PALM DESERT, Calif. -

Palm Desert Charter Middle School eighth-grader Katie Peterson is among the 281 students competing today in the Scripps National Spelling Bee in Oxon Hill, Md., which has incorporated vocabulary questions for the first time.

The contestants took computer-based spelling and vocabulary tests Tuesday, which are considered the first round of the bee. They will take to the stage at the Gaylord National Resort and Convention Center today for the second and third rounds, where they will attempt to correctly spell one word each.

Contestants misspelling a word will be eliminated.

Those who spelled both words correctly have the chance to be among the maximum of 50 spellers advancing to Thursday's semifinals, depending on how well they did on Tuesday's tests.

Adding the vocabulary questions "is a significant change in the Scripps National Spelling Bee, but also a natural one," said Paige Kimble, the bee's executive director and its 1981 champion.

"It represents a deepening of the bee's commitment to its purpose -- to help students improve their spelling, increase their vocabularies, learn concepts and develop English usage that will help them all their lives."

Katie is 14, the president of her school's Renaissance Leadership class and a former president of its California Junior Scholarship Federation chapter. Her favorite subject is science and she wants to be a surgeon when she grows up.

The bee is limited to students in eighth grade or below, with contestants ranging in age from 8 to 14 years old.

The winner of the bee will receive $30,000 from Scripps, a $2,500 U.S. savings bond and complete reference library from the dictionary publisher Merriam-Webster, and $2,000 in reference works from Encyclopaedia Britannica.

The semifinal and championship rounds will be held Thursday, with a contestant eliminated after he or she misspells a word.