Materials Included In Kit

Additional Materials Required

Prelab Preparation

Activity A. Modeling Faults

1. Using sharp scissors or a paper cutter, cut each foam sheet into 1¾" x 8½" strips. Three of these strips should be obtained from each foam sheet (see Figure 17).
   {12142_Preparation_Figure_17_View from top of foam sheet}
2. Sort the foam strips so that each student group receives one strip each of four different colors.

Activity B. Elastic Rebound

1. Obtain the sandpaper strip with adhesive backing and cut two 38" pieces.
2. Making sure the workstation table is clean, remove the adhesive backing from one of the 38" pieces and press the sandpaper strip down along one edge of the table (see Figure 9 in the Procedure for Activity B).
3. Repeat step 2 for the second 38" strip of sandpaper. Note: The backing may be saved and pressed back onto the sandpaper strips for storage after the activity.
4. From the remaining strip of sandpaper, cut two 3⅞" x 3" pieces. Remove the backing from each piece and press onto one face of each wood block. Note: Place each block sandpaper-side down at each workstation to ensure good adhesion between the block and the sandpaper.

Activity D. Resonance

1. Obtain the five chenille wires. Cut one wire into two 15-cm pieces.
2. Cut two wires to 25 cm and the other two wires to 20 cm. Discard the shortest pieces.
3. Obtain six plastic foam balls. Gripping one wire near the end, carefully twist the end into a ball. If the wire will not twist into the ball without bending, a small nail may be used to make a hole half way through the plastic ball.
4. Remove the wire from the plastic ball and squeeze a small amount of glue into the hole. Reinsert the wire into the ball.
5. Repeat steps 3–4 for the remaining wires and balls.
6. Obtain a 2" x 6" foam base. Insert the free end of the 25-cm chenille wire into the center of the base, being careful that the end of the wire does not poke through the bottom of the base.
7. Centering the wire width-wise, insert the 20-cm wire one inch from the end of the base.
8. Insert the 15-cm wire one inch from the opposite side of the block, in line with the other two wires (see Figure 18).
   {12142_Preparation_Figure_18}
9. Repeat steps 6–8 for the second foam base.

Safety Precautions

Wear safety glasses when working with rubber bands, the Slinky and the resonance apparatus. Take care not to suddenly release a stretched Slinky. The spring may snap back rapidly, which may cause personal injury or damage to the Slinky. Remind students to wash their hands thoroughly with soap and water before leaving the laboratory

Lab Hints

• For best results, set up two stations for each activity throughout the lab. This will allow 8 groups of students to rotate through four activity stations in a 45- to 50-minute lab period. A double lab period (two 45- to 50-minute class periods) will allow time for both a review of earthquake concepts before the lab and for a collaborative class discussion after lab.
• Each activity is a self-contained unit and may be completed in any order. Students should need only 8–10 minutes per station—keep the pace fairly brisk to avoid dawdling. Post-Lab Questions and the crossword puzzle clues may be answered during downtime between stations.
• Prelab Preparation is an essential component of lab safety, and it is also critical for success in the lab. (Standing in front of the lab station is not a good time for students to be reading the activity for the first time.) Having students complete the written prelab assignment and reviewing the safety precautions for each activity will help teachers ensure that students are prepared for and can work safely in the lab.
• Enough materials are included for Activity A so each student group may make its own fault model. These may be used as a reference if more time is needed in order to complete the sketches and answer the questions.
• The rubber bands in Activity B may stretch out after repeated use. Provide fresh rubber bands for each group.
• The sandpaper will become smoother after repeated use and may need to be replaced. Sandpaper belts designed for belt sanders may be obtained from local hardware or home improvement stores. These may be cut and taped onto the work table.

Teacher Tips

• This is a great activity to use during a study of plate tectonics and earthquakes or a study of forces and energy.
• Visit the U.S. Geological Survey website http://earthquake.usgs.gov/ (accessed May 2010) to learn more about earthquake predictability and to see where earthquakes have occurred recently around the globe.
• Students may use a computer spreadsheet program to make the optional graph for Activity B.
• The crossword puzzle was made using online crossword puzzle software found at www.variety-games.com/CW/ (accessed May 2010).
• Use Flinn Scientific’s Find the Epicenter—Student Activity Kit (Catalog No. AP7266) and Strike-Slip Fault Activity Model (Catalog No. AP7374) to further explore earthquakes.

Answers to Prelab Questions

Activity A. Modeling Faults

1. Describe the forces that are responsible for divergent plate boundaries and the type of fault that results.

   Divergent plate boundaries are subject to tension forces, resulting in a normal fault.

2. Describe the forces that are responsible for convergent plate boundaries and the type of fault that results.

   Convergent plate boundaries are subject to compression forces, resulting in a reverse fault.

3. How is a strike-slip fault different than a normal or reverse fault?

   Strike-slip faults have little upward or downward movement of the plate boundaries as compared to reverse and normal faults.

Activity B. Elastic Rebound

1. What does the movement of the chain of rubber bands represent? What does the block of wood represent?

   The chain of rubber bands represents the movement of the tectonic plate. The block of wood represents the fault.

2. What safety precautions are necessary for this activity?

   Wear safety glasses for protection from eye injury in case a rubber band breaks during the activity.

Activity C. Seismic Waves

1. Compare and contrast primary and secondary waves.

   Primary waves are compression waves in which the rocks move back and forth in the same direction the wave travels. Secondary waves are transverse waves in which the rocks move perpendicular to the direction of the wave. P-waves travel faster than S-waves. Both originate at the focus of an earthquake and travel through the body of the Earth.

2. What safety precautions are necessary when working with the Slinky?

   Wear safety glasses and take care not to suddenly release a stretched Slinky. The spring may snap back rapidly, which may cause personal injury or damage to the Slinky.

Activity D. Resonance

1. Define the following terms.
   1. Frequency—The number of back-and-forth vibrations per second
   2. Resonance—Occurs when vibrations are amplified by waves of the same frequency
2. Why should safety glasses be worn during this activity?

   Safety glasses should be worn to protect the eyes in case the plastic balls or the wires shake loose.

Sample Data

Activity A. Modeling Faults

Activity B. Elastic Rebound Activity C. Seismic Waves Activity D. Resonance

Answers to Questions

Activity A. Modeling Faults

1. What is the relationship between faults and earthquakes?

   Most earthquakes occur along tectonic plate boundaries. Faults are created when plate boundaries are subjected to forces and rock movement occurs.

2. What happened to the river as the land sections shifted along the strike-slip fault? How would this affect the course of the river?

   The river’s path was altered when the strike-slip movement occurred at the fault. Eventually the river may wander and run a new course and a portion of the original path of the river may dry up.

3. What determines whether a strike-slip fault is right-lateral or left-lateral? What type of strike-slip fault was formed in step 14?

   The direction the portion of rock is displaced on the opposite side of the fault from the viewer determines whether the strike-slip fault is right- or left-lateral. The sample strike-slip fault is right-lateral.

Activity B. Elastic Rebound

1. Determine how far the block moved for each slippage event and fill in the third column of the data table for Distance Block Slipped. For example, if the starting position for the block was 10 cm, and when the block slipped the first time it came to rest at 15 cm, the block slipped 5 cm. This is recorded in the second row of the third column for block slippage 1.

   See Sample Data Table B.

2. Determine how far the rubber band chain was stretched for each slippage event and fill in the last column of the data table. For example, if the pencil point started at 35 cm and had been moved to 45 cm when the block slipped for the first time, the rubber band chain stretched 10 cm. This is recorded in the second row of the last column for block slippage 1.

   See Sample Data Table

3. What caused the block to slip? Describe the forces involved and the transfer of energy that took place from one slippage event to the next.

   The motion of the pencil stretched the chain of rubber bands, increasing their elastic potential energy. The last rubber band connected to the block exerted a force on the block, but the force of friction between the block and the sandpaper strip opposed any forward motion of the block. Eventually the rubber band chain exerted enough force on the block to overcome the force of friction and the block slipped forward with kinetic energy. The kinetic energy of the block was converted to heat energy as friction opposed its forward motion and the block stopped. Some energy was also transferred to the air and table as vibrations and waves.

4. For each block slippage event, compare the distance the rubber band chain stretched to the corresponding distance the block slipped. Describe any relationship between the two distances. Optional: Create a graph that shows the stretch of the rubber bands compared to the distance the block slipped.

   In general, the longer the rubber band chain is stretched, the greater the slippage of the block. However, this is not always the case. For example, one time the lead rubber band moved 5 cm and the block slipped 2.9 cm and another 5-cm stretch of the rubber band resulted in a 7.1-cm slip of the block.

   {12142_Answers_Figure_19}
5. How is this model similar to the elastic rebound cycle of faults created by the Earth’s tectonic plate movement? How is it different?

   The rubber band chain moved at a relatively constant slow speed, much like the Earth’s tectonic plates. As the force of friction was exceeded, the block moved suddenly and tension on the rubber bands relaxed momentarily. In a similar way, rocks along a fault shift suddenly and an earthquake occurs. The forces involved with tectonic plate movement are more complex and the energy comes from the internal heat of the earth. The force of friction within a fault comes from the plates grinding against each other, and the rocks along a fault store energy until they suddenly shift or break. In the model, the rubber bands were stretched, storing energy until they pulled the wood block with enough force to cause it to slip.

6. How does this activity explain the unpredictability of earthquake occurrence and magnitude? How are seismologists able to forecast the probability that an earthquake is likely to occur and how great it might be?

   In this model, it was impossible to predict exactly when and how much the block would slip. However, as tension increased with each centimeter-stretch of the rubber bands, the likelihood of a greater slippage of the block also increased. Once a slippage occurred, the chance of another large slippage occurring in the near future decreased. The more time that has elapsed since an earthquake has occurred along an active fault, the likelihood of a larger magnitude earthquake increases.

Activity C. Seismic Waves

1. How does the string show that the coils of the spring do not move from one end of the string to the other but that energy is being transferred along the spring?

   The string does not move along the spring with the wave. Since the string is displaced from its original position and moves back again as the wave passes, kinetic energy is present in the spring.

2. How does the greater displacement of the spring relate to the magnitude of an earthquake?

   The greater displacement of the spring generated more energy than a smaller displacement. A large sudden displacement of rocks along a fault would also generate much energy, resulting in an earthquake with a higher magnitude than would a smaller displacement of rocks.

Activity D. Resonance

1. Summarize the observed relationship between the resonance frequency and the length of the wire.

   The longer the wire the lower the frequency at which the wire resonates.

2. Based on your observations, do any of the wires share the same natural frequency? Give reasons for your answer.

   None of the wires shared the same natural frequency since none resonated at the same time.

3. Based on your observations, explain why a high percentage of the 6- to 12-story buildings described in the Activity D Background section suffered considerable damage during the 1985 Mexico earthquake, while shorter and taller buildings did not.

   The middle-sized buildings must have had the same natural frequency as the ground shaking during the earthquake. This caused the 6- to 12-story buildings to resonate. The shorter buildings would require a higher frequency and the tallest buildings would require a much lower frequency to resonate.

Teacher Handouts

12142_Teacher1.pdf

References

USGS Earthquake Hazards Program. http://earthquake.usgs.gov/ (accessed May, 2010).

Introduction

Much has been learned about what causes earthquakes and how to reduce the aftermath of their destructive forces on human lives and property. However, in spite of modern technology and over a century of research, seismologists are still unable to precisely predict when an earthquake will occur or how strong it will be. Explore what causes earthquakes, why they are so unpredictable and investigate factors that impact the effects of seismic activity.

Concepts

• Earthquakes
• Elastic rebound
• Faults
• Seismic waves
• Resonance

Background

For centuries, earthquakes have both fascinated and frightened. In ancient times Poseidon, the “god of the sea” of Greek mythology was believed to possess the power of “earth-shaker.” Seismologists, scientists who study earthquakes, have provided us with understanding of the physical forces and geological conditions involved in earthquakes. Even so, earthquakes occur with little or no warning. On December 26, 2004, an undersea earthquake off the northern coast of Sumatra, Indonesia triggered a tsunami that resulted in more casualties than any tsunami in recorded history—more than 225,000 people were killed or were missing and presumed dead. As our understanding of the underlying forces that cause earthquakes increases, so will our ability to save lives.

Activity A. Modeling Faults
Most earthquakes occur along tectonic plate boundaries. These boundaries create cracks or faults in the Earth’s crust. At divergent plate boundaries, or areas where plates are spreading apart, rocks are subjected to stretching forces known as tension. Tension can pull apart rocks and create normal faults. A normal fault occurs when a portion of rock drops downward relative to another portion of rock (see Figure 1). Normal faults are the result of the expansion of the Earth’s crust.

Reverse faults occur when one portion of rock is pressed upwards relative to another portion of rock (see Figure 2). Compression forces at convergent plates (areas where plates are being pushed together) are responsible for reverse faults. The compression pushes on rocks causing them to bend and break and move along a reverse fault surface. A transform or strike-slip fault occurs where two portions of rock slide past one another without much upward or downward movement (see Figure 3). Rocks exposed to strike-slip faults are subject to shearing. Shearing forces push on rocks from different directions. As the rocks move past each other, their surfaces rub against each other and cause a large amount of strain or twisting. In these areas stress is increased, and as the rocks reach their elastic limit, they break and an earthquake results. Strike-slip faults may be categorized as either left-lateral or right-lateral. If the portion of rock on the opposite side of the fault from the viewer is displaced to the left, a left-lateral strike-slip fault results, and when the rock is displaced to the righ2830%;" data-type="center">{12142_Background_Figure_3_Strike-slip fault} Activity B. Elastic Rebound
The rocky plates that make up the Earth’s crust are in constant motion. The interactions of these plates create faults, or cracks, that offset the Earth’s crust. Continuous movement of the plates builds up pressure until the rocks along a fault shift or break, releasing energy that causes an earthquake. The cycle of gradual build-up and release of stress along a fault is known as the elastic rebound theory, first proposed by American geologist Henry Fielding Reid (1859–1944). Reid was part of a task force commissioned by the state of California to investigate the 1906 San Francisco earthquake. Reid closely examined the surface ground displacement caused by the 1906 earthquake. By investigating data from surveying records, he realized that some ground displacement occurred away from the fault before the earthquake. He concluded that stress built up slowly along the fault until the strain was suddenly released by slippage of the fault. Reid compared the energy released by the rebound of the fault to that of a rubber band breaking when it was stretched too far. Even though the theory of continental drift was proposed by German scientist Alfred Wegener (1880–1930) shortly after Reid’s theory, it would be more than a half century later before the movement of the Earth’s plates would be connected to earthquakes along fault lines.

Activity C. Seismic Waves
When the rocks along a fault shift or break, energy is released that causes an earthquake. This is similar to what happens when you snap your fingers. The force between your fingers increases until the fingers suddenly slide past each other. The “snap” is caused by the release of energy in the form of sound waves. Energy from an earthquake is transmitted through the Earth in the form of vibrations known as seismic waves (from the Greek word seismos, to shake or quake). Seismologists determine the magnitude of an earthquake—the energy released at the source of the earthquake—by studying seismograms which detect and record the vibrations of seismic waves. Two types of seismic waves travel outward from the focus (origin within the Earth) of an earthquake. The primary wave, or P-wave, is a compression wave that forces rock to compress and expand in the same direction the wave travels. P-waves travel through the Earth at an average speed of about 5 kilometers per second. Secondary waves travel at a slower rate, averaging about 3 km per second. Secondary or S-waves are transverse waves in which the vibrations displace matter perpendicular to the direction the wave is moving.

Activity D. Resonance
An earthquake with a magnitude of 8.5 struck Mexico on September 19, 1985. Mexico City, 250 miles from the epicenter, sustained considerable damage. A high percentage of 6- to 12-story buildings suffered damage while a very small number of one- and two-story buildings were damaged. A 48-story building experienced only minor damage—a few broken windows. While many variables affect the amount of damage a building suffers as a result of an earthquake, the natural frequency of a building is a contributing factor.

All objects including buildings have a natural frequency or set of natural frequencies at which they vibrate. The frequency of a vibration is the number of back and forth cycles (oscillations) that occur per second. The natural frequency of an object depends on its size and composition. Seismic waves traveling through the ground cause the ground to vibrate at its natural frequency. If the natural frequency of the ground matches the natural frequency of a structure built on that ground, then the motion of the building will be amplified, resulting in a vigorous oscillating movement. This higher amplitude oscillation is known as resonance. A common occurrence of resonance is a child being pushed on a swing. If the push is given in rhythm with the natural frequency of the swing, the child will swing higher and higher.

Experiment Overview

The purpose of this activity-stations lab is to use models to investigate various aspects of earthquakes. Four mini-lab stations are set up around the classroom. Each activity focuses on a particular concept associated with the geological formations, physical forces, and energy of earthquakes. The activities may be completed in any order.

1. Activity A. Modeling Faults
2. Activity B. Elastic Rebound
3. Activity C. Seismic Waves
4. Activity D. Resonance

Materials

Prelab Questions

Activity A. Modeling Faults 
Read through the Background section for Activity A.

1. Describe the forces that are responsible for divergent plate boundaries and the type of fault that results.
2. Describe the forces that are responsible for convergent plate boundaries and the type of fault that results.
3. How is a strike-slip fault different than a normal or reverse fault?

Activity B. Elastic Rebound
Read through the Background, Safety Precautions and Procedure sections for Activity B.

1. What does the movement of the chain of rubber bands represent? What does the block of wood represent?
2. What safety precautions are necessary for this activity?

Activity C. Seismic Waves
Read through the Background and Safety Precautions sections for Activity C.

1. Compare and contrast primary and secondary waves.
2. What safety precautions are necessary when working with the Slinky?

Activity D. Resonance
Read through the Background and Safety Precautions sections for Activity D.

1. Define the following terms.
   1. Frequency
   2. Resonance
2. Why should safety glasses be worn during this activity?

Safety Precautions

Wear safety glasses for protection from eye injury in case a rubber band breaks during the activity. Take care not to suddenly release a stretched Slinky^®. The spring may snap back rapidly, which may cause personal injury or damage to the Slinky. Do not extend the Slinky more than 3 meters. While unlikely, vigorous shaking of the apparatus may cause the plastic balls or the wires to shake loose. Please follow all laboratory safety guidelines. Wash hands thoroughly with soap and water before leaving the laboratory. 

Procedure

Activity A. Modeling Faults

1. Obtain four different colored strips of foam. Each strip is 1¾" wide by 8½". long.
2. Stack the foam strips on top of one another (see Figure 4). The stacked strips represent a layered cross section of land, with each color representing a different rock layer.
   {12142_Procedure_Figure_4_Side view}
3. Using a marker, draw two lines down the center of the top strip as shown in Figure 5. These lines represent a river.
   {12142_Procedure_Figure_5_View from top}
4. Using a ruler, measure 2½" from each side of the top of the stacked strips. Use a marker to place a small mark on the top foam strip at these locations (see Figure 6).
   {12142_Procedure_Figure_6}
5. Using scissors, make a diagonal cut starting at the 2½" mark on one side of the top layer as shown in Figure 7. For best results, cut each strip individually. Use the cut piece from the top layer as a guide for the other layers.
   {12142_Procedure_Figure_7_View from top}
6. Repeat step 5 on the other side of the strips as shown in Figure 7. The cuts represent faults in the land.
7. Rubber band each of the three land sections as shown in Figure 8.
   {12142_Procedure_Figure_8_View from top}
8. Place the three land pieces together and lift them slightly above the work surface by grasping the two outer pieces and exerting a slight force inward.
9. Once the three pieces are raised about a half centimeter above the surface, simulate a normal fault by pulling the two outer pieces away from the center piece and observe what happens.
10. Sketch a cross section (side view) of the land pieces as they look from step 9 and record all observations in the Data Table. Note the locations of different layers of rock relative to one another. Label the color of each layer and draw arrows to indicate the movement of the land pieces.
11. Return the three land pieces back together on the work surface.
12. Holding the two outer pieces near the fault lines, exert a force to simulate a reverse fault.
13. Sketch a cross section (side view) of the land pieces as they look from step 12. Describe how you moved the pieces to simulate a reverse fault and record all observations in the data table. Note the locations of different layers of rock relative to one another. Label the color of each layer and draw arrows to indicate the movement of the land pieces.
14. Return the three land pieces back together. Simulate a strike-slip fault with two of the pieces.
15. Sketch a top view of the land pieces as they look from step 14. Include the lines representing the river. Draw arrows to indicate the movement of the land pieces. Describe how you simulated the strike-slip fault and record all observations in the data table.

Activity B. Elastic Rebound

1. Place a meter stick next to the sandpaper strip found at this activity station so the zero mark lines up with the left end of the strip (see Figure 9).
   {12142_Procedure_Figure_9}
2. Obtain seven rubber bands. Attach one rubber band to the screw eye of the wood block by looping one end of the rubber band through the eyehole and then through the other end of the band (see Figure 10). Pull gently to tighten.
   {12142_Procedure_Figure_10}
3. Attach a second rubber band to the first one in the same manner as the first rubber band was attached to the screw eye. Repeat with the remaining five rubber bands in sequence to form a chain.
4. Place the wood block with the sandpaper side down on top of the sandpaper strip so the end opposite the screw eye is at zero.
5. Measure the length of the wood block (not including the screw eye) and record this to the nearest centimeter as the Start for the leading edge of the block in the data table.
6. Position the chain of rubber bands attached to the wood block in a straight line. Extend the chain without causing any tension force on the wood block (see Figure 11). Measure the total length of the wood block and the rubber band chain. Record the total length as the Start for the rubber band chain to the nearest centimeter in the data table.
   {12142_Procedure_Figure_11}
7. Insert a pencil through the leading rubber band loop. Position the tip of the pencil so it points to the centimeter-mark on the meter stick that was recorded as the Start for the rubber band chain (see Figure 12).
   {12142_Procedure_Figure_12}
8. Begin to stretch the rubber band chain by moving the pencil 1 cm to the right. Pause and observe whether or not the wood block moves.
9. If the block does not move, repeat step 8, moving the pencil and stretching the rubber band chain an additional 1 cm. Make sure the pencil is moved 1 cm at a time and always pause 2–3 seconds before moving the pencil again. Note: It is important to pause after each time the pencil is moved 1 cm since the block may slip just after the rubber band chain is stretched.
10. When the block moves for the first time, note and record the current position of the pencil in row 2 (block slippage 1) in the data table. Note: This should always be a whole centimeter. Also record to the nearest 0.1 cm where the leading edge of the wood block came to rest after it slipped.
11. Repeat steps 8–10 until the pencil point has reached the 100-cm mark or until the block has slipped 20 times, whichever comes first. Record the new positions of the pencil and the block in the appropriate row each time the block slips.

Activity C. Seismic Waves

Compression Wave

1. Obtain a piece of string and a Slinky spring.
2. Choose a coil of the spring about half way from each end and tie the string in a small bow around the coil (see Figure 13).
   {12142_Procedure_Figure_13}
3. Place the Slinky on the floor.
4. While a lab partner holds one end of the Slinky securely, grasp the other end and stretch the spring 2 m across the floor. Note: Take care to hold the ends of the Slinky securely. Do not allow the stretched Slinky to release suddenly.
5. With a free hand, carefully gather up a set of coils approximately 20 cm from the end and compress them tightly (see Figure 14).
   {12142_Procedure_Figure_14}
6. Making sure you and your partner are holding the opposite ends of the Slinky securely, without letting go of the end coil, release the compressed coils. Observe the compression wave as it travels the length of the Slinky, and note especially the motion of the string. Record observations in the data table.
7. Repeat steps 5–6 to complete your observations, noting how long the wave lasts.
8. Repeat steps 5–7, this time gathering up twice as many coils, about 40 cm from the end of the stretched spring. Note any differences in the movement and duration of the wave from the first two trials. Record observations.

Transverse Wave

1. Set up the Slinky as in steps 1–4 for the compression wave procedure.
2. With a rapid motion, shake the end of the Slinky sideways about 10 cm and back to its original position (see Figure 15).
   {12142_Procedure_Figure_15_Overhead view}
3. Observe the transverse wave as it travels the length of the Slinky, noting especially the motion of the string. Record all observations in the data table.
4. Repeat step 3 to complete your observations.
5. Repeat step 3 again, only this time moving the end of the Slinky sideways about 30 cm. Note any difference in the movement and duration of the wave compared to the first two trials.
6. Repeat step 5 to complete your observations.

Activity D. Resonance

1. Place the foam base of the resonance apparatus on a flat surface.
2. Slowly slide the base forward and back as shown in Figure 16. Start with a low frequency and gradually increase the frequency until one of the wires begins to resonate. Keep this frequency constant and observe the motion of the other two wires.
   {12142_Procedure_Figure_16}
3. Gradually increase the frequency of the back-and-forth motion of the base until a different wire begins to resonate. Keep this frequency constant and observe the motion of the other two wires.
4. Once again, gradually increase the frequency of the back-and-forth motion of the base until the third wire begins to resonate. Note: This will be a very vigorous back-and-forth motion. Keep this frequency constant and observe the motion of the other two wires.
5. Stop the motion of the base and record all observations in the data table. Repeat steps 2 to 4 as needed to confirm observations.

Student Worksheet PDF

12142_Student1.pdf