Explorers Club

After a couple of weeks of wondering whether our rockets would soar or flop, the chance to test them finally came. (See the story "What is this, rocket science?" to see the construction of our rockets at our previous meeting.)

First, though, we had to construct our launchers. Mr. Ramsey had actually already made one as a prototype, and then it was up to the students to use it as a guide to help in making the second one. We wanted two launchers for a couple of reasons: first, firing off two rockets at once would allow everyone twice as many chances to launch their creation; and second, it would give us the chance to have head-to-head height and distance competitions--something guaranteed to get the attention of fourth and fifth graders!

The launchers themselves are fairly simple. They are each made from a single piece of 10 foot, 1/2 inch PVC pipe. This pipe is cut (by an adult wielding a hacksaw) into several lengths: a 4-foot section, a 2-foot section, and a pair of 1-foot sections. The 1-foot lengths are attached (with much wrapping of duct tape) to the "bottom" of the 4-foot piece so that it lays steady and stable on the ground. The 2-foot length is then attached to one end of the 4-foot piece with a 90 degree PVC elbow, so that the 2-foot piece stands up vertically at one end. (Visit the gallery for photos that will literally help in picturing this contraption.) The "seams" where the elbow piece joins the pipes are thoroughly wrapped in duct tape to ensure an air-tight seal.

Finally, at the opposite end of the 4-foot section from where the vertical piece joins, an empty 2-liter pop bottle is fit into place (such a bottle will fit fairly snugly over the end of the half-inch pipe), with this connection also liberally wrapped up in duct tape to give an air-tight seal. The air contained in this empty pop bottle actually provides the "fuel" for our rockets. When one of the elementary rocket engineers compresses the air in the bottle with a good hard stomp, the air has nowhere to go but down the length of the pipe, through the elbow, and up the vertical pipe. Here it will meet a rocket that has been placed over the end of the launcher--with a nice snug fit, since the rockets were made in the first place by wrapping magazine paper around the same diameter pipe as makes up the launcher.

And at last it was time to head outside for the countdown. Launch conditions were mostly cloudy and chilly, but with no threatening weather to force any "holds."

Prior to the first pair of launches, Mr. Ramsey laid down the law in terms of rules: absolutely no one is allowed to approach the launchers except the pair of students who were actually engaged in firing off their rockets. The cellophane tips of the rockets ensure that the landings are soft enough to avoid injury, but at the moment of launch they are propelled at a high enough speed that the "gantry" needs to be clear of spectators.

Mr. Ramsey also slightly misled his team of rocket engineers, by telling them that hopefully a stomp on the bottle would get the rocket to "pop off" the launcher, and that a really effective launch "might even get the rocket to go as high as our heads." With that in mind, the first pair of students stepped up, and on a group countdown they fired off their rockets.

And up the rockets soared--to a ridiculous height, really, considering that they were made of nothing but magazine paper and tape and propelled by nothing but the air from a pop bottle. They were WAY up there, well above the tall trees in front of the school, before flipping over and plummeting back to earth.

The roars of triumph from the student rocket engineers shook the neighborhood as two by two they took their turns at sending their rockets skyward. It naturally became an arms race to see who could send theirs the highest. Some soared straight and true, some were a bit wobbly in flight, some left one or more fins behind as they lifted off, and one rocket was so tight and snug on the launcher that it literally refused to leave the pad (leaving its builder to run back inside to quickly put another one together).

Everyone had several chances to do a launch, and if it wasn't for the cold weather (and the arrival of parents who seemed to think that dinner should be served at some time during the evening), most of the engineers would have cheerfully kept launching until dark. We eventually tilted the launchers so that the vertical pipes were at an angle, giving us the chance to add a distance component to our tests as well as height. The sidewalk running from the school's front door to the street became the new goal, with several small trees serving as strategic barriers to success.

To say that this activity turned out to be a keeper would be an understatement. To see some photos from our launch day, click on the word "Gallery" below.

Gallery

Note: The pop bottle rocket launcher is one of several projects that the Explorers have done that have come from the "Science Toy Maker" web site. There are a number of other projects at this site that would be fun for students to make at home--just don't be surprised if someday we end up doing the same thing in one of our club meetings! Click on the link below to visit the site.

Science Toy Maker Web Site