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# Feedback Comments on Wave Motion

by Ron Kurtus

A total of 91 comments and questions have been sent in. They are listed according to date.

## List of next 10 letters

### Country

Waves What exactly is a wave? INDIA

Wave Motion Waves on an oscilloscope Pakistan

Waveform Noise People at work play the radios too much USA

Wave Motion Does a wave travel faster in air or water? USA

Waveform Noise Can you point a sound at the source to cancel it out? USA

Wave Motion Why does a water wave look like it is moving? India

Wave Motion Doesn't a tsunami move much water many miles? England

Waves Can electrons be waves? INDIA

Waves How do sound waves propagate at different water le INDIA

Wave Motion How to calculate the wave velocity using a Slinky? India

Next 10

First 10 letters

## What exactly is a wave?

Topic: Waves

### Question

April 20, 2006

hai ,
i'm a college student .we as student I believe are not fed with right basics.
I read ur definition for wave motion but i just cant understand what excatly is a WAVE . does WAVE signify or mean ENERGY or is it just another kind of motion. what is the difference between WAVE and a PARTICLE(atom)

IBRAHIM - INDIA

10891

A wave is a periodic vibration in a material. A good example is a water wave. You can't see sound waves, but you can see how a loudspeaker creates vibrations in the air. The vibration or movement of the material means that energy is created from the movement. It take energy to move matter.

But with light waves, the movement is in the electrical and magnetic fields. This is more difficult to understand. Still, the movement results in energy, as can be seen in light heating up an object.

Quantum Theory states that atomic and sub-atomic particles can somehow behave as if they were waves. It also says that light waves sometimes behave as if it consisted of particles, called photons.

## Waves on an oscilloscope

Topic: Wave Motion

### Question

March 27, 2006

My question is that Is this possible that at same time wave exist and frequency is not?

Second question is that On oscilloscope checking wave motion of Alternating Current, it shows sine wave which is actually transverse wave and in the topic compression waves you explained that Alternating Current is Compressed wave, am i right?

Last and third question is that can we say that light motion is somewhat spiral type

10639

You can draw a sine wave. Since it does not move, it has no frequency.

Alternating current in a wire as well as sound waves are both compression waveforms. The problem is that it is difficult to illustrate compression waves, so they are usually shown as transverse wave, such as a sine wave on an oscilloscope. That makes it easier to study.

Partially polarized light can have a spiral motion. You can see a demonstration at:
http://www.school-for-champions.com/science/experiments/simwaveform.htm

Note that it is a Java application that takes a while to load.

## People at work play the radios too much

Topic: Waveform Noise

### Question

February 12, 2006

I have a problem at work - people surround me with radios and it's driving me insane. It's giving me such bad headaches due to stress I guess , to the point I want to cry. I asked management to move me or require the people to wear earphones - no to both but they said they will require them to turn the radios down. I still hear them only now it sounds like a million squeaking rats running around. They had me get a hearing test and it resulted in left ear is 10 db and the right ear is 14 db. The doctor said I have Hyperacosis which I believe he said I have sensitive ears. I also have Tinnitus (ringing) in the left ear. How can I make these bosses understand that I'm hurting mentally and physically from this. I don't want to get fired but what avenue is open to me to file a complaint to prove I hurt. I can find articles that state even low levels of noise can constiute health and safety hazards because it increases stress but I think I need a legal organization that they would listen to and that would back me up. Is their any advice you can offer me? I am almost 62 and they just may be trying to get me to quit. I can't afford to - I've been there 10 years and have an unblemished work record. Only my age is against me now. Help please!

Shirley - USA

10051

Apparently, there are enough people who want to listen to their radios at work that management feels it is better to keep them happy than give it to your complaints, even though it is stressful for you. It is a case of majority rules. You could complain to the government OSHA offices, but it probably wouldn't do much good and you could lose your job.

Putting in earplugs may help to protect you from the noise somewhat, but a better solution is to get some noise reduction earphones. Instead of listening to their music, you can block out most sounds. They also allow you to listen to your radio or music if you wish. For an explanation of them, see:
http://www.school-for-champions.com/science/noise_cancellation.htm

Bose has such headsets for \$200, Sony for \$100 and there are some for around \$30. It might by a way for you to work in peace without having to listen to all those other sounds.

By the way, many people over 50 get tinnitus. It is annoying but people learn to live with it.

Best wishes in solving you problem at work.

## Does a wave travel faster in air or water?

Topic: Wave Motion

### Question

February 9, 2006

Does a wave travel faster in air or water?

Herbert - USA

10014

A sound wave travels faster in water. A light wave travels faster in air.

## Can you point a sound at the source to cancel it out?

Topic: Waveform Noise

### Question

February 6, 2006

Is there anything avalible that will cancel out sound if pointed in the direction of that sound. In other words is there a device that can cancel out a near by sound like radio, machines, and people so you wont here anything?

- USA

9968

The problem is that you need to know the exact waveform to cancel out a signal. If the noise source was a very regular noise, like from a motor, a wave might be able to be pointed at it to cancel it out. But in the real world, there isn't anything like that.

## Why does a water wave look like it is moving?

Topic: Wave Motion

### Question

January 30, 2006

When a wave is formed in water it is said that the particles are just moving in theirown position, but why then if any disterbence occurs in sea the water is rushing into the land?

yours faithfuly

jithu - India

9860

The water particles move in a circle in a water wave that is about the height of the wave. The motion of one circle causes the next group of water particles to move in a circle and so on. When the water gets shallow toward the land, the circle gets larger and larger, causing it to seem like the water is rushing to the land. If you notice, the water wave moves in and then moves out at the shore, completing its circle.

## Doesn't a tsunami move much water many miles?

Topic: Wave Motion

### Question

November 26, 2005

You say that a wave is a distortion in a material or medium, where the individual parts of the material only cycle back-and-forth or up-and-down, but the wave itself moves through the material.

Surely a giant tsunami actually moves a huge bulk of water many thousands of miles

It seems then that your original statement is not correct???

I look forward to your explanation....thank you

Peter Webb

Peter - England

9111

The water in ocean waves travels in a circle, which is about the size of the wavelength of the wave. So the water molecules stay pretty much in one area, but the energy is transmitted to neighboring molecules. When the water becomes shallow, close to shore, the circle is disrupted and causes the wave to get higher and then to break.

Now with a tsunami, the wavelelgth is very long, often several kilometers. That means the bulk of water is traveling within that distance, but it transfers a large amount of energy and travels very rapidly. When it reaches shore, the wave will continue to travel up the shore, according to its wavelength.

## Can electrons be waves?

Topic: Waves

### Question

August 27, 2005

1) de Broglie in 1923 suggested that the motion of electrons might have a wave aspect.what this actually means? are electrons moving like a wave or the movement of electrons produces waves? i am asking about the quantum aspects.

2)quantization does occur inwave motion.what is the meaning of this sentence?can you explain it?

sajith - INDIA

7907

Although we normally think of electrons as tiny balls, one newer theory is that they exist as a cloud and another that they are tiny strings. In either case, electrons can have a wave associated with them, when they are moving.

This brought about the concept of the duality of matter, in that all sub-atomic particles can be both a particle and a wave. Also, as part of this, electromagnetic waves or light is not only a wave, but is also a particle called the photon. This can be called the quantization of a wave, where it is also a particle.

## How do sound waves propagate at different water le

Topic: Waves

### Question

August 5, 2005

Hello sir I am working in research institute. My doubt is if i drop rod of 50 kg weight in a water filled vessel how the sound waves propogate in water at different level?. I also want to pick up the impact signal thro a wave guide which is inserted into the water

Thank you sir

M.ANANDARAJ - INDIA

7726

Water pressure at different depths will affect the elasticity and density of the water. The relationship is: v = SQRT(E/d), where v is the velocity, E is the elasticity and d is the density.

But another factor comes into play with the depth of the water, and that is the temperature. The velocity is proportional to the square root of the temperature.

Since you are using a water-filled vessel, these factors may be trivial.

## How to calculate the wave velocity using a Slinky?

Topic: Wave Motion

### Question

August 5, 2005

How to calculate the wave velocity using a slinky?
How do you measure wavelength and time taken for wave propagation?

Sabitha - India

7725

Stretch the Slinky to a given length. Measure that distance. Start a wave with the Slinky. Use a stopwatch or other timing device to measure the time it takes for the wave to reach the end. The speed or velocity is then the distance divided by the time.

If you make several waves, you can measure them with a ruler.

Another way is to measure the time between the first reaching the end and the second. Since you know the velocity, you can divide it by this time to give the wavelength.

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