The Eggs-Prize

How do you get a water rocket made of a plastic soda bottle to fly 100 feet in the air?

Then, how do you keep the egg “payload” from breaking when the rocket comes back to earth?

These are just a couple of the problems facing a group of sixth and seventh graders at McKinley Classical Junior Academy. They are taking part in an Eggs-Prize science project. 

The after-school project is sponsored by the XPRIZE Foundation in St. Louis. That’s the group which has offered a $10 million prize to the inventors of a new type of low-cost vehicle for repeated, sub-orbital space travel. 

The prize-winning vehicle has to be able to carry at least three people on flights on two consecutive weeks.

The Eggs-Prize rocket project for kids has similar goals. The kids are to invent a low-cost rocket that can reach a certain height, return to earth safely and be reusable. 

The sponsors also want young people to start understanding the process of scientific invention. They also want kids to be thinking about the next generation of space vehicles. 

Eleven-year-old Becky Smith had a taste of working with rockets last summer. She took part in a rocket class for kids at Meramec Community College. 

The sixth grader said, “I thought the McKinley class would be like that. But, I found out we were going to use water rockets here. But, it turned out cool anyway.”

At a recent session, Becky was building a nose-cone to hold parachutes that would slow the rocket’s return to earth. But, she said she hasn’t figured out how to trigger the release of the parachutes at the top of the rocket’s flight. 

She’s also worried about the extra weight of the nose-cone. That might keep the rocket from getting to the 100-foot height that’s needed. 

Becky and other kids already have test-fired the rockets to see which mixture of water and air get the most height. Most of them found putting less water and more pressurized air worked best. 

Eleven-year-old Nicholas Moore used cardboard fins on his bottle rocket to keep it going straight up. “The fins helped it stay steady but the rocket didn’t go up far enough. Then, I took the fins off and used less water. It went higher but it tumbled,” he said. 

Twelve-year-old Clifford Sykes is putting a pointed cone on the top of his rocket to cut the air better when the rocket is launched. He’s also looking at ways to slow the descent of the rocket. 

“I’ve been thinking of putting a shishkabob stick in the nose so it would stick in the ground when it comes down. But, I’m having doubts on whether I can make the rocket come straight down,” he said.

Eleven-year-old Victoria Taylor is thinking about using both parachutes and lots of packing in the nose-cone to cushion the egg “payload” when it comes down. But, she doesn’t know yet how to keep the plastic-bag parachutes from filling up while the rocket is going up. That would cut the height of the launch.

Teacher David Epperson said that balancing answers to all these different questions is part of the scientific experimenting process. He said the Eggs-Prize exercise will help the kids understand how real scientists come up with answers. 

He said, first, the scientists come up with an idea. Then, they make a design and do testing. After that, they often have to re-think their idea and design. That’s because the first thing doesn’t work exactly right. 

The McKinley kids have to pay attention to costs. They are building their rockets from materials that are available in the classroom. The materials include plastic bottles, cardboard, plastic bags, duct tape and other scrap.

Epperson has provided a homemade launching device. It includes a metal base with a locking collar and an electric air pump. Air is pumped into the soda bottle that is partially filled with water. 

When the air pressure is at the right level, the collar on the launch pad is pulled. The rocket is then launched. The kids have a good idea about the proper mixture of water and air needed for best results. 

They’re working on how to slow the descent of the empty rocket with its egg “payload.”

They’re also considering an umbrella made of soda straws that would be folded when the rocket went up. It would open on the way down. 

Teacher Epperson even called his son, who is a helicopter pilot, to see if he had any ideas. Helicopter propellers act as sort of a parachute to slow descent if the plane loses power. But, the kids weren’t sure that would work for their rockets.

The kids hope to have all their experiments done by the end of this semester. Then, they’ll have a joint launch to test which of them invented the rocket that goes up far enough and brings the egg back to earth unbroken.

They have to make their rockets sturdy enough so they can have two successful launches and reentry with the same rocket.