Rubber-Band Rockets. (Investigations)
Hynes, Mary Ellen, Dixon, Juli K., Adams, Thomasenia Lott, Teaching Children Mathematics
The purpose of the "Investigations" department is to provide mathematically rich and inviting contexts in which children and their teachers solve problems, communicate, and reason. Investigations encourage students to make connections among mathematical ideas, as well as connections with contexts outside of mathematics. As students collaborate, experiment, explore, collect data, research various sources, and engage in activities during the investigation, they will have opportunities to represent their mathematical ideas in multiple ways.
Investigations are composed of multiple tasks that collectively promote deep examination of a core topic and question. They are open-ended and often require multiple periods to complete. The following investigation has been adapted from an activity in NCTM's Mission Mathematics: Linking Aerospace and the NCTM Standards, K-6 (1997), a teachers' resource book that presents mathematical problems and tasks that focus on NCTM's Principles and Standards in the context of aerospace activities. The investigation has been enriched by classroom field testing and student and teacher reflections.
Preparing for the Investigation
Most children are interested in rockets and space travel, especially when launches of shuttles are televised. The variables that must be analyzed to produce a successful launch are numerous. Invite your students to explore variables involved with rocket launches, such as the angle of launch, the amount of thrust, and the weight of the rocket. In this investigation, students will use rubber bands to explore how changing a variable affects the distance that the rubber-band rockets travel.
Each launcher can be made using a protractor and a ruler. The ruler is taped to the protractor at the given angle so that the centimeter side of the ruler is on the bottom edge and forms one side of the angle. The ruler should be taped to the protractor in such a way that the straight edge of the protractor may be held flat against the floor, as shown in figure 1. The rubber band is then wrapped around the end of the ruler and stretched along the centimeter side to span the designated centimeter measure in preparation for launch.
The level of mathematical vocabulary used in the investigation depends on the level of the learners. For example, this investigation can be worthwhile for young learners if, instead of discussing angle measures, they are introduced to the idea that the tilt or slant of the ruler will affect the distance traveled. Launchers should be made using 30-degree and 60-degree angles before the start of the investigation for students in grades K-2. Students in grades 3--5 will choose the launch angles that they wish to investigate and will make their own launchers as part of the investigation.
To prepare students for the investigation, ask them, "How can we make a rubber band fly like a rocket?" Some students might say that they would throw the rubber band, but most will agree that "shooting" the rubber band will make it go farther. If students have not had experiences shooting rubber bands, you might want to provide space and time for small groups of students, wearing safety goggles, to experiment with different ways of shooting rubber bands. Have students brainstorm ways in which "farther" could be measured. They may focus on how high the rubber band flies, how far, or for how much time. List suggestions and ideas for making these measurements.
Divide your students into launch teams of five, and assign team roles. One student will be the quality control monitor (to make sure that the group accounts for all variables during the launches), one student will be the rocket launcher, one will be the safety officer, one will be the recorder, and one will measure the distance that the rubber-band rocket travels. Group members will rotate roles with each launch. Launch teams and roles should be assigned before data collection. …