Types of Waves
Directions: Scroll down and double click on the web address under the title of each part of the activity and follow the directions to complete the activity.
Part 1: Transverse Waves I
Directions: Open the applet Transverse Waves I by double clicking on the web address above. Read the text below the simulation. Use the scroll bar to center the diagram and still have the tool bar on top and bottom of the screen to use. Follow instructions to answer the questions.
1. Click to place a dot in the circle beside progressive wave on the top. This means the wave only goes in one direction. (There is no interference) Click pulse. Describe what happens.
2. Click Continuous. What is the difference between a pulse wave and a continuous wave?
3. Click stop and draw a transverse wave. Label the following:
equilibrium line - where there is no displacement. d=0 the horizontal line in the center of the wave
a crest - the highest point, greatest positive displacement from normal
a trough - the lowest point, greatest negative displacement from normal
Amplitude - Distance from equilibrium to crest or trough.
4. Click string fixed at both ends. This is called a standing wave. A standing wave has nodes and antinodes.
Draw the standing wave and label the following:
node - point where no motion is occurring
antinode - point where the displacement from normal or equilibrium is greatest
5. Click- rod clamped at left end. Set Frequency to high, medium and low values. Draw and label node and antinode. Which end always has an antinode? ___________ (Fixed or Free end) Which end always has an node? ___________
6. Keep wavelength set on medium and change frequency (f ) from high to medium and then low. Describe what happens to the wave motion in each.
High f: __________________________________________________________________________
Medium f: __________________________________________________________________________
Low f: __________________________________________________________________________
7. Keep the wavelength and the frequency set on medium. Change the amplitude from low to medium to high. Describe how the wave changes.
8. Click on the stop button then click on the step button several times. Describe the motion of the particle (blue circle) with each step change.
9. What direction is the wave itself moving? _____________________________________
Part 2: Transverse Waves II
Directions: Open the website listed above. Go to View on the top tool bar and go to full screen. (the tool bar returns when you click on the restore button on the upper right hand corner) Read the text below the simulations and follow instructions to answer the questions..
1. Click pulse, equal amplitude, in phase, and slow on the bottom tool bar.
What is the red wave?______________________________________________________________
What is the blue wave?_____________________________________________________________
What is the yellow wave?____________________________________________________________
2. Click on stop and click step [stepÞ ] and/or [Ü step] enough times to observe what happens when the pulse waves overlap. How high, compared to the red and blue wave, is the yellow wave when the blue wave is exactly on top of the red wave? This is superposition or wave interference.
3. Click continuous, and click start. Is there a point or points on any of the waves where there is no motion?
4. Click stop, then step until the blue is on top of red (crest on top of crest and trough on top of trough). What happens to the yellow wave? This is a standing wave that results from constructive interference.
5. Draw and label nodes and antinodes of the standing wave produced. (see Part 1 if you forgot what they are)
6. Click stop then step until the red and blue exactly cancel. (Crest of blue over trough of red). This is total destructive interference. Describe the resultant wave (the wave produced).
7. Click on unequal amplitude. Is there any point on the wave that doesnt move?_____________________
If so label on drawing #5.
8. Stop and step several times. Is there any way to move the waves to get the big yellow wave with nodes and antinodes?
9. What must be true about the amplitude to get a standing wave?________________________________
10. Click equal amplitude and out of phase. Where are the red crests and troughs in relation to the blue crests and troughs?
11. What must be true to get standing waves?_______________________________________________
Part 3: Longitudinal Waves I
Directions: Open the website listed above.
Read the text below the simulations and follow instructions to answer the questions..
1. Draw the wave and label the following.
compressions- areas where the circles are the closest . The compressions are analogous to the crest on a transverse wave.
rarefactions- Where the circles are spread apart the most and are comparable to the troughs.
2. Change the wavelength and describe what happens.______________________________
3. Click continuous and step. Which direction are the circles moving compared to the direction the wave is moving. (Confirm or Establish answer at this site, if necessary: http://www.geocities.com/CapeCanaveral/Hall/6645/lontra_e/lontra_g.htm )
Note: In this simulation the particles appear to be moving from the left to the right side with the wave in an actual longitudinal wave they only move back and forth. They return to their original position after the wave passes.
Part 4: Longitudinal Waves II
Directions: Open the website listed above.
Read the text and follow instructions to answer the questions.
1. Draw this model of a longitudinal wave and label compressions and rarefactions.
2. Click continuous. Are nodes and antinodes formed when the red and blue wave interfere to form the yellow wave? Is it possible to form a longitudinal standing wave? ______________
Conclusion: Use the answers to the questions above to summarize what youve learned.
1. Define the following characteristics of waves:
trough / rarefaction-__________________________________________________________________
2. Compare the motion of the particles and the wave motion of a transverse wave and a longitudinal wave.
3. What is the difference between a pulse wave and a continuous wave?
4. What is a standing wave and how are they created?___________________________________________
5. What happens at the nodes and antinodes of standing waves?__________________________________
6. What characteristic(s) of waves must be equal to create a standing wave?_______________________