## Tuesday, February 22, 2011

### Sound: Intensity and Pitch

What is the difference between the INTENSITY and the PITCH of Sound?

 clipart by www.graphicsfactory.com

INTENSITY

The VOLUME of sound is called Intensity.The softness or loudness of sound is its Intensity.
The intensity of sound depends on how strongly an object vibrates. Intensity is measured in decibels.

• Have the children say their names softly and then loudly.
• Ask children to name 3 soft sounds and 3 loud sounds that are in their environment.
• Then have them think of some in between (medium) sounds.
• Children can label 3 columns in their science notebooks and make a list of soft, loud, and in between sounds or you can print out a Free Graphic Organizer for them to use on Learning Workroom's website.
• Children can later get together to read and share their lists.

Go to: Free Worksheets

PITCH

The lowness or highness of sound is its Pitch. The pitch of sound depends on how fast the object vibrates. Something that vibrates slowly makes a low-pitched sound. Something that vibrates very fast makes a high-pitched sound. For example, sounds from a tuba make a low pitch. Sounds produced by a flute make a high pitch. The number of vibrations per second can be counted. This is called frequency.

Have students try this simple experiment to hear the difference between high and low-pitched sounds.

Materials
• empty shoe box or other box without a cover
• rubber bands

Directions
• Put a rubber band around the box. Make the band as slack as possible.
• Tell the students that they will be snapping the rubber band and observing the vibrations while they listen to the sound.
• Ask students to predict if the tightness of looseness of the rubber band will make any difference in the vibrations or pitch of the sound when they snap the band.
• Have students snap the rubber band and listen to its sound as they OBSERVE the band's vibrations.
• Repeat, but make the band as tight as possible.
• Try different rubber bands (vary the width of the bands).
• Have the students record the results of their experiments in their science notebooks.

Explanation: The tighter the band, the faster the vibrations, thus the higher the pitch of sound. The looser the band, the slower the vibrations, thus the lower the pitch of sound.

Video

Here is a Brain Pop Jr. Video on Woodwind Instruments which will introduce the students to the wind instruments and explain more on this topic of  PITCH