THE IDEA OF ATTENDING an all-day class on a weekend might sound unappealing to middle-schoolers -- until they learn that the course provides a foundation for going into the business of baby-sitting.

Many kids about age 12 want to start caring for younger children and earning money but have little or no experience. A baby-sitting safety class, typically lasting at least five hours on a Saturday or Sunday, helps preteens and teenagers learn basic skills and gain confidence. Students cover a variety of topics, including setting up a business plan and staying levelheaded during a crisis. At the end of the course, each participant receives a certificate, an impressive credential to whip out and show prospective employers.

"All the questions I had were answered, so I feel more confident baby-sitting other people's children," said 12-year-old Sophie Goewey of Vienna, who took a Babysitting Fundamentals class recently at the Vienna Community Center. Before that, she had watched her 6-year-old brother and 9-year-old sister, but she wanted to branch out and care for other kids on her street.

On a recent Saturday at the Vienna facility's teen center, instructor Diane Hale asked 26 students their motivation for being there. "Other than the fact that it's going to rain today, why are you here? Why do you want to baby-sit?" She then ran through a list of incentives, including earning money, gaining job experience, demonstrating responsibility and playing with children.

"You are there to play with children and keep them safe," she told her class. "That is your responsibility, period."

Hale followed a format of part lecture, part hands-on learning, which is typical of baby-sitting classes. Middle-schoolers learned about setting wages ($4 to $8 an hour) and keeping a record for each family, including such information as children's names, allergies and current weights and ages. They took notes in workbooks, which they would keep for reference.

Hale gave some do's and don'ts: Do arrive at least 15 minutes early, do bring your own snacks, but don't baby-sit if you or the children are sick or if you have a lot of studying to do.

"Your education is a lot more important than me seeing the next Mel Gibson movie," said Hale, speaking as a parent of two.

The class broke into small groups for discussions and activities, such as listing developmental traits of different ages and devising kid-friendly activities using a few simple materials.

The course also covered crisis-prevention techniques, such as calming children's fears, keeping kids away from potentially poisonous substances and dealing with emergencies like choking.

"We learned how to use a Heimlich maneuver, which I didn't know how to do before," said Julia Horowitz, 11, of Oakton, sounding ready to enter the work force as a fresh-faced wage earner and caregiver.

Julia Lewis, 12, of Chevy Chase practices changing a diaper on a doll during an American Red Cross baby-sitting safety class. Julia Lewis and her charge during baby-sitting class.