The Brown Bag STEM Challenge- Hovercrafts

In keeping with the theme of teaching STEM concepts through simple projects whose supplies fit into a brown paper bag (ok, with one or two exceptions ,but you get the idea...), this week, we're designing hovercrafts.  With just a few easy-to-find items, (and a bit of adult supervision for this one) students can construct hovercrafts to learn about forces, motion, friction,and variables.

Materials:

• Compact Discs (will be destroyed) or small diameter plastic plates
• Balloons, round
• 2-liter bottles with caps
• Hacksaw
• Drill
• Binder clips
• Hot Glue Gun and glue sticks

The teacher will need to complete the following prior to the lesson (or, depending on grade level, allow students to complete these steps themselves with adult supervision).

1. First, screw the cap onto the bottle.
2. Using the hacksaw, cut off the top of the bottle at the neck (leaving enough room for students to later stretch a balloon over it).
3. Drill holes in the cap. The holes should be the same in size, but should be different in number in each cap as students will compare their results with those of other teams.

Also, if enough old CDs cannot be found, small diameter plastic plates can be used as a substitute.  If this is done,  use a hole punch or other method to punch a couple of holes in the center.

Once the bottles have been cut and the caps have been drilled, students may begin building their hovercrafts. (The remainder of the bottles will not be used for this project.) Adult supervision may be needed to help with the glue gun.

In groups of 4-5, students can work to build their hovercrafts:

• Screw the cap into the neck. Then,glue the cap to the CD, centering the holes in the cap with the center hole of the CD. Be sure to get a good seal with the glue without covering any of the holes.
• Once the hot glue has dried, students should carefully unscrew the neck. Next, blow up the balloon to the desired fullness and attach the binder clip to hold the air in. Then, stretch the neck of the balloon over the neck of the bottle leaving the threads exposed.
• Last, screw the neck of the bottle to its cap (attached to the CD). When ready to test, release the binder clip and give the CD a small push.

With the hovercrafts built, students can experiment with the friction on different surfaces and also with the number of holes in each cap.


So, what did we learn?
National Science Standards: Abilities necessary to do scientific inquiry, understanding about scientific inquiry, properties of objects and materials, position and motion of objects, motions and forces, transfer of energy, abilities of technological design, understanding science and technology, science as a human endeavor.

NCTM Standards: Understand measurable attributes of objects and the units, systems, and processes of measurement, apply appropriate techniques, tools, and formulas to determine measurements, Formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them, develop and evaluate inferences and predictions that are based on data, build new mathematical knowledge through problem solving, Solve problems that arise in mathematics and other contexts, Apply and adapt a variety of appropriate strategies to solve problems, monitor and reflect on the process of mathematical problem solving, communicate mathematical thinking coherently and clearly to peers, teachers, and others, create and use representations to organize, record, and communicate mathematical ideas.

Other STEM skills: Communication, critical thinking, problem solving, observation, collaboration, data recording, data analysis, teamwork, practice identifying dependent and independent variables, and controls/constants.