Exploring Sound: Length Makes a Difference
Summary
In this elementary physics lab, students will begin to explore the relationship between the length of an object and the sound it produces by using a wood or metal ruler.
Learning Goals
This activity is designed for students to discover that the length of a sound-producing object affects the sound of the object. Students may be able to match the note made by the ruler with a note on the piano. Students will develop listening skills as they practice with the rulers. Vocabulary: vibration, pitch, sound
Context for Use
This is a introductory lab activity appropriate for any age students K-12. The actual activity was taken from a middle school level physics textbook, and can be adapted for any age. Depending on how involved you'd like the students to get, the activity can last anywhere from 10 minutes to a few days if the students will be developing a piece of music with the sounds from the vibrating rulers. I plan to use this activity as an introduction to sound, but it could also be used as a final activity. It would be very appropriate for use in a music classroom as well.
Description and Teaching Materials
Each student will be given a wooden ruler and asked to see if they can make different sounds with it. After a few minutes of exploration with the rulers, we will discuss as a class the different ways that sounds can be made with the ruler. If no one has discovered the method of laying the ruler flat on a desk with the free end extending beyond the desk, we'll all try that at this time. I'll have the students gently pull up on and release the free end of the ruler and talk about what they see and hear. We'll then move the ruler to allow more or less length to hang over the edge of the desk and repeat the experiment several times to hear different sounds. We'll also see if we can make the rulers play the notes to familiar songs. This activity is adapted from one in the Glencoe/McGraw-Hill Physical Science textbook, copyright 1999, page 497
Teaching Notes and Tips
The students need to be reminded to be careful with wooden rulers, they might break. Other than that, this is a very easy activity to implement. Our third grade textbook devotes a "whopping" three sentences to sound, so this is an activity I'll use to supplement that to help meet the third grade physical science standard.
Assessment
Students will achieve their learning goals if they can successfully move their ruler to make sounds. The teacher will observe the students as they explore the sound a ruler can make.
Standards
3.II.C.1 Investigation of how sounds are made when objects vibrate