The city will pay $60 million over two years to implement a new universal science curriculum in the lower grades, the mayor announced yesterday.

The announcement comes after national science test scores released in November showed that more than half of New York City students who were tested had failed last year, a percentage far below the national average. Starting next school year, federal No Child Left Behind regulations require all states to test students in science three times throughout their school career, something New York State already does.

The curriculum — for kindergarten to eighth grade — will be coupled with new citywide tests that also will be rolled out over the next two years. The science test scores will factor into progress reports for schools and eventually may be used in student promotion decisions, Chancellor Joel Klein said.

“It’s not enough to merely encourage our young people to achieve. We must give the tools to do so,” Mayor Bloomberg said after acknowledging that the city has “a long ways to go.”

Schools will be able to choose what parts of the curriculum they will adopt from among a restricted set of options, including experiment-based or more traditional textbook-based courses, and some schools may be able to apply for a waiver.

Department of Education officials said they will announce the companies that are being contracted to create the curriculum in the coming months, and that those contracted will be companies that already work with the department.

The deputy chancellor for teaching and learning, Andres Alonso, said the department chose research-based curricula and also looked at the science programs used in cities that scored well on the national test.

Mr. Alonso said the department decided to implement the curriculum now, instead of two years ago, when new citywide literacy and math curricula were implemented, because it “would have been impossible” to do all of them at the same time.

“Now I think we’re ready,” he said.

The president of the United Federation of Teachers, Randi Weingarten, praised the new curriculum.

“A well-rounded curriculum has to include more than math and English. Science, social studies, and the arts also are critical,” she said. “It’s great that the city has recognized that, at least for science.”

Mr. Klein has said the city plans to implement a citywide social studies curriculum in the 2008–09 school year.