Applied Science - Science and Math (5C) Lab
 OBJECTIVES: Distinguishing different types of sound. Experimenting, recording and interpreting data. VOCABULARY: experiment frequency interpret pitch sound vibrations MATERIALS: tuning forks 6 jars at each station which are the same size nail pencil pen rubber bands Students experiment with tuning forks and sound.
 BACKGROUND: There are two major types of waves, physical waves and electromagnetic waves.  Sound waves are physical because they actually have a physical motion in the surrounding area.  Light is an electromagnetic wave which will be discussed in detail in the 5th grade physics lesson.  Waves represent a mechanism whereby energy is transmitted. Sound is heard because of vibrations.  Vibrations are a disturbance of the air space that mechanically moves the air.  Sound cannot travel in a vacuum because there is no medium.  Sound travels in a push-pull or compressional type of manner.  Introduce the word "pitch."  A pitch is the "highness" or "lowness" of a tone, governed by frequency.  High frequency equals a high pitch sound, while low frequency equals a low pitch sound.   When a rubber band is stretched a little and strummed, it will cause little vibrations and a low pitch.  If you stretch the rubber  band further and strum it, they will have created a higher pitch. PROCEDURE: In this experiment, students will establish that sound needs a medium to be transferred.  Students are asked to see if the sound produced by a tuning fork can be felt or heard by hitting the tuning fork and touching it to the nose, hand, nail, paper, pencil, pen and cup of water.      Students should feel a "tingling" feeling when the tuning fork's tines touch their bodies.  The nose is the most sensitive.  The nail, pencil, and pen will just vibrate.  The papers should give a humming sound.  The vibrating tuning fork sets up vibrations in the water.  The spot where the tuning fork hits the water is similar to the focus of an earthquake or the point where a pebble enters the water.     In the next activity, students are asked to look at 6 similar jars and fill them with different amounts of water.  Different amounts of water in a jar will produce different sounds.  Students should only use a stick or pencil to tap the jars, and then record their findings.  The more liquid in the jar, the lower the pitch.  Have students arrange the jars from lowest to highest pitch.    Students have learned that sound is a physical wave and is transmitted through substances in different ways.