Bellview students test Newton's theory with their 'rockets'
Isaac Newton’s third law of motion declares that for every action, there is an equal and opposite reaction — or, as Bellview Elementary fifth-grader Cayden Ellis puts it, “When something goes into something and gets stuck, it has to force it back out the other side.”
Ellis and his fellow classmates put that law to the test in the halls of Bellview on Thursday afternoon by lining up their balloon-powered rocket cars along a masking tape starting line and letting them go. The goal was to build a rocket that would travel as far as possible and record the outcome.
The students were tasked with assembling their rockets from the materials supplied, with the only variable being the size and placement of the tires. It was part of the school’s engineering and design curriculum, required in part to meet Common Core state standards.
“We talked a little bit about it, about which way is the force going from the balloon and we talked about Newton’s law,” Bellview science coordinator Ginny Sagal said. “And they all love doing it. All kids love doing hands-on science projects, that’s just what they love.”
During the race, giggles and shrieks echoed through the halls as the tiny, wobbly cars built mostly of Styrofoam and straws darted — or in many cases fishtailed — across the linoleum, one at a time.
Each student was supplied with Styrofoam, two small plastic stirrer straws, one flexi straw, a balloon, masking tape and an illustrated instruction sheet that laid out step-by-step how to build the car. The quality of construction varied dramatically from car to car, as did the wheel size. Students also had the option of using three, four or six wheels, decisions which affected the rocket’s mass and weight distribution.
“Generally, heavy rocket racers do less well than lighter racers,” the instruction packet explained. “However, very small racers are limited by other factors. Vehicles with short wheel bases tend to circle or partially lift off the floor. Balance becomes a problem.”
A 1,000-centimeter runway was measured and marked every 100 centimeters, but its length seemed a tad optimistic as many of the racers spun out at the starting line. Unevenly sanded wheels and lopsided construction were the main culprits. Still others chugged along as straight as could be expected, which was about as straight as a real car changes lanes.
Every once in a while a rocket would bolt out of the gate and everybody would stop and watch. One released by a girl in a gray T-shirt seemed destined to set a record. “Whoa, whoa, whoa, whoa, whoa,” a boy gasped, but the car’s propulsion abruptly fizzled out.
Cooper Rathbun said he enjoyed the project, even if he didn’t get the result he was hoping for.
“So our teacher, he pushed against the wall and said there has to be an opposite reaction or he wouldn’t be able to push against the wall,” Rathbun said.
Rathbun’s car, which employed tiny front wheels and triple-the-size rear wheels, traveled 550 centimeters — not too shabby, but well short of Ellis’ record of 800 centimeters.
When asked how he could have improved his design, Rathbun laughed.
“I don’t know,” he said. “Everything really.”
Ellis decided to construct a much more balanced rocket car, cutting out front wheels that were only slightly smaller than those in the rear. That proved to be a much more sound design when his rocket — the inflated pink balloon in front and the straw shooting air out the back — smoothly cruised past the previous record of 600 centimeters.
Ellis let his rocket go and walked behind it as it first steered toward a wall on the left before righting itself and slowing to a crawl just inside the runway’s imaginary out-of-bound line. The balloon was still half-inflated when it stopped, illustrating friction’s role in the experiment.
“It stopped going,” he said, laying on his belly and blowing toward the car in a desperate effort to squeeze out a few more inches. It was futile.
“It’s not going anywhere,” somebody called out.
After three tries, each student was required to fill out a data sheet and graph their rocket’s attempts by distance traveled. It also asked questions, such as “Describe how your rocket racer ran (straight, curved, circles, stuck, etc.)?” and “Did your racer perform as well as you hoped? Explain why or why not?”
Some of the students, such as Abbey Lambert, coaxed steady improvements by making subtle tweaks. Lambert’s first run went 400 centimeters, her second 500 and her third 600.
“It was kind of going (sideways),” said Lambert, who went the extra mile by coloring her racer pink. “It kind of goes like that because it was heavy on this side, so I could have made the wheels heavier.”
Jordan Cardinal, sporting an Oregon Ducks baseball cap, agreed that the design of the wheels impacted performance, but to him the weight of the wheels wasn’t nearly as important as their placement.
“I didn’t want the wheels too wide because if the wheels are too wide I didn’t think it would go far,” he said, “but evidently, with all the other people that had their wheels wider, theirs went farther.”
When asked if he enjoyed studying science, Cardinal was adamant.
“Yeah,” he said, “because you get to try new, different things.”
Joe Zavala is a reporter for the Ashland Daily Tidings. Reach him at 541-821-0829 or email@example.com.