So were the 35 other seventh graders and their two teachers from Radnor Township Middle School, a Delaware County public school.
"Mike's one of our water rats; he loves to be in the water," teacher Mark Springer was saying, standing on the rocky bank of the creek.
Buck was drenching himself to measure the depth of the creek.
Others - boys and girls alike - were plunging knee-deep and thigh-deep into the 40-degree stream.
Some were taking water samples that showed oxygen and carbon dioxide levels high enough for a healthy stream. Some were looking under rocks in the stream and finding insects that suggested how healthy were the lives dependent on the stream.
It was the first trip for the class to the Brandywine Creek since January. It was the 12th creek trip for them since classes began in September. It was their 20th trip since then to the valley.
The valley and the creek are their classroom.
For this entire school year, this class is focusing on the Brandywine Valley and its creek, which rises in northwestern Chester County, courses through artists' country near Chadds Ford and empties into the Delaware River at Wilmington.
History, they learn through the Brandywine.
English, they learn through the Brandywine.
Science, they learn through the Brandywine.
Art, photography, physical education, they learn them all through the Brandywine.
"It isn't the particular watershed" that's important, Springer explained in an interview a couple of days before the trip to the creek. "It's the philosophy and approach to learning - hands-on . . . experiential and discovery-oriented."
The seventh graders are learning American history through focusing on the Battle of the Brandywine, which Gen. George Washington lost in September 1777. But that is not all.
"They do work on the 19th and 20th century and are asked to relate events in the valley to events elsewhere in the world," Springer explained.
"Some of them are involved in researching given years in the valley," Springer said.
"They have to publish a newspaper Year in Review - they're each given a specific year - that will cover . . . local news, entertainment and
culture. . . .
"They have to do biographies of famous people and not-so-famous people. They look at materials most seventh graders might not know exist - old deeds, old diaries - accentuating research skills."
This is the second year that the Brandywine experience has been offered to 36 students randomly selected by computer from the more than 150 seventh graders at Radnor Middle School.
Springer, 37, and his teaching partner, Edward Silcox, 42, developed the Brandywine program out of their work at Radnor with gifted students, those with IQs of 130 and above.
The Brandywine students "cover the entire range of IQ levels," Springer said, not just the gifted.
But, he said, "our experiences in the gifted program showed us the way students learn.
"All of our activities are geared to discover and exploration. . . . As far as I'm concerned, that's the way all students learn."
On Friday, they were learning how to share warm clothes.
"I have plenty of clothes in my bag, so don't worry," Chandal Seibert, 12, of Wayne was telling the now-drenched Mike Buck. "I have clothes for, like, 50 people."
Seibert herself was wearing tennis shoes, Bermudas and a light jacket. Not good clothes for shark-hunting.
But it was Mary Bove, 12, of Wayne, who found the shark.
"It's always great when we find a hellgrammite," Springer said when Bove brought him a water bottle with the insect.
"It's the shark of the bottom of the river. It's a good sign" to find one, he said, "because they're the largest predator of insect larvae and so they need a great deal of food."
But on a chill morning near a chill stream, exploration had its limits.
Soon Springer walked up to Silcox and said, "We've got a lot of cold people."
So they cut short the class, though some students were still - ahem - deeply immersed, and trudged back toward the warmth of a school bus.
Springer said his random questioning of teachers across the nation has found nothing similar to the Brandywine program.
"We found lots of things in New York state and Vermont, out in Wisconsin and Minnesota, as far west as Washington - where they were doing two or three- week units."
But nothing focusing on an outdoor environment for a full school year.
Walking back through the woods, Kelley Long, 12, of Rosemont, was telling what she had told someone considering the Brandywine program.
"I told him what my mom told me:
"It's the chance of a lifetime.
"And you'll get out of school a lot."