In 2011, the museum also established a separate master’s program in teaching science.

“We have a real gap in the public understanding of science at the same time when many of the most important issues have science as their foundation — human health, biology, environment, biodiversity, climate change, mass extinction,” said Ellen V. Futter, the museum’s president, during an interview at her office. “This museum has a role to play in society in terms of enhancing the role of science.”

The museum, with its dioramas, castlelike turrets, cavernous hallways and giant whale, is one of the best-known buildings in the city, partly because school trips there are such an integral part of a New York City childhood. Many others have come to know a version of it through the film “Night at the Museum.”

The expansion will probably face close scrutiny from residents of the Upper West Side. That neighborhood is known for its fierce development battles, such as the 1956 fight over the Adventure Playground at West 67th Street in Central Park, which the city’s “master builder,” Robert Moses, had wanted to turn into a new parking lot for Tavern on the Green. More recently, there were conflicts over renovation of the New-York Historical Society’s museum.

Though Central Park is only a block from the museum, proposals to reduce any open space in the city can be particularly contentious. Museum officials said that while there were no drawings yet defining the addition’s footprint, they recognize the interest in preserving city parkland, which the museum sits on. “The vast majority of the open space on the west side of the museum, between 77th and 81st Streets, will remain open space when the project is completed,” said Ann Siegel, the museum’s senior vice president for operations and capital programs.

The museum is a veteran of such debates, having successfully weathered protests over its Rose Center, which some neighbors had argued would ruin the neighborhood.