Explain the concept behind the aerospace racing cars to let your students understand that when you inflate the balloon, the balloon compresses the air. When you release the nozzle, the balloon propels the air from its tiny nozzle. As the air comes out, it produces an equal and opposite force pushing the racer in the opposite direction and the racer shoots down the race track.
To make your balloon-powered car you need to collect Styrofoam food trays from supermarkets, some drinking straws, pins, round balloons and masking tape. You will also need a pencil, scissors, ruler, and meter stick or measuring tape for laying out a race course. Additionally, provide the students with worksheets such as "How to Build an Aerospace Racer" to provide the construction instructions and an aerospace racer data sheet to record the outcome of the experiment.
Issue the students an instruction sheet and explain the activity to the students. Review the procedure for the construction then showcase the techniques of cutting out the racing car parts, putting on the wheels and fixing the straw and the balloon on the racer. Let the students fill out the graphs, after you show them how to use the data sheet, and explain what data they should collect.
Let the students plan how they will arrange the parts of the car before they cut them with the scissors. If you are working with younger students, who could harm themselves with the scissors, you may instruct them to trace the shapes with the sharp-pointed tips of their pens or pencils. If they press the traces deeply, they will manage to remove the pieces from the Styrofoam.
The racing cars will require a race track at least 10 meters in length, which you must help them set on the floor. You can join together several metric tape measures and lay them on the floor which they will use to measure the distance the cars will travel. Instruct your students to measure the distances in intervals of 10cm.
The next activity after constructing the racers involves the actual race. Let one or two students take turns to inflate their balloons and hold the end of the straw with the thumb and the index finger to keep the air inside. Instruct the students to put their racers behind the starting line, let go of the straws and record how far the cars reach along the straight line of the race course.