Science Bowl contestants from Northview and Woodridge elementary schools in Prince George's County answer questions in the television studio. (Harrison Smith/The Washington Post)

Wearing a black suit and an orange tie that shines brightly under the television studio spotlights, Dave Zahren — commonly known as “Mister Z” — winds down Question Number 1, a medium-difficulty 15-pointer in the Zoo Parade category: “All mammals lactate, which means they do what?”

A buzzer rings almost before Zahren finishes the question. “Make milk?”

Caitlin Shaw, 10, the captain of the Northview Elementary team, gives her school an early lead in their game against Woodridge Elementary.

Instead of scoring baskets or kicking field goals, Caitlin and her team of three are answering trivia questions in the Science Bowl, an annual competition among 40 elementary schools and 16 middle schools in Prince George’s County, Maryland. In the competition, now in its 30th year, teams go head to head in the fall and winter, with two elementary and two middle schools reaching the finals in March. The games are recorded for broadcast on local television and posting on YouTube.

Questions come from such categories as “Green Things,” “Let’s Get Physical” and “Science Potpourri,” and are worth between five and 25 points depending on the difficulty.

Dave Zahren — “Mister Z” — waits for a student to reply during a Science Bowl match between two elementary schools. Correct answers are worth five to 25 points. (Harrison Smith/The Washington Post)

If you knew what “lactate” meant, other questions — such as where cells called hepatocytes are found — might trip you up. (The answer is the liver, the body’s largest internal organ.)

Caitlin and her team from Northview, in Bowie, weren’t stumped often in their game against Woodridge, which is in Hyattsville. After correctly answering a question on precipitation, Northview won narrowly, 180-175.

“That was nerve-racking!” said Eric Harris-Beckham, 10. “I was really nervous at the beginning, but then it was really, really fun.”

The team of Eric, Caitlin and Liya Solomon, who is also 10, were clearly into the science theme. They wore white lab coats for the game, and they even brought a mascot: a battery-powered toy named Science Bowl Bot that their alternate player, Sidney Beyea, built from a kit. It sits on their podium during games.

Like most other teams, they were selected to play in the Science Bowl by teachers at their school, and they prepared by watching videos of past games and studying science terms and the periodic table of the elements.

This was also the first time they had been in a professional TV studio, they said.

Filmed at the Bonnie F. Johns Educational Media Center in Landover, the Science Bowl features studio lighting and three cameras operated by high school interns — everything but a live audience.

Zahren, a former middle school science teacher, is the “Jeopardy”-style game’s Alex Trebek. He comes up with each question and estimates that he asked his 50,000th question this fall.

His face lights up when he finishes the last game of the day: another victory for Northview, over Rockledge Elementary School in Bowie.

“We won! We’re going to the semifinals!” says Sidney, running into the studio to greet her teammates. Northview will play Magnolia Elementary School, from Lanham, in a semifinal game February 9.

“Make sure you bring that to every game,” says Liya, handing Sidney the Science Bowl Bot.

“It’s our good-luck charm.”