Lab ActivityBuilding A Wave MachineConceptual Physics
Objective:
Build a wave machine that demonstrates various wave phenomena. Observe and record wave motion as wave characteristics are altered.
Materials:
Duct tape, scotch tape, bamboo skewers, pen, gumdrops/gummy bears/jelly babies, mounting frame
Procedure:
1. Measure the width of the duct tape. Divide the number by 2. Record measurement here:
2.Find the middle of the skewer, and mark (copy measurement from above) cm on either side of the skewer. This will help you center the skewers on the duct tape. (Two students will do this task. Group A)
3.Measure the distance between the support rods (in cm) and record here: cm.Measure out a piece of duct tape that is 60 cm longer than the distance between the support rods. Lay duct tape sticky side up. On both long edges of the tape, use a sharpie marker and mark every five centimeters down the duct tape. Place your first mark 30 cm from one end and leave 25 to 30 cm free on the other end. (Two students will do this task. Group B)
4.Spear a gum drop, gummy bear or jelly baby in either end of a skewer. Make one skewer for each spot marked on the duct tape.(Two students will be doing this task. Group A, and Group B when task #3 is complete.)
5.Tape the loaded skewers perpendicularly onto the duct tape, 5 cm apart.(All students should help with this task.) Be sure skewers are taped parallel to each other and centered on the tape.
6.Repeat procedures 4 & 5 until the duct tape is full.
7.Measure out a second strip of duct tape that is 20 cm longer than the distance between the support rods. Tape it on top of the skewers, sticky side down. Using the sticky ends of the duct tape, hang your wave machine onto the metal supports. All students in group can assist in this task by collectively supporting the duct tape.
8. Follow the Analysis Questions and record your observations in your lab book.
Lab ActivityBuilding A Wave MachineConceptual Physics
Objective:
Build a wave machine that demonstrates various wave phenomena. Observe and record wave motion as wave characteristics are altered.
Materials:
Duct tape, scotch tape, bamboo skewers, pen, gum drops/gummy bears/jelly babies, mounting frame
Procedure:
1. Measure the width of the duct tape. Divide the number by 2. Record measurement here:
2.Find the middle of the skewer, and mark (copy measurement from above) cm on either side of the skewer. This will help you center the skewers on the duct tape. (Two students will do this task. Group A)
3.Measure the distance between the support rods (in cm) and record here: cm.Measure out a piece of duct tape that is 60 cm longer than the distance between the support rods. Lay duct tape sticky side up. On both long edges of the tape, use a sharpie marker and mark every seven centimeters down the duct tape. Place your first mark 30 cm from one end and leave 25 to 30 cm free on the other end. (Two students will do this task. Group B)
4.Spear a gum drop, gummy bear or jelly baby in either end of a skewer. Make one skewer for each spot marked on the duct tape. (Two students will be doing this task. Group A, and Group B when task #3 is complete.)
5.Tape the loaded skewers perpendicularly onto the duct tape, 7 cm apart. (All students should help with this task.) Be sure skewers are taped parallel to each other and centered on the tape.
6.Repeat procedures 4 & 5 until the duct tape is full.
7.Measure out a second strip of duct tape that is 20 cm longer than the distance between the support rods. Tape it on top of the skewers, sticky side down. Using the sticky ends of the duct tape, hang your wave machine onto the metal supports. All students in group can assist in this task by collectively supporting the duct tape.
8. Follow the Analysis Questions and record your observations in your lab book.
Lab ActivityBuilding A Wave MachineConceptual Physics
Objective:
Build a wave machine that demonstrates various wave phenomena. Observe and record wave motion as wave characteristics are altered.
Materials:
Duct tape, scotch tape, bamboo skewers, gum drops/gummy bears/jelly babies, mounting frame, rulers, meter sticks and sharpie markers
Procedure:
1. Watch the video on making a wave machine. In your group, discuss how you will make a wave machine. Consider the following questions as your group plans and builds a wave machine. As you discuss the sequence and steps, write down answers to the following questions.
a. Does it matter what kind of candy is stuck to the end of the skewers? What kind did you choose?
b. Does it matter how the skewers are placed on the duct tape?
(crooked vs. straight/ duct tape in the middle of the skewer)
c. How will you make sure the skewers are placed straight and in the middle?
d. Does it matter if the skewers are evenly spaced?
e. How close should the skewers be to each other? How will you be sure they are evenly spaced?
f. How will the duct tape be anchored to the supports?
g. The wave machine will work best if it is reinforced. Will you put a second strip of duct tape on top of your skewers?
2. Build your wave machine! Each student should be involved. (tasks include: measuring the distance between the mounting frame, measuring and marking duct tape, measuring and marking skewers, putting jelly babies on the ends of the skewers, placing the skewers on the duct tape, reinforcing with another piece of duct tape, mounting the machine on the frame)
3. Make some waves! Test your machine, balancing and tightening the slack as needed.
4. Follow the guidelines on the other side of the paper. Make observations and answer the analysis questions.
Guidelines:
- Always stop all waves on the machine prior to making the next set of observations.
- A wave pulse is a single burst of energy.
- A periodic wave is generated from repeated motion at a regular time interval (period).
Observations and Analysis Questions:
1. Send a pulse down your wave machine by gently lifting a jelly baby up and pushing it down.
What moves through the machine, energy or the jelly babies? How do you see the energy moving?
2.Time how long it takes for the wave to move from one end of the machine to the other. Three students should be timing. Repeat for 3 trials. Find the average time. Measure the length of the machine (in m, to the nearest cm) and determine the velocity of the wave. (v = d/t)
3. Repeat stepsone and two with a different amplitude (lift the jelly baby higher or not as high). How is the wave different? Does amplitude affect the velocity of the wave? Time it to find out!
4. a. What kind of wave have you been making in your machine? Explain.
b. How could you move the jelly babies/skewers to make a compression wave?
(Be gentle! Don’t break your machine!)
4. What happens to the wave when it reaches the other end of the machine?
5. Generate a periodic wave on your wave machine. Alter the frequency of the periodic wave. Can you find a frequency that generates a repeating wave pattern? Describe the pattern. How many waves do you see?
6. What happens to your wave pattern if you increase the frequency of the wave? How many waves do you see now?
7. Make a statement about the relationship between how changing the frequency changes the wavelength of a wave.
Analysis Questions:
1. At one end of the wave machine, lift one jelly baby up and let go. Record your observations. From your observation, finish the following sentence: Waves transmit not .
2. Repeat step one with a different amplitude (lift the jelly baby higher or not as high). How is the wave different? Does the wave move down to the other end faster? (Time it!)
3. What happens if you start a periodic wave rather than a pulse?
4. What was the spacing on your wave machine? What kind of gummy did you use?
5. Find another wave machine with the same spacing, but different gummies on the end. Send a wave pulse down the machine. How is the wave different than yours?
6. Find another wave machine with a different spacing, but the same gummies as yours. How does the wave pulse on the other machine differ than yours?