When Beers Elementary School in Southeast Washington was picked as a test site for a model science program two years ago, Ngwah-Mbo Nkweti was a C student. Now, the $60,000 in resources provided by private firms has helped her turn a C in science into an A.

Gloria Tucker, a Beers science teacher for 15 years, said Nkweti improved her comprehension by working with modern equipment in the school laboratory, which contains supplies donated by several corporations that sponsor the Model Elementary Science Program there.

With the "hands-on experience" she gains by working with high-quality scientific equipment and computers, she learns more than she could by simply reading textbook lessons, said Nkweti, 10. "I understand science better now. It's fun," Nkweti said. "The equipment helped me to do better. It made it easier to do experiments."

While she marvels at her improved grades, D.C. Public School officials point to her progress and that of other students as proof that the school system is reaping benefits from an increasing number of donations from corporations, trade associations and foundations.

In recent years, school systems across the country have pursued corporate donations with a new intensity to offset budget restrictions. To help their efforts, the Council of Great City Schools, which provides research and information to 35 major city school systems, is drafting legislation designed to give corporations more tax credits for donations to schools, a spokesman said.

Since 1981, the D.C. schools have received $5 million in computers, scientific equipment, money and other resources from large corporations. The school system has spent $10 million from its own budget for school equipment and supplies in the past three years.

"There are many city schools that receive donations from private industry, but normally not to the extent that the D.C. schools do," said Michael Casserly, legislative and research associate for the council.

Prince George's County schools, for example, have received less than $500,000 in recent years. Fairfax County schools began seeking corporate gifts last year and have received about $1 million, officials said.

"Most of what you see in other cities is the private sector using adopt-a-school programs similar to what the White House is doing, which normally do not involve direct grants but involve visits from industry officials ," Casserly said.

Casserly said the firms, in turn, reap immediate public relations benefits with their gifts. But the bottom line is that "the private sector has very much of a stake in ensuring the health of the public schools."

Although some of the equipment was loaned on a temporary basis for test projects, school officials said the corporate involvement has helped students learn more and created opportunities for career growth. Among the largest gifts are:

* An engineering program sponsored by General Motors Corp., International Business Machines and Potomac Electric Power Co. at Dunbar High School in Northwest. Program managers lecture at the school, teachers are sent to the General Motors Institute in Michigan for training, and $40,000 in computer equipment is loaned to the school.

* The National Savings and Trust Bank, D.C. Bankers Association and Blue Cross/Blue Shield insurance company direct a business and finance program at Woodson High School in Northeast Washington.

* IBM sponsors the "Writing to Read" program at 15 elementary schools througout the city. Under the $500,000 program, kindergarten and first-grade pupils learn to read, write, spell and type on specially programmed computers.

* Mobil Corp. sponsors a $616,000 program operated in dozens of schools by Young Audiences, a nonprofit group that brings professional artists, musicians and other performers into classrooms and auditoriums to play and teach.

School officials and teachers say that public-private partnership programs are essential to prepare students to compete in high-tech job markets.

"If we are to continue to have progress, we're going to have to have more participation from the private sector," said District school board vice president Nate Bush (Ward 7). "In the long run, corporate involvement is going to give the private sector a more educated and better work force."

Beers science teacher Tucker, who coordinates the model science program there, added, "Every little bit helps. When we can't get money from the federal or District government, then we have to rely on private industry to form partnerships and give gifts."

She said the Model Elementary Science Program replaced the "shoebox operation" of "boring" textbooks and simple objects such as soda bottles, metal rings, clothespins and strings usually stored in used shoeboxes.

Now Beers students have a science laboratory equipped with $20,000 worth of kits, a specially designed sink for group experiments, and professional measuring devices to teach math and science skills. About $40,000 in computer equipment was given to the school as well.

School officials said the search for corporate gifts was spurred four years ago by President Reagan, who promised in 1980 to reduce govenment spending while urging the private sector to take a more active role in supplying resources.

Though the school budgets have not been reduced in recent years, James Guines, D.C.'s associate superintendent for curriculum, said, "Education was one major area that was to be affected. President Reagan said if local districts were aggressive, then private corporations would respond to their needs. That's what happened for us."

Kent Cushenberry, corporate director of community relations and government programs for IBM, said, "We have contributed to D.C. schools people on loan who have certain expertise and skills and equipment in pilot programs that assist in writing, reading and arithmetic. And we're doing this because we support the effort of the business-education partnerships."

While corporations often give the largest gifts to schools, residents, politicians and small community and parent groups also contribute meaningful assistance, said School Superintendent Floretta D. McKenzie.

Last year, Reagan and an organization operated under the private sector initiatives office in the White House gave about $20,000 in materials to the Martin Luther King Jr. Elementary School, McKenzie said.

The White House Friends gave an earth satellite dish, a remote-controlled satellite receiver and a remote-controlled antenna. Mayor Marion Barry gave $1,000 for a math tutor and computer software to two elementary schools, and the Mayor's Escheated Estates Funds office gave $10,000 to Gordon Elementary School to buy word processors.

School board members, PTA groups, other nonprofit organizations and residents donated more than $100,000 to improve schools of their choice in a variety of ways. The United Black Fund, for instance, gave $1,500 to the Olympics of the Mind program, and the president of the fund, Calvin Rolark, gave $500 to a Ballou athlete to go to the Olympic Games in Los Angeles last summer, McKenzie said.

Most of the partnerships between schools and firms are not bound by contracts, so they could end at any time, Guines said, but, "We hope that the partnerships will never change, now that we're working together."