From timeless questions like “What works better for getting chewing gum out of hair: cooking oil or peanut butter” and “Is a dog’s mouth cleaner than a human’s,” to more complicated queries such as the effects of ocean acidification on mussel shells, 335 budding scientists from four parishes spent Wednesday educating judges on their findings.

The 57th annual Greater New Orleans Science and Engineering Fair, hosted at the University of New Orleans with Tulane University, is one of the oldest of its kind in the nation. Middle and high school students from Jefferson, Orleans, Plaquemines and St. Bernard parishes competed for prizes as well as a spot in the State Science Fair in Baton Rouge next month and the International Science and Engineering Fair in Phoenix, Ariz., in May.

In the junior division, middle school students entered projects falling under seven categories, including physics, earth science and chemistry. They looked at whether a runner’s choice of shoe makes a difference in speed, the harmful affects of acidity in drinks, whether rooftop gardens lower utility bills, an insect’s favorite color and the best way to remove grape juice stains.

Wesley Hodgson, a student at Atonement Lutheran School, decided to examine the effects of different types of music on the growth of the pothos vine. For three hours a night over a four-week period, the plants were exposed to classical music in his parents’ room, country music in his bedroom and rock music in the bathroom. Another set of plants was not exposed to any music.

Hodgson said he was not surprised that the plants did not thrive with the rock music, but he was surprised that they appeared to prefer country music over classical music. A music lover, Hodgson said he debated playing the piano for the plants himself, but that it would be too time-consuming.

Luke Snee, a student at T.H. Harris Middle School, wanted to figure out if he could calculate the diameter of the sun using math. With a piece of cardboard partly covered with aluminum foil and a pinhole, he used ratios and proportions to calculate a diameter of 873,391 miles. Snee said his results were just 1.6 percent off the actual diameter — “Not bad for an eighth-grader,” he said.

At John Curtis Christian School, Alyssa Roux set out to show that storm surge should be part of categorizing a hurricane’s strength along with wind speed. Roux said that after watching Hurricane Isaac pass, she thought that the storm surge was just as, if not more, dangerous than wind speed. Using a fan and a plastic tray with water, Roux said she looked at wind direction and tidal changes in addition to wind speed.

Haynes Academy student Injee Hong found that out of four meats, lamb had the most antibiotic-resistant bacteria.

She had guessed chicken, Hong said, and added that she was interested in looking at more variables and conducting further research.

Testing the differences between spring water, purified water and tap water, T.H. Harris student Angela Truxillo found that there was no evidence that bottled water was better than tap water.

She said she became interested in the topic because she likes to drink tap water and wondered if it was safe.

Tasting three varieties of hot peppers, Atonement student Jared Brodtmann said his love of spicy food inspired him to determine capsaicin’s effects on the body’s vital signs.

Habanero peppers spiked his pulse rate and blood pressure every time, he said, with only a slight rise in body temperature.

In the senior division, high school students competed in 17 categories, including behavioral and social science, cellular and molecular biology, energy and transportation and environmental management.

Students probed the effectiveness of acne medication, Hesco baskets and different types of home insulation.

They questioned whether exposure to low levels of radio frequency from cellphones will decrease the life expectancy of crickets, the effects of salinity on marsh grass, whether magnetic beads can reduce peanut allergens and the effects of rewards or punishments on student quiz grades.

Siddesh Ponnapakkam, a student at Haynes Academy, researched water quality in the stretch of southern Louisiana known as “cancer alley.”

He said his interest was piqued by a 1987 study of 15 cancer patients living in a single block in St. Gabriel. Ponnapakkam said he took samples of water from the Mississippi River in four parishes.

Everything was within limits, he said, but he was surprised to find measurable results of selenium in the water at two locations near power plants.

Using three dogs and three humans, Holy Cross School student Eddie Burgard used swabs to measure the bacteria in each mouth.

The dogs’ mouths had significantly more bacteria than the humans’ mouths, Burgard said. A dog lover, Burgard said that he is less inclined toward his dog’s slobbery kisses after the experiment.

He also noted that two of the dogs were cooperative and one was not.

Norma Jean Mattei, one of the fair’s judges and the UNO department chairwoman for civil and environmental engineering, said she thinks her industry should be doing a better job at recruiting females.

At the fair, female students made up 49 percent of the participants, but Mattei noted that in engineering, women make up only about 16 percent of the workforce.

She said that if young people had a better understanding of the significance of engineering on quality of everyday life — and an engineer’s potential to positively affect society — more females would pursue the field.

Getting the students at the fair connected to mentors who work in the different scientific fields is a good way to promote futures in science, technology, engineering and mathematics education, Mattei said.

For members of the public who want to know the best environmentally friendly detergent for getting ketchup stains out of socks, whether fingernail polish remover can kill red worms, or if orange juice has more electrolytes than sports drinks, the students’ projects will be on display from 9 a.m. until noon Thursday.

An awards ceremony will be held Friday.