Can you help your grandfather listen to the music that he loves again?
Problem
Grandpa loves reggae music. At least he has for as long as you’ve known
him. (Which is all your life.) Recently, though, he’s started to lose his
hearing, and he absolutely refuses to see a hearing doctor about getting
hearing aids. You’re planning on taking him to a reggae concert for his 76th
birthday, and you want him to be able to enjoy it to the fullest. Over to you!
Your Mission
Using the materials provided, your phone, and the Science Journal app,
you must design and build a hearing aid for your grandfather so he’ll be
able to enjoy the concert.
Instructions
Roll up a piece of cardstock into a 6″ long tube and secure it together
with duct tape. Cut a slot in the tube that will be large enough to allow
a smartphone to fit in it.
Take two paper cups and cut a circle out of the side of each big
enough for the tube. Slide the cups onto the tube and secure them
on with duct tape.
Pick a device to play the sound through. Something with a smaller
speaker such as a smartphone is preferable.
Find a quiet space to test the amplifiers (your teacher will use the
Google Science Journal app on their phone to test).
Place the test phone approximately 4 feet from the amplifier.
Play a sound through the smartphone in the amplifier. We recommend
a 500hz sine wave (can be found on YouTube).
When the sound is playing, press the “Record” button in the Science
Journal app and gather data for 30 seconds to filter out other small
noises that occur during testing.
Use the average value from the 30 second measurement as a metric
of success.
Hint
Think about the horn of a tuba. What shape is it? What do you think that
does to the sound?
How to Test
Pick a device to play the sound through. Something
with a smaller speaker such as a smartphone is preferable.
Show your students the device they are amplifying,
then have them create a passive amplifier using the
materials provided.
Find a quiet space to test the amplifiers.
Download the Science Journal app on your smartphone.
Navigate to the Sensors menu, and select “Sound
intensity (dB).”
Place your phone approximately 4 feet from the sound
source with a student amplifier attached.
Play a sound through your sound source. We recommend
a 500hz sine wave (can be found on YouTube).
With your sound playing, press the “Record” button in
the Science Journal app and gather data for 30 seconds
to filter out other small noises that occur during testing.
Use the average value from the 30 second measurement
as a metric of success.
Example Solution
Cut a small, rectangular slot near the bottom of a paper
cup to accommodate the device creating the test sound.
Bend the pieces of cardstock to match the curvature of
the cup.
Duct tape the cardstock to the exterior of the cup,
extending the walls of the cup upward, making a cone.
Student Hint
Think about the horn of a tuba. What shape is it? What do you
think that does to the sound?
