Physics of Sound
Investigation 2
Part 1
Vibration and Pitch
Students observe the vibration frequency of a tongue depressor and door fiddle to discover that things have a higher pitch when they vibrate fast.
3. Lesson set up and Management
Wave Behavior: Describe experiences with sound, for example, vibrations, echoes, and pitch. (PC01 1.1.3)
Sound originates from vibrating sources.
Pitch is how high or low a sound is.
Pitch can be changed by changing the length or tension of the object
vibrating at the sound source.
3. Lesson set up and Management
Materials:
You will need your Investigation 2 assessment chart to record your observations of student explorations.
Be sure to find the tongue depressors in your kit. They are wider than the craft sticks.
You will also need to set up the door fiddle. This time you will use it to demonstrate different pitches. It is fun to create different pitches and ask the students what they notice.
Practice with the tone generator and the beans to make sure there is enough power in the batteries. Let the students make predictions before you demonstrate.
Student Management:
Since these activities are teacher guided they are much easier to manage.
When doing the tone generator demonstration be sure to let the students make predictions before you demonstrate.
In these interesting series of investigations be sure to keep in mind that
the objective will be for the students to determine that faster vibrating
objects create high pitches and slower vibrating objects create low pitches.
Remembering that will help you guide the students toward this knowledge as
they explore these fascinating and entertaining materials.
You may want to teach volume on a different day than you teach pitch. Some
students have difficulty keeping these concepts separate.
The tone generator will be helpful in teaching the difference between volume
and pitch. Volume is determined by the amplitude of the vibrations. Larger
amplitudes create louder sounds. Your students should notice that the louder
the volume on the tone generator, the higher the beans "jump". Having the
students feel their throats as they keep the same pitch and increase the
volume can be helpful in clarifying this concept.
Don't skip the activity where students stand next to their desk and move up
and down with the sound from the tone generator. This will be very helpful
now and later.
Reading:
Have the FOSS science stories or other non-fiction readings ready but do not let students read them until they have had the opportunity to do their explorations.