“Can you say a bit more about that?” Mr. Figueroa asked.

Eduardo spoke slowly and paused often to find the correct words. He had some difficulty with pronunciation, but the other students waited respectfully while he spoke, and some of the other Spanish-speaking students volunteered words or phrases when he seemed stuck.

“Once my papi had a flat tire and he use a pump like this. He pump the tire and his truck went up. The air make it to go up. The truck is heavy.”

“Wow! What an interesting observation,” Mr. Figueroa said. “Does anyone think they understood Eduardo’s observation well enough to put it into their own words? Can anyone repeat what Eduardo has told us?”

Keisha said, “I think I understand, because the same thing happened to me. I think Eduardo is talking about when his dad got a flat tire. And when they pumped the tire up, the whole car went up. It’s

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