Shoebox Guitar

INTRODUCTION

Guitars are musical instruments that produce sounds when their strings are plucked. The guitar can produce a great variety of sounds since the six different strings can be plucked and strummed in innumerable ways. Simple guitars can be made from shoeboxes and rubber bands.

MATERIALS

• 1 shoebox or other small cardboard box
• 4-5 rubber bands with different lengths and widths
• 8-10 metal paper fasteners
• Tape
• Pen

WHAT TO DO

1. Show students a sample shoebox guitar. Pluck the rubber bands one at a time to make different sounds.
2. Let students work in groups of three or four to make guitars.
3. On the lid of the box near the center trace a large circle. Carefully cut the cardboard to remove the circle from the lid. Keep the circle for the next step.
4. Make a bridge for the guitar by folding the outer two thirds of the circle inwards so the edges touch. Tape the top edges together and tape the bridge onto the lid of the shoebox guitar. The bridge should be aligned so that it is near one end of the lid and the long part of the bridge is parallel to the short sides of the lid.
5. Use the pen to make 4 or 5 evenly spaced holes along the each of the short sides of the shoebox lid. Push a paper fastener through each hole and secure them with the heads on the outside of the box lid.
6. Stretch 4 to 5 rubber bands lengthwise across the lid, securing them by tying the ends to the paper fasteners.
7. Stretch the rubber bands over the bridge. If necessary to help the rubber bands stay in place cut small notches in the top of the bridge for the rubber bands to nest in.
8. Place the lid on the shoebox and try out the new guitar.
9. Notice the different sounds that can be made by using rubber bands of various thicknesses or by tightening the rubber bands that are already attached.

QUESTIONS

1. How are the sounds being produced?
2. Why are the sounds of the various bands different?

SUMMARY

Plucking the rubber bands on the shoebox guitar causes them to vibrate. This vibration in turn produces sounds. The pitch of the sound will vary depending on the thickness and length of the rubber band. In general, the thicker the rubber band, the lower the pitch and the longer the rubber band, the lower the pitch. This is because thick rubber bands have more mass than thin ones and long rubber have more mass than short ones. The higher the mass, the slower the rubber band will vibrate. Slow vibrations produce low pitches or frequencies, and fast vibrations produce high pitches or frequencies.

SOURCE

"Teaching Physics with TOYS: Activities for Grades K-9." Taylor, Poth, & Portman, Terrific Science Press: Middletown, 1995, p.89.

© S. Olesik, WOW Project, Ohio State University, 2000.