Wave Motion

Susan Frazier                  Fort Dearborn Elementary
                               9025 S. Throop
                               Chicago, Il. 60628
                               312-535-2680
  
Objectives:

Adaptable to grades 1 to 12                                         
                  
The student will be able to:              

1) Identify the frequency, amplitude and phase of a wave.
2) Identify and explain the difference between a transverse and longitudinal 
   wave. 
3) Relate the concept of vibration to frequency and pitch.

Materials needed:

ring stand, cone-shaped cup, string, slinky, springs and ropes (two meters 
long), shoe box, rubber band, paper clips, coffee can, match, ripple tank, 
overhead projector, paper straws, rice crispies, can with top covered with a 
balloon, salt, piece of cloth, baster 

Strategy:

Hang a cup filled with salt, with a hole in the bottom, from a ring stand.

Pull the cup and allow it to swing back and forth over construction paper.

Notice the straight line made by the salt streaming from the end of the cone.

Then, pull the construction paper along the table and let the pendulum continue 
to swing.  Notice the formation of a wave made by the flowing salt.  Have 
students form groups to experience activities on wave motion. 
 
Activities:

1) Shout (do not blow) at the top of a can covered with a balloon with rice
   crispies on top.  (vibration)

2) Pluck a rubber band which is lined with paper clips and stretched across a
   shoe box.  (transverse wave)

3) Hit a coffee can filled with smoke.  (longitudinal wave)

4) Use a slinky, rope or springs to form longitudinal or transverse waves.

5) Make waves in a ripple tank placed on the overhead projector to produce
   circular waves.  (transverse)  Place objects in the water to show that the
   wave moves, but the objects do not.  Also, place a wooden block in the water
   to show incident and reflected waves.

6) Form a human wave by having ten people stand in a line, largest to smallest, 
   with arms locked together, and pull the last person sideways.  
   (longitudinal wave)  Then pull the last person forward.  (transverse wave)  
   In both cases, the waves will be reflected back along the line. 

7) Form standing waves by tying a rope to a fixed object and moving the rope up 
   and down.  (incident and reflected wave) 

8) Form a standing wave by connecting one end of a string to a timer and placing 
   the other end over a pulley.  Connect weights to the end of the string 
   hanging over the pulley.  (170 gm)  Show a wave in phase and out of phase by 
   using a rope.  Have students put their fingers on the vibrating string to 
   locate the nodes and see that the wave is out of phase. 

9) Relate vibration to frequency and pitch of instruments.
   a. Slower vibration causes a lower pitch as shown by scratching a cloth 
      slowly, then faster to get a higher pitch.
   b. Blow into a baster and notice the change in pitch caused by squeezing 
      the end of the baster to change the level of water in the baster.
   c. Make a straw instrument by cutting the tip of the straw on each side
      and blowing into the straw while cutting the bottom of the straw at
      the same time.  Notice the change in pitch.

Culminating Activity:

Make chicken pluckers by putting a hole in the bottom of a paper cup,
pulling a string through and tying it on the inside of the cup.  (Attach
a paper clip to the string inside.)  Pull along the outside string with a 
wet paper towel to produce a loud squawking sound.