Keri Phipps pushed the ignition button on the dash of a dark blue Nissan Altima hybrid - then pushed it again, and again - waiting for the engine to show signs of life.

But two 55-gallon plastic trash bags attached to the vehicle's exhaust pipes weren't filling up.

"I'm going to buy that car when I grow up," 14-year-old Cheldelin Middle School student Mohamed Hassan exclaimed.

"Drive it forward slowly a few feet," science teacher Michael Krasilovsky urged, but the bags remained flat. "Look, there's no engine noise and the bags aren't filling up."

He then asked the more than 20 students gathered at the school's north parking lot why there were no emission gases being captured.

"Because it's a hybrid, and it's running off electricity," one of the students responded.

As part of their science unit, Krasilovsky's students tested emissions from a Honda Fit and Toyota Camry with 4-cylinder gasoline engines, a Volkswagen with a 4-cylinder diesel engine, a GMC Yukon with an 8-cylinder gasoline engine and the Nissan hybrid.

The students taped a trash bag over each of the vehicles' exhaust pipes, then used stop watches to record how long it took to fill the bags with exhaust gases. They also ripped open the bags and smelled the formerly trapped air.

Krasilovsky had prepped the students before they went outside.

"What do we know about car engines?" he asked.

He used his hands balled into fists to remind the students how cylinders move in both in-line, V-8 and horizontal configurations. He also reminded them that their tests weren't measuring carbon dioxide emissions as such, but amounts of exhaust.

"How long do you think it will take to fill up the bag?" Krasilovsky asked as students taped a bag to the Honda Fit exhaust.

"A couple hours," one student said. Another chipped in, "a couple minutes."

Both were wrong.

It took just 36 seconds after school counselor Phipps, a school counselor, turned on the ignition to fill the bag. It took 20 seconds for the GMC Yukon, 16 seconds for the Camry, and 36 seconds for the Volkswagen.

"I was way off on my guesses," Nick Geier, 13, said. "I guessed it would take five minutes. This is pretty cool."

Zoe Hans, 14, added, "I had no idea the hybrid wouldn't fill up at all. It's awesome."

Alex Paul can be contacted at alex.paul@lee.net or by calling 758-9526.