Craft sticks (2 per student)
Rubber bands (2 per student, one thin and one thick)
Straws (2 small pieces per student, about 1-2 cm in length)
Scissors
Tape (optional, for securing the straws)
Worksheet for recording observations and experimenting with sound.Introduction:
Begin with a brief explanation of how sound is produced by vibrations.
Discuss how musical instruments, like harmonicas, create sound through the vibration of air columns and reeds.
Constructing the Homemade Harmonica:
Provide each student with two craft sticks, two small pieces of straw, and two rubber bands.
Instruct students to place one piece of straw near each end of one of the craft sticks.
Lay the second craft stick on top of the first, sandwiching the straw pieces between them.
Wrap a rubber band around one end of the stacked craft sticks, making sure it sits just outside one of the straw pieces. Repeat on the other end with the second rubber band.
Exploring Sound and Vibrations:
Have students blow into the space between the craft sticks and observe the vibrations of the rubber band.
Ask them to note the differences in sound produced by altering the position of the straws, which changes the length of the vibrating rubber band.
Recording Observations:
Provide a worksheet for students to record their observations about how changing the length of the vibrating rubber band affects the pitch.
Have students draw their harmonicas and label the parts.
Discussion and Analysis:
Facilitate a discussion about how the vibrations of the rubber bands create sound waves that travel to the ear.
Discuss how changing the length of the vibrating part of the rubber band changes the pitch of the sound (shorter lengths vibrate faster, producing higher pitches; longer lengths vibrate slower, producing lower pitches).