Let’s Discover: Sound Sandwiches

discovermasthead
Kick the winter blues with these homemade musical instruments and the science of sound. Fun and simple to make, these noisemakers are a great way to explore the concept of sound as a vibration.
Materials

Drinking straw
Two large craft sticks/tongue depressors
Two small elastics
One wide elastic
Scissors

sound
Procedure

Stretch the wide elastic around the length of a craft stick so that it lays flat. Remove any twists.
Cut two pieces of the drinking straw, long enough to extend a few centimetres wider than the craft stick on either side
Place one straw piece under the wide elastic and one over the elastic, about 2.5 cm from either end of the craft stick (see photo below).

sound1

Sandwich the other craft stick on top of the straws, holding them together with one hand. Make sure the loose straw does not fall out!
Using your other hand, wrap the small elastics around the ends of the sticks so the straws are held in place. The elastics may need to be wrapped and twisted over multiple times, depending on their size.

sound2
Below are two finished sound sandwiches – top-up on the left, and bottom-up on the right.
 
sound3

Make sure there is a small space between the two craft sticks. The gap is made by the two sandwiched straws. If you cannot see a gap, loosen the small elastics on the ends.

sound4

Hold on to the ends of your sound sandwich, put your lips over the centre, and blow through the gap in the middle!

Your breath passing over and under the wide elastic causes it to vibrate up and down, creating sound. The vibrating elastic is acting like the reed found in some wind instruments.
Try adjusting the straws so they are closer together, or pinching the ends of your sound sandwich tighter. How does this affect the pitch of your sound? Is it higher or lower? By shortening the length of elastic that can vibrate, you make it vibrate faster, creating higher-pitched sounds.
Try building a few sound sandwiches that make different high and low notes, and make some music! For more hands-on activities and fun join us over the March Break. Don’t forget your Sound Sandwich – maybe one of our Interpreters will join you at the Slap Organ for a jam session!
For more great things to discover – visit the Discovery Centre on Barrington Street in Halifax, check out their website  or join them on facebook.

PAINT DAY! WORKSHOP with Shelagh Duffett!

Joseph Howe Drive at Atlantic Superstore intersection – Flashing Traffic Signals