For middle school and up, a short explanation of the difference between transverse and longitudinal waves, with some suggestions for classroom presentation.
Waves are disturbances; they are changes in something - the surface of the ocean, the air, electromagnetic fields. Normally, these changes are travelling (except for
Standing Waves ); the disturbance is moving away from whatever created it.
Most kinds of waves are
transverse waves. In a transverse wave, as the wave is moving in one direction, it is creating a disturbance in a different direction. The most familiar example of this is waves on the surface of water. As the wave travels in one direction - say south - it is creating an up-and-down (not north-and-south) motion on the water's surface. This kind of wave is very easy to draw; a line going from left-to-right has up-and-down wiggles. So most diagrams of waves - even of sound waves - are pictures of transverse waves.
But sound waves are not transverse. Sound waves are
longitudinal waves . If sound waves are moving south, the disturbance that they are creating is making the air molecules vibrate north-and-south (not east-and-west, or up-and-down. This is very difficult to show clearly in a diagram, so most diagrams, even diagrams of sound waves, show transverse waves.
It's particularly hard to show
amplitude in longitudinal waves. Sound waves definitely have amplitude; the louder the sound, the greater the tendency of the air molecules to be in the "high" points of the waves, rather than in between the waves. But it's easier show exactly how intense or dense a particular wave is using transverse waves.
Longitudinal waves may also be a little difficult to imagine, because there aren't any examples that we can see in everyday life. A mathematical description might be that in longitudinal waves, the waves (the disturbances) are along the same axis as the direction of motion of the wave; transverse waves are at right angles to the direction of motion of the wave. If this doesn't help, try imagining yourself as one of the particles that the wave is disturbing (a water drop on the surface of the ocean, or an air molecule). As it comes from behind you, a transverse waves lifts you up and then drops you down; a longitudinal wave coming from behind pushes you forward and then pulls you back. You can view animations of longitudinal and transverse waves
here ,
single particles being disturbed by a transverse wave or by a longitudinal wave , and
particles being disturbed by transverse and longitudinal waves .
Transverse and longitudinal waves
In water waves and other
transverse waves , the ups and downs are in a different direction from their forward movement. The highs and lows of sound waves and other
longitudinal waves are arranged in the "forward" direction.
Presenting these concepts in a classroom
Watching movies or animations of different types of waves can help younger students understand the difference between transverse and longitudinal waves. The handouts and worksheets at
Talking about Sound and Music include transverse and longitudinal waves. Here are some classroom demonstrations you can also use.
Waves in students
Procedure
You will not need any materials or preparation for this demonstration, except that you will need some room.
Have most of the students stand in a row at one side of the classroom, facing out into the classroom. Let some of the students stand across the room from the line so that they can see the "waves".
Starting at one end of the line, have the students do a traditional stadium "wave". If they don't know how, have them all start slightly bent forward with hands on knees. Explain that the student on the end will lift both arms all the way over their heads and then put both down again. Each student should do the same motion as soon as (but not before) they feel the student beside them do it.
If they do it well, the students watching should see a definite transverse wave travelling down the line of students.
Starting with the same end student, next have the line make a longitudinal wave. Have the students start with their arms out straight in front of them. As the wave goes by, each student will swing both arms first toward, and then away, from the next student in line.
Let the students take turns being the first in line, being in line, and watching the line from the other side of the room. Let them experiment with different motions: hopping in place, swaying to the left and right, taking a little step down the line and back, doing a kneebend, etc. Which kind of wave does each motion create?
Jumpropes and slinkies
Materials and preparation
Rope - A jump-rope is ideal, or any rope of similar weight and suppleness
Coil - A Slinky toy works, or any metal or plastic coil with enough length and elasticity to support a visible longitudinal wave
Pole - A broomstick is fine, or a dowel, rod, pipe, or any long, thin, rigid, smooth cylinder.
You may want to practice with these items before the demonstration, to make certain that you can produce visible traveling waves.
Procedure
Load the slinky onto the broomstick and stretch it out a bit. Have two people holding the broomstick horizontally at waist level, as steadily as possible, or secure the ends of the broomstick on desks or chairs.
Holding one end of the slinky still, have someone jerk the other end of the slinky forward and back along the broomstick as quickly as possible. This should create a longitudinal wave that travels down the slinky to the other end. (If the other end is being held very tightly, but without interfering with its coils, you may even be able to see the wave reflect and travel back up the slinky.)
Secure or have someone hold one end of the jumprope very still at waist height. Stretch the jumprope out taut, horizontally.
Have the person at the other end of the jumprope suddenly jerk the end of the rope up and down again. You should see a transverse wave travel to the other end of the rope. If the other end is secured very tightly, you may even be able to see a reflection of the wave travel back to the other end.
With both of these setups, you can experiment with sending single pulses, multiple waves, or even try to set up
standing waves . In fact, a jumprope is usually used to make a sort of three-dimensional standing wave of the
fundamental of the rope length. Try making the standing wave in two dimensions, going just up-and-down (without the forward and back part of the motion). With a good rope and some practice, you may be able to get a second
harmonic standing wave, with one side of the rope going up while the other side goes down, and a node in the middle of the rope.
Questions & Answers
Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you.
Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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