SHIRLEY -- Ayer-Shirley Middle School was abuzz with activity on a recent Saturday morning, with the annual Science Fair in the gym and a book fair in the library.

Entering the gym, visitors to the Science Fair were greeted by Ayer-Shirley Education Foundation members. Fifth-graders were invited to take a "passport" from the table.

Questions inside the "passport" included what they learned at the science fair, which exhibit they enjoyed and why, and a "scavenger hunt" checklist of things to look for, such as a bar graph, pie chart and different kinds of experiments.

According to ASEF member Sheila Kelly, the idea behind the passport is to grow Science Fair attendance among the younger students and, hopefully, spark interest in participating when they're in middle school next year. A prize adds a more immediate incentive. The fifth-grade classroom with the most students attending won a pizza party, Kelly said.

Arrayed around the gym, 64 exhibits showcased a diverse lineup of student projects with such intriguing titles as "Under Cover Sneeze," "Peppermint Power," "Blinking for Interest," "Paintball Statistics," "Hot Dog Mummification," "I Smile You Smile," "Fastest Way to Cool a Soda" and "You Get What You Pay For," among others.

Criteria for project presentations included framing a thesis and proving or disproving it, using the scientific method.

Questions asked, dilemmas solved, curiosity piqued, even failures lead to learning. That's what school science projects are all about.

Sixth-, seventh- and eighth-graders stationed at the booths were well prepared to demonstrate and explain their exhibits as visitors asked questions. All interesting and neatly displayed, some were more hands-on than others.

"Catapults -- Bombs Away," for example.

Eighth-grade project partners James Caires and Jeffrey Gendron ably demonstrated how they tested physics principles using a model catapult they'd made -- with some help from Jeff's dad -- of wood, bungee cords, tin cans, tape and screws.

Pulled back all the way and released, how far would the arm of this simple machine lob a tennis ball from one of three halved tin cans set at different heights on the arm? As anticipated, the ball on top traveled farthest, 2.5 feet, while the bottom ball landed 1.5 feet from the point of origin.

In his "Musical Plants" experiment, seventh-grader Liam Mountford determined that, contrary to whimsical wisdom about music helping plants grow faster, the theory in practice didn't work for his bean plants.

With impressive aplomb, he described his test techniques and the results, pointing to each of several plants, potted in red plastic cups. All green and clearly alive, some were taller and looked healthier than others. One was a bit droopy.

The information came in a torrent, and a visitor with no botanical experience had some trouble following, but the gist of it was this: Liam placed plants in different locales under a variety of conditions. A dark closet versus a light-filled space, for instance, with and without classical music playing on a portable stereo.

He observed that serenaded plants didn't seem to benefit from the musical experience, either wilting in the dark or growing slower than silently raised plants placed under lights, which thrived. His conclusion: Music didn't affect the plants, one way or the other.

Tim Holmes and Ryan Fillebrown, both eighth-graders, drew sports-minded onlookers with their experiment, "In the Zone." Beside the triptych, which laid out their theory, test methods and results in text and pictures, a video showed the experiment in action.

Working with 10 middle-school subjects -- boys and girls, some experienced players, others not -- the researchers sought to find out which basketball shots were most often successful.

On the court in the middle-school gym, the test subjects tried lay-ups, jump shots and 3-pointers, 10 each. As anticipated, lay-ups trumped the other two types, succeeding 59 percent of the time, versus 19 percent for jump shots and 16 percent for 3-pointer.

Sixth-grader Fiona Kelly's experiment, "Cup Communication" sought to find out which type of string conveys the most audible sound from one cup to another. 

Her models consisted of equal lengths of four different types of strings poked through the bottom of a pair of plastic cups and stretched 10 feet apart, connecting them like twin telephone receivers. Sounds familiar, doesn't it? Like the cup-and-string contraptions that kids of another generation might make to place "long-distance phone calls" across backyards.

But rather than recreating an old-fashioned voice-messaging system, the aim of the experiment was to discover high-tech details in a low-tech communication model, using simple, scientific methods and modern devices to achieve the stated goal.

Fiona used cellphone tones and a decibel meter to conduct her trials.

Using monofilament and other fishing line in various strengths, measured in pounds, she found that the 36-pound, wax-coated line produced the loudest sound. The string is denser due to the wax, which boosts the sound intensity, Fiona said.

Results were 86.53 decibels for the 4-pound line, 90.26 for the 50-pound line, 96.4 for the 20-pound line, and 98.3 for the waxed line.

Asked why she chose this particular point to ponder, Fiona, who plays acoustic piano, said the how and why of sounds produced by strings interested her.

Projects were judged, with the top 10 overall winners eligible to participate in the Regional School Science Fair in May. With one tie, there were 11 winners.

ASEF member Paula Gravel announced the winners when the event wrapped up at noon. She also noted that this year's Science Fair was jointly sponsored by the Ayer Shirley Education Foundation and Creative Materials, with company headquarters in Ayer.

Fiona Kelly placed first in her grade level and won top billing overall.

The other top winners and their projects, all eligible for the regional fair, are listed below.

* T.J. Cooper, grade 8, "Stealthy Shapes."

* Natalie Carroll and Marie Morales, grade 8, "Rubber Bands for Energy."

* Hayley Sheriff, Gracie Soultanian and Hannah Justice, grade 6, "Perfect Spot to get the Perfect Shot."

* Nick House, grade 8, "Sound vs. Light."

* Jenn McGraft and Sarah Arnst, grade 8, "Is Wimbledon Right?"

* Jeffrey Gendron and James Caires, grade 8, "Catapults -- Bombs Away."

* Jason Langlais, T.J. Fleming and Bryce Valliere, grade 6, "Food Energy."

* Allison Steeves, grade 8, "Our Negative Memory."

* Jarrod Oberg, grade 8, "Can Water Float on Water?"

* Emmitt Boyd, grade 8, "Orange You Glad it Has Voltage?"

First, second and third-place winners, by grade level:

Grade 6: Fiona Kelly, "Cup Communication, "first place; Hayley Sheriff, Gracie Soultanian and Hannah Justice, "Perfect Spot for the Perfect Shot," second place; Jason Langlais, T.J. Fleming and Bryce Valliere, "Food Energy," third place.

Grade 7: Liam Mountford, "Musical Plants," first place; Jake Minear, Leigh Wilson and Aiden Fish, "Can You Fry Ice Cream?," second place; Alyssa Lauderback and Haylee Harmon, "Coke and Mentos."

Grade 8: T.J. Cooper, "Stealthy Shapes," first place; Natalie Carroll, Marie Morales, Bradleigh Shultz, "Rubber Bands for Energy," second place; Nick House, "Sound vs. Light," third place.

Note: Eighth-grade student participation was mandatory. Others took part voluntarily.