The hammered dulcimer is a string instrument with ancient roots. Unlike a guitar, however, the strings are played by hitting them with a small hammer which, in my opinion, is far more fun! Now you can build your own four-string hammered dulcimer and easily redesign your tune by moving the cups to different positions.
DESIGN CHALLENGE
- Build a dulcimer that has four different and nice-sounding tones.
TOOLS AND MATERIALS
- Two pieces of 7″ × 10″ (18 × 25 cm) corrugated cardboard
- Scissors
- Masking tape
- Toilet paper tube
- 12 oz (350 ml) paper cups
- 1⁄8″ × 7″ (3 mm × 18 cm) rubber bands (size 117B)
- Durable plastic straws
Material substitutions
If you don’t have long rubber bands, you can make a smaller dulcimer with smaller rubber bands, cups, and cardboard.
PREP
Cut the cardboard.
An adult may need to help cut two pieces of cardboard into 7″ × 10″ (18 × 25 cm)
rectangles. For extra strength, make sure the corrugations are running lengthwise,
as shown in step 1.
1) Stack the two pieces of cardboard and tape them together in at least four places. This will help prevent the cardboard from bending under the tension of the rubber bands.
2. Attach a toilet paper tube for a handle. Use a plus-sign-shaped taping technique for extra strength: Place a piece of tape that connects the tube to the cardboard, then place another piece of tape across the first one!
3. Rubber bands need space to vibrate. Wrap two rubber bands around the long side of the cardboard. Lift one rubber band at a time and put a cup underneath.
4. Play your dulcimer by swiftly tapping the rubber bands with a straw. Tap each of the four rubber bands and listen to the different tones it makes.
MINDSET: BE REFLECTIVE
5. Reflect by taking the time to notice which tones sound too similar or don’t sound very nice, and change the cup position accordingly. Ask yourself: What kind of tones do long rubber band spans make? Low notes or high notes?
What kind of tones do short rubber band spans make?
What happens if two rubber band spans have similar lengths?
PROCESS: REDESIGN
6. Remember that your design challenge is to create four different tones that sound good. To change the tones, you need to change the length of the stretched-out rubber band spans: Just move the cups to different spots, and then play again.
7. Now redesign again!. Try taping two straws onto the cardboard so the cups are tilted to the side, then play again. What do you notice?
KNOWLEDGE: CONCEPTS AND FACTS
When the cup is tipped to the side, you might find that your dulcimer is much louder. Why? To figure that out, first, we need to know how sound works. Sound is just the air around us vibrating in different ways. Think of dropping a pebble into a puddle: You see the ripples spread across the surface. Sound is similar. For example, when you talk, you are making the air around you ripple with little sound waves. If the same kind of sound waves bump into each other, they become louder. This is called resonance. The cup acts as a resonator: When you hit the strings, the sound waves build up inside the cup. By tilting the cup on its side, you let that resonant, built-up sound escape, which makes your dulcimer louder!