While many mothers may tell their children to act more like adults, 15 suburban Maryland moms are spending a lot of time acting like children.

The Picture Book Players, who perform for young children at Glen Echo's Adventure Theatre, are mothers whose aim is to prepare youngsters for life's experiences and to teach them life's rules through the arts.

The group's 15 members have been performing every Thursday morning from November through May since 1974--about 21 performances a year. Their audience at a recent performance--about 200 children, most of them 4 and 5 years old--watched the mothers, who wear children's costumes, sing, dance and romp in front of colorful sets.

"Sam-The Rules of Life" is the group's latest production, an hour-long action-packed musical geared for children ages 3 to 10. For the last three years, Barbara Dove of Bethesda has created original musicals for the group with the help of Midge Davis.

Dove says the show "goes beyond entertainment. Our goal is to serve as a useful educational experience.

"Children have problems at home--sibling rivalry, adjusting to school, making friends, etc.--and we try to help the kids see how to deal with them. We want them to know they are not going solo with their problems."

"Sam" traces the life of a child from infancy to about 10, going through several life experiences aimed at giving the audience a message, such as the value of sharing and how to make friends.

Several times during the show the performers step into the audience to shake small hands. They also ask the children to participate from their seats by stretching and moving in place, or by asking questions at the end of the show.

Pianist and occasional drummer Linda Coleman, alternating with Davis and Janet Lindgren, plays the musical's score, "largely from memory with occasional ad lib," she says.

Dove, who teaches creative drama at Glen Echo and other D.C. schools, says that she came to the group "to not only have a good time but also to deliver good messages in a very low-key way. It's fun to both teach and learn through theater."

Picture Book Players is self-supporting, working without pay. Its shows are free. Last Christmas Eve, the group performed at the Holiday Festival at the Kennedy Center. Dove is planning to work on a new musical this summer and said she wants to extend its scope to 10- to 12-year-olds, dealing with more teen-age problems that revolve around the family, the neighborhood and school.

The group, composed of all mothers whose average age is 33, rehearses on Mondays.

Cassette tapes of the show, available at $4 each, contain lyrics and music on such themes, as friendship, health, wealth and loving your neighbor.

Dove would like to see Picture Book Players travel to other theaters. "We need more good children's theater in this area," she says.