When St. Christopher School fourth-grade teacher Gabrielle Olivo spoke to her class recently about San Jose’s punishing flood, she asked them to imagine the victims who had lost their belongings and places to live.

Her message resonated particularly with one of her students, 10-year-old Nick Rubino, an athletic youngster who likes to play football, basketball and baseball. In that order.

Later that day, a Friday three days after the flood, an idea came to Nick, who wanted to contribute to the school’s relief fund for the Silicon Valley Red Cross.

His house in Willow Glen had two healthy Meyer lemon trees in the backyard. The lemons were ripe. What if he picked them and made lemonade to raise money for the victims?

“I always wanted to do a lemonade stand,’’ he told me. “And the fundraiser was going on during that time. So my mom agreed with me and said we could do it.’’

As it happened, they had a convenient spot for the stand. The next day, a Saturday, Nick’s basketball team, the Razorbacks, was playing in the Upward league at Cathedral of Faith.

With the permission of the Cathedral of Faith folks, who understood the unusual circumstances, Nick planned to run his stand from a spot outside the basketball gym.

So on that Friday night, with the help of his parents, Nick squeezed more than 50 lemons and combined them with a simple sugar-based syrup to make lemonade. He also made a large sign that said, “San Jose Flood Fundraiser. Lemonade $1.’’

The next day, almost four hours before his game was to start, Nick and his younger brother, Giovanni, set up shop outside the gym, trying to corral passersby into contributions.

The end of February isn’t a time when people naturally yearn for lemonade. So Nick persuaded people to give $1 for his fund even if they weren’t sampling the drink.

But he says the lemonade wasn’t bad at all. “A lot of people said it was good,’’ he told me. “We didn’t get a bad review on it.’’

By the time his game rolled around at 2 p.m., Nick and Giovanni had collected close to $300.

Nick asked his father whether he could stay with the stand until the second half. But as the biggest player on the team — he is 4-foot-8, and growing — Nick was needed in his place under the basket.

So with reluctance, they closed down the stand, collected their stuff, and put it in the car. After he got home, Nick went door-to-door asking for donations. He collected $92 more.

A lot of San Jose people have given enormous amounts of time and money to help the victims of this flood. St. Christopher School raised $5,500. And just the other day, a Los Angeles businessman, Kieu Hoang, gave $5 million for flood relief.

But for a 10-year-old, raising nearly $400 was no small feat. It’s made his family proud. People are fond of saying things like “It’s about the next generation.’’ With Nick Rubino, you can drop the word “next.’’ He and his brother have had impact now.