Imagine a day with 37 more minutes ...

What would you do with an extra 37 minutes each day? Or an extra 3 hours a week?

If you're 14-year-old Cody Scarpella, you'd probably spend that little bit of extra time gazing through a telescope at the stars and planets in Idaho's dark night sky.

Cody will soon be able to look up and know he is helping others comprehend the complexities of at least one of those planets - Mars, a planet that twirls just a tad slower than Earth (roughly 37 minutes a day, in fact).

The first Martian sundial, adorned with Cody and his classmates' designs, will help students worldwide understand the link between time units and planetary motion, says Sheri Klug, outreach coordinator for the Mars research program at Arizona State University here.

The three-inch-wide aluminum instrument will ride on a NASA spacecraft due to land there in January 2002, and photos of it will be transmitted via the Internet.

"It'll be pretty cool to look at Mars and know something I did is up there," says the budding young scientist.

Cody's idea for decorating the dial with hand-holding stick figures was one of several student suggestions incorporated into the final design. His science teacher at Lake Hazel Middle School in Meridian, Idaho, gave him the good news April 30. Design ideas from his classmates Dang Du, Sarah Williams, and Amanda Pratt will also appear in the sundial's ornamentation.

The sundial is a bonus addition to the instruments currently being prepared for NASA's Mars Surveyor 2001 lander. It originally began as a calibration target for the craft's panorama camera. The gray scale, colors, and shadow on the target will help scientists interpret what they see in the camera's photos.

"It will be the most photographed thing on Mars," Ms. Klug says.

Last fall, some of those working on the spacecraft realized they could make the target double as a sundial without adding weight.

Klug and Bill Nye, host of a children's science TV program, "Bill Nye, The Science Guy," invited educators at a science-teachers conference in Seattle last October to ask students for pictures and messages to include on the sundial.

Suggestions and sketches arrived from about 160 students in six states. Several students proposed displaying the word Mars in many languages, and several others sketched figures to show the diversity of people on Earth.

Names for the Red Planet in 24 languages will be engraved on the dial. Lively stick figures, drawings of a rocket and Mars rover, and seven sentences describing the mission will fill side panels around the sundial's base.

"We sent this craft in peace to learn about Mars's past and our future," says part of the description.

Arizona State University, which is also preparing a mineral-identifying instrument for the lander, is creating the sundial this month.

Cody's eighth-grade science teacher, Marg Freeman, says the sundial project has helped students appreciate comparisons between Earth and other planets in the solar system.

Because the Martian day, called a "sol," lasts 24 hours and 37 minutes, scientists who operated the Pathfinder and its rover on Mars in 1997 worked on the sol schedule, which quickly got them out of sync with Earth's day-night cycle.

"We haven't really addressed what a month is on Mars," Klug says. "A month on Earth is based on the lunar cycle, but Mars has two moons. It will be something for students to think about."