In this lab, you will study the transverse standing waves formed along a vibrating taut string attached to a rotating electric motor. At certain speeds, the motor will create transverse standing wave patterns along the string length between the motor and the pulley.
The string is held taut by the motor on one end and the mass dangling below the pulley at the other end. These transverse standing waves will only appear under certain conditions, which is what you will investigate in this lab.
In this lab, a standing wave pattern is produced by an electric motor that vibrates one end of the string up and down. As this happens, the string displacement is sent from one end of the string to the other. At this other end, which is fixed, the incoming wave reflects and bounces back in the other direction. When it reaches the end with the motor, it is reflected back, and this repeats again and again. However, if the reflected wave traveling to the left is in phase with the original wave traveling to the left, then their amplitudes constructively interfere.
Similarly, the leftward moving wave and a rightward moving wave may interfere destructively. The combination of all of these interactions yields a standing wave pattern, as shown in the diagram below, which looks like a stationary wave pattern, rather than many separate waves traveling to the left and to the right.
Depending on the speed of the electric motor, different frequencies can be generated along the length of the string, so long as there are nodes at the two fixed endpoints. In this lab, you will generate many standing wave modes like these, while exploring the relationship between the string's properties and those of the standing wave pattern produced.
As you might have guessed, the physics to be discussed in this lab applies very well to stringed musical instruments like the guitar, violin, and cello.
When playing one of these instruments, a musician is controlling the frequency of sound produced by the standing waves formed along the strings, generated by their fingers, a pick, or a bow. However, when the string is lightly pressed down along the neck of the instrument, the effective string length shortens, and the string no longer vibrates in its lowest order mode.
If you're familiar with stringed musical instruments, you should be able to anticipate the outcome of the investigations you'll conduct in the lab today! You can then compare your experimental value to your predicted value of wave velocity. An example with 11 nodes not counting the end points and 12 anti-nodes is shown in the picture below. Higher voltages produce higher frequencies, since more energy is sent into the string. First, position the photogate so that its beam is blocked by the small metal flag on the motor when it is vertical, which will happen once per cycle.
For plotting, you should use the web-based Plotting Tool. Regardless of your findings, what potential sources of error may have influenced your results? Because the elastic golden string would change its length for different amounts of mass attached, and thus its linear mass density would vary, you must first replace the golden string with the white non-stretchy string. Does your estimate equal this value within experimental uncertainty? User Tools Register Login.
Site Tools. The purpose of this lab is to study transverse standing waves on a vibrating string.Most curricular materials in TeachEngineering are hierarchically organized; i.
Some activities or lessons, however, were developed to stand alone, and hence, they might not conform to this strict hierarchy. Related Curriculum shows how the document you are currently viewing fits into this hierarchy of curricular materials.
Earthquake engineering focuses on protecting people and the natural and human-made environments from earthquakes by limiting seismic risk. This involves applying an understanding of seismic waves in order to create and maintain structures and urban infrastructure to perform to expectations when under duress from seismic loading due to seismic waves.
A properly engineered structure does not necessarily have to be extremely strong or expensive; it has to be properly designed to withstand the seismic forces while sustaining an acceptable level of damage. Each TeachEngineering lesson or activity is correlated to one or more K science, technology, engineering or math STEM educational standards.
In the ASN, standards are hierarchically structured: first by source; e. View aligned curriculum.
Do you agree with this alignment? Thanks for your feedback! Students learn about how engineers design and build shake tables to test the ability of buildings to withstand the various types of seismic waves generated by earthquakes. Just like engineers, students design and build shake tables to test their own model buildings made of toothpicks and mini marshm They make a model of a seismograph—a measuring device that records an earthquake on a seismogram.Vibrations and Waves - Pendulums
Students also investigate which structural designs are most likely to survive an earthquake. This lesson introduces the concepts of wavelength and amplitude in transverse waves. In the associated activity, students use ropes and their bodies to investigate different wavelengths and amplitudes. Students learn about the types of waves and how they change direction, as well as basic wave properties such as wavelength, frequency, amplitude and speed. During the presentation of lecture information on wave characteristics and properties, students take notes using a handout.
Generally know about the Richter magnitude scale, which indicates the intensity of earthquakes on a 1 to 10 base logarithmic scale. In advance, prepare a computer projector to show students the attached slide PowerPoint presentation and short videos at the end of this introduction, and make copies of the accompanying note-taking worksheet.
Why do you think engineers might be concerned about earthquakes? Give students a minute to think and write down answers before asking them to share their thoughts. Can you think of any big earthquakes that you have heard of in your lifetime?
The earthquakes in Haiti and Chile happened within a month of each other; do you know which one resulted in the most damage and led to the greatest loss of human life? Students may not know, so give them more information Well, the earthquake in Chile rated an 8. This means the earthquake in Chile was about times stronger than the earthquake in Haiti. So which earthquake resulted in the most damage to human-made structures and thus, loss of lives?
Listen to student guesses. Well, reports say about deaths in Chile, and more thanfatalities in Haiti!
physics waves and sound question please
That means that the earthquake with the lower intensity caused the most damage. Why do you think this was the case?Teaching Info. Personal Info. Web Plans. Site Map. Waves are a wiggle in space cause by a vibration or disturbance. They have the ability to carry energy from one location to another.
There are two different types of waves; transverse and longitudinal. A transverse wave is when the wave is vibrating perpendicular to the direction the wave is traveling. A longitudinal wave, also called a compression wave, is a wave in which the vibration is in the same direction as that in which the wave is traveling. How frequently a wave or vibration occurs during a span of time, determines the waves frequency.
Frequency is the number of waves per unit time. The speed a wave travels is the wavelength multiplied by this frequency. The amplitude of a wave is the maximum distance the wave is displaced.
Waves are characterized by several distinct behaviors. One behavior is interference. Wave will combine with each other, causing an interference. There are two types of interference.
Constructive interference is when two or more waves combine, and the amplitude of their resultant wave increases.
Destructive interference is when two or more waves combine and the amplitude of their resultant wave decreases. Waves will also diffract. Diffraction is the bending of waves when they hit a barrier. Sound is the result of vibrations in molecules causing the molecules to compress and retract, making sound a longitudinal wave.
The vibrating source must push some material medium, e. Therefore sound cannot travel in a vacuum where there is not matter.Embed an image that will launch the simulation when clicked. This simulation lets you see sound waves. Adjust the frequency or volume and you can see and hear how the wave changes. Move the listener around and hear what she hears.
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Search the PhET Website. Download Embed close. PhET is supported by. Topics Sound Waves Description This simulation lets you see sound waves. Sample Learning Goals Explain how different sounds are modeled, described, and produced. Design ways to determine the speed, frequency, period and wavelength of a sound wave model. Version 2. For Teachers.
Teacher Tips Overview of sim controls, model simplifications, and insights into student thinking PDF. Related Simulations. Wave Interference Waves Intro. Software Requirements. Windows Macintosh Linux Microsoft Windows. Latest version of Java. Java by Matthias Pfisterer. Offline Access Help Center Contact. Source Code Licensing For Translators.A wave is a continuous and repeating disturbance of a medium and a pulse is a single disturbance. In longitudinal waves, particles of the medium vibrate to and from in a direction parallel to the direction of energy transport.
If energy is transmitted along a medium from the east end to the west end, then particles of the medium would vibrate eastward and westward. A sound wave is a longitudinal wave but not the answer since a wave which exhibits this characteristic is not necessarily a sound wave. In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport. A transverse wave is traveling through a medium. See diagram below. In this case, that would be parallel to the line AD.
If the particles only moved north and not back south, then the particles would be permanently displaced from their rest position; this is not wavelike. The speed of a wave or a pulse depends upon the properties of the medium. If the medium is uniform or unchanging, then the speed is constant. The speed of a wave is dependent upon the properties of the medium and not the properties of the wave. As a wave crosses a boundary into a new medium, its speed and wavelength change while its frequency remains the same.
If the speed increases, then the wavelength must increase as well in order to maintain the same frequency. As a wave passes across a boundary into a new medium, which characteristic of the wave would NOT change? The amplitude of a wave is measured from rest to crest or from rest to trough; but not from crest to trough.
Thus, take the 0. The wavelength of a wave is measured as the distance between any two corresponding points on adjacent waves, which would mean from a crest to the next adjacent crest.
Thus, the distance from point b to point d is the wavelength - 0. A wave X meters long passes through a medium with a speed of Y meters per second.
The frequency of the wave could be expressed as. From point A to point E is one full wave cycle. After point E, the wave begins to repeat itself, but only for one-half of a cycle. Thus, there are 1. This distance represents two-thirds of the 60 cm from A to G. This is a basic definition which you should know and be able to apply. A periodic and repeating disturbance in a lake creates waves which emanate outward from its source to produce circular wave patterns.
If the frequency of the source is 2. What is the frequency of a wave that has a speed of 0. Many wave properties are dependent upon other wave properties. Yet, one wave property is independent of all other wave properties. Which one of the following properties of a wave is independent of all the others? The speed of a wave is dependent upon the properties of the medium through which it moves, not upon the properties of the wave itself.
A pendulum makes exactly 40 vibrations in Be cautious of the units. The period is the time for one complete cycle.
If the pendulum takes 20 seconds for exactly 40 vibrational cycles, then it must take 0.Embed a running copy of this simulation. Use this HTML to embed a running copy of this simulation.
You can change the width and height of the embedded simulation by changing the "width" and "height" attributes in the HTML. Embed an image that will launch the simulation when clicked.
Explore the wonderful world of waves! Even observe a string vibrate in slow motion. Wiggle the end of the string and make waves, or adjust the frequency and amplitude of an oscillator. Browse legacy activities. Share an Activity! Translate this Sim. Macintosh Systems: macOS Linux Systems: Not officially supported.
Please contact phethelp colorado. Skip to Main Content. Sign In. Time to update! We are working to improve the usability of our website. To support this effort, please update your profile! Skip for now. Search the PhET Website. Download Embed close. PhET is supported by. Original Sim and Translations About.
Wave on a String
Sample Learning Goals Discuss wave properties using common vocabulary. Predict the behavior of waves through varying medium and at reflective endpoints. For Teachers. Teacher Tips Overview of sim controls, model simplifications, and insights into student thinking PDF. Please sign in to watch the video primer. Related Simulations. Software Requirements. Offline Access Help Center Contact. Source Code Licensing For Translators. Some rights reserved. Overview of sim controls, model simplifications, and insights into student thinking PDF.
Waves on a String Inquiry Based. Algebra-based Physics Semester one lessons, clicker questions, and schedule in pdf Inquiry Based.Get a free answer to a quick problem. Most questions answered within 4 hours. Choose an expert and meet online. No packages or subscriptions, pay only for the time you need. My question is at the bottom of the procedure.
I've solved for everything else. Here's the procedure for the lab:. Hold one end of a meter yard stick down on a tabletop so that 20 cm of the stick extends past the edge of the table. Pluck the end of the stick extending past the edge of the table to produce a vibration and sound.
Observe this vibration and sound and record your observations. Repeat the step above, but this time double to 40 cm the length of the stick that extends from the table. Repeat this step again, allowing the meter stick to extend 60 cm from the edge of the table. Take the cardboard tube and make a kazoo by cutting a hole in the middle of the tube. Make the hole approximately 1 cm in diameter. Use a rubber band to secure a piece of wax paper over one end of the cardboard tube.
Make another kazoo following the same instructions as above, but cut the cardboard tube 10 cm shorter than the first tube.
PHY 133 Lab 9 - Standing Waves
Hum into each of your kazoos created above. Try to make the humming noise as consistent as possible in each tube. Observe and record how the length of the kazoo affects the pitch of the sound produced. Cut the neck off the balloon. Replace the wax paper on the longer kazoo with the cut balloon, wrapping the rubber band around the end of the cardboard tube. The rubber band should hold the tightly stretched balloon over the end of the tube. Use tape to attach the small mirror to the balloon at the end of the tube.
Get a helper to shine a flashlight on the mirror while you hum into the kazoo. The helper should position the flashlight so a spot of light is reflected on the wall you may have to darken the room. Observe how the light moves as you hum into the kazoo. Note your position and the position and angle of both the kazoo and the flashlight.
Raise the pitch of your humming while keeping the loudness the same. Observe how the spot of light differs from the step above. Keep the distance from the wall and the angle at which the light from the flashlight strikes the kazoo the same. Repeat the above step while humming at a lower pitch. Repeat the above two steps, but this time vary the loudness while keeping the pitch constant. Add comment. That sounds like THE question the lab is supposed to lead you to?
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