A sophisticated array of exhibits in the fields of solar energy, biochemistry, computers and robotics won awards for D.C. student scientists at last weekend's citywide science fair.

Grand-prize winners were Lisa Marie Thompson, 17, of Fort Chaplin, a senior at H. D. Woodson High School, whose solar energy project took top honors in the engineering category, and John Stasko, 14, of Fort Washington, Md., a 10th grader at Archbishop Carroll High School, whose experiment involving amino acids won the highest award in biochemistry. The fair was held at Woodson High in Northeast.

Thompson and Stasko will represent the District at the International Science and Engineering Fair in Milwaukee May 7-11. Approximately 450 junior and senior high school students will compete.

Last weekend's D.C. fair attracted nearly 400 entrants, compared with 280 last year, according to Mary B. Harbeck, supervising director for science for the D.C. public schools.

The fair, in its 35th year, is coordinated through the science departments in the D.C. public schools and is open to students in grades seven through 12 who are attending public, private and parochial schools in the District.

Funding for the fair is provided by the D.C. schools and the D.C. Science Fair Association, a group of local teachers and scientists, Harbeck said.

Thompson won her grand prize for designing a solar energy system for her family's town house. "The research was easy," she said. "The challenge was applying the information." Thompson expects to attend Syracuse University in the fall and study civil engineering.

Stasko, the other grand-prize winner, entered a biochemistry experiment that demonstrated that amino acids can be formed from inorganic substances. Flanked by a Bunsen burner piled high with flasks, tubes and glass bottles, Stasko said, "The main premise of my project was to show that living things may be created from nonliving things." Last year Stasko won a grand prize at the Prince George's County science fair and looks forward to a career in science, although he is not sure in which field.

Sherron Benn, 16, of Brightwood, a junior at Ballou High School, is a veteran competitor, having one second place two years in a row in the field of microbiology. This year she was runner-up grand-prize winner with a project demonstrating how the human body handles E. coli bacteria. Assisted by specialists at the Walter Reed U.S. Army Medical Center, Benn spent three months working on the exhibit. An honor student, she wants to be a doctor, perhaps specializing in immunology.

Betabot, a second-generation manually operated robot, won a first prize in the engineering field for Daniel DiLorenzo, 15, of Oxon Hill, Md., a ninth grader at Gonzaga College High School. Betabot is larger and much sturdier than his predecessor Alpha, and rests on a steel frame with a plexiglass covering. DiLorenzo has been building computers and robots since the sixth grade and has plans to develop "work force robots."

"The functional Betabot even has become a playmate for my 3-year-old brother," DiLorenzo said.

Valerie Adegbite, 16, of Fort Chaplin, said she respect for the "knowledge and accumulated wisdom" of senior citizens led her to do a demographic breakdown of the mortality rate of the aged in the United States, Sweden and Trinidad, a project which placed first in the mathematics and computer category. A runner-up grand-prize winner, Adegbite plans to pursue a medical career at Howard University.

Kevin Koch, 16, of Hyattsville, Md., a 10th grader at Archbishop Carroll High School, is no stranger to science fairs, having exhibited at several Maryland county fairs. This year's exhibit, in the behavioral and social science category, involved observing the effects of refined sugar on rats. By feeding six rats varying amounts of refined sugar for 11 days, Koch found that the rats fed no sugar were less nervous and ran the maze faster. Asked about his career plans, Koch shrugged his shoulders, saying, "I just want to be rich."

First-place winners and their schools are:

Daniel Gordon, Michael Lapriola, John O'Brien and John Stasko, Archbishop Carroll High; Felicia Sallis, Ballou High.

Also, Kenneth Bolding, Robert Bumbary Jr., Michael Catafosta, Michael Curtain Jr., Daniel DiLorenzo, James Mackey IV, Jeffrey P. Muench and Daniel Parker, Gonzaga College High.

Valerie Adegbite, Pamela R. Gilliam, Lorita Miller and Lisa Thompson, Woodson High.

Sonja Herbert, Brent Junior High; Todd Ford, Deal Junior High; Charles Morris, Francis Junior High; Jacqueline Kearney and Tracey McMillian, Garnet-Patterson Junior High; Barry Silver, Hardy Middle School.

Marshall Jackson, Michelle Jackson and Chris Littlefield, Jefferson Junior High; Jerome Booker, Kramer Junior High; Kris Levine and Jonathan Weiswasser, Maret Middle School; Dennis C. Bobo, Pamela Bright and Cara Woodson, Rabaut Junior High.

Jack A. Gullo, Jay Harrison, Patrick Spaulding and Bridget K. Touhey, Blessed Sacrament School.