Separate a small matchbox into its two parts. Apply glue along half of each side of the tray, and push the tray halfway into the frame, and let dry.
Cut a small cardboard trapezoid for the bridge, and notch the top in four places. Glue the bridge upright on top of the matchbox, and let it dry. For strings, stretch four rubber bands of various sizes around the matchbox, fitting them into the notches of the bridge. For strumming, buy a guitar pick from a music store.
Discuss: What happens to the note frequency when the width of the rubber band increases?
Quiz: Which instrument is closest to human voice?