When Sonya Lawson comes to Rosemont Elementary School in Gaithersburg twice a week to dance and act for 3 and 4 year olds, she is not there just to entertain.

Her hour of singing, acting and moving around the the classroom is designed to help improve the counting, memory and languange skills of 15 preschoolers. The Wolf Trap Foundation, sponsor of the program that sends Lawson and three dozen other artists to Head Start classrooms around the area, also hopes the students are acquiring some appreciation of the arts early in their lives.

The program, one of the education programs administered by the nonprofit arts foundation based at the Wolf Trap Farm Park in Vienna, is funded by a $150,000 grant from the U.S. Department of Health and Human Services.

In the past year, the artists have taught more than 5,000 children in 100 day-care centers, including about 1,100 children in Maryland. Artists are teaching in 11 Head Start facilities in Montgomery County and were in Prince George's County centers last fall.

Local dancers, singers, mimes, actors and storytellers participate in the program sponsored by Wolf Trap to encourage an awareness of arts by training teachers, children and parents. Artists include Ketter Betts, an internationally renowned bass player who accompanies Ella Fitzgerald, and Michele Valeri, a professional musician and drama specialist who has made records for children.

The 2-year-old Wolf Trap program also trains day-care center teachers in the use of arts in the classroom and counsels parents on how to promote continued learning at home.

The program includes weekly field trips to Wolf Trap Farm Park for the students, 60 at a time, to work with dancers based there.

The participating artists "are the finest in the Washington area," said Janice McKelvey, coordinator of Wolf Trap's community service programs.

The teachers say they look forward to the sessions.

"I come alive and forget about my problems because that's such a special world--an open free environment," said Lawson, who teaches 12 workshops a week in Montgomery classrooms. "It's a world of discovery for the children, and I'm there to share whatever I have learned."

Cathy Fink, a musician who lives in Takoma Park, believes involving children in the arts helps improve their self-images. "It makes them feel special and important," said Fink, who teaches twice a week at Mill Creektowne Elementary in Rockville.

Sheila Miller, a teacher at Oakcrest Elementary in Landover, said the program fills a void because her school is unable to afford to send children on field trips to see artists perform. "The kids have never been exposed to anything like this before. "They the artists love their work and it shows," she said.

To an observer, a Wolf Trap class seems like a play period. But officials of the program say the children are learning language skills, colors, body movement, concentration, the ability to follow directions and a host of other skills.

In Fairfax County, the program is cited as a possible reason for higher test scores of preschool children. Fairfax students are tested once in the fall and again in the spring to determine their skill weaknesses and strengths. Prior to the introduction of the Wolf Trap program, children averaged a seven-point increase in test scores, a Fairfax Head Start official said. In May 1982, after a year of artists' visits to the classrooms, test scores rose by 25 points.

Sandra Lowe, Head Start coordinator for Fairfax, attributed the increase to a combination of factors but added, "Wolf Trap was there as an extra stimulant."

No similar test scores are available in Maryland, but school officials believe the program is working. "We know the kids are much more open. They look forward to it," a Prince George's school official said.

"The program gives so much joy to the children," said Sakineh Walther of Rockville, whose 4-year-old child, Michele, attends the Head Start program at Maryvale Elementary in Rockville. "The artist is the highlight of their day."

Walther said her daughter is always coming home with new songs after a session with a Wolf Trap artist. "Michele goes around the house singing the songs and is so happy it makes us happy," she said.

One Brentwood parent maintains that a Wolf Trap artist helped her son's hyperactivity problem. Barbara Litten said she was impressed with how her 4-year-old son, Jason, was able to sit still during a ballet performance given for the children of the Mount Rainier Head Start program at Wolf Trap. She said an artist also was able to work with and improve Jason's problem of talking too loudly.

"Jason would look forward to going to school on Monday," Litten said. She said the exposure of music given to Jason by the artists was unique. "Now he wants to play the drums."

The philosophy of the program is simple. "We show the children that they are artists," program coordinator McKelvey said. "We show them that they are talented human beings and that talent should be shared with others."