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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

Wave Motion Help me with science Canada

Wave Motion What is a phase in wave motion? nepal

Waves Sloshing waves USA

Waves Surface waves USA

Wave Motion Ball game wave not a true wave Canada

Waves Light as wave and particle USA

Waves Electromagnetic waves travel in vaccuum USA

Wave Motion Wants to use a strobe light to stop motion USA

Wave Motion How are waves formed? Philippines

Waves and Obstacles Bell and the photophone USA

Next 10

First 10 letters

## Help me with science

Topic: Wave Motion

### Question

May 25, 2005

buh bye!

7081

Going through our lessons should give you some help. If you have a specific question, we'll try to answer it.

Don't give up. Make it your goal to understand the material and you should do better.

## What is a phase in wave motion?

Topic: Wave Motion

### Question

April 26, 2005

I have a Question for you and that goes like this. What is a phase in wave motion

nabin - nepal

6780

The phase of a wave is the position from a given point, like a peak. Since waves are sine waves, often the phase difference between two waves is given as an angle. Like: wave A is 20 degrees out of phase with wave B.

## Sloshing waves

Topic: Waves

### Question

March 11, 2001

I am a student at Boston University and I have to explain the physics of the sloshing back and forth of a cup of liquid as one walks. I have tried to find information on this subject for my project but have been having trouble finding this specific subject.

I know that the sloshing increases as you walk so I think this means that the frequency increases. Is this because the velocity increases? If you have any useful information on this subject or have any suggestions on where to look, I'd greatly appreciate it. Thank you very much.

- USA

6672

When people walk, the movement is jerky and uneven. It is not as if we had wheels. The distance of the movements are actually greater than the wavelength in the material and slower than the natural frequency. It is like holding a cup of water when sitting in a row boat. The water in the cup will imitate the waves moving the boat and they are much longer than the width of the cup.

In addition to a cup of water, you might show what would happen if you were carrying a plate of Jell-O. It would also jiggle more as you walked. Likewise, if you carried a weight on a string, which would swing more.

## Surface waves

Topic: Waves

### Question

October 12, 2001

We are having no luck finding a definition of "Surface Waves" for my son's final exam in 8th grade science. They have been studying sound, so I assume they must mean acoustic surface waves. We would appreciate your help.

- USA

6671

Surface Waves are waves that have a combination of transverse and longitudinal motions. The most common example are waves on the surface of water. Another example are waves created when an earthquake occurs.

## Ball game wave not a true wave

Topic: Wave Motion

### Question

April 4, 2005

you mentioned wave in a ball game as an example for how an actual wave behaves. this is not correct, however, since although that after standing up and down every one is still in their seats, no energy is being transmitted from one individual to another (each person uses his or her energy to make the "wave"). In an acutal wave, energy is tranmitted from one partical to another.

6535

That is a good observation. It is correct that the "wave" in a ball game is not a real wave in the strict sense, since each person is acting on their own and no energy is transmitted. But it does have the same features as a real wave: wavelength, velocity, and amplitude.

## Light as wave and particle

Topic: Waves

### Question

March 11, 2005

In you chaper about waves you said that light is a wave please inform me in wther i am incorrect in saying light is made of photons not waves.

Eric - USA

6301

Light has a dual nature of being both a wave and a particle. It is a basis of Quantum Mechanics that particles can have wave properties.

## Electromagnetic waves travel in vaccuum

Topic: Waves

### Question

March 4, 2005

On your site says: "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"

But if light and all electromagnetic waves can travel in vaccuum, what medium is being disturbed?

Luis - USA

6212

A vacuum is space where there is no matter. But in a vacuum, there are still force fields such as gravity, electrical and magnetic fields. Distortions in the electrical and magnetic fields are what result in electromagnetic waves.

There is no god exaplantion of what those fields consist of.

## Wants to use a strobe light to stop motion

Topic: Wave Motion

### Question

February 11, 2005

I am working on my 6th grade science fair project. I want to show the vibration of a Harp string with a stobe light ( i play the harp)to show and compare a wave from a earthquake. I ordered a small strobe with and adjustment of 1-12 flashes per sec. I cant seem to get the effect I am looking for. Could you help me .Does the strobe light need to flash more/sec? Thanks

ER.

- USA

5940

The harp string is vibrating too fast for your strobe light. You might try something else.

If you have a small battery-powered electric motor from some toy and have it rotate a disk or wheel with a mark on it, you should be able to adjust the strobe light to mark the mark appear to stand still. Then attach a length of string to a point on the edge of the wheel and have the other end tied down a distance away. You should get a regular wave motion similar to the harp string, but much slower. Your strobe should then be able to freeze the motion of the string.

I hope that helps. Let me know how your project turns out.

## How are waves formed?

Topic: Wave Motion

### Question

January 30, 2005

can you show me how the different kinds of waves are formed?
im a student who is making a research on how waves are formed. thank you.

sheryll - Philippines

5784

Sound waves are made by the back-and-forth motion of some object like a loudspeaker, guitar string or vocal cords. Water waves are made by regular motion in water from wind or vibrations. Light waves are made by regular motion of electrons.

## Bell and the photophone

Topic: Waves and Obstacles

### Question

January 26, 2005

Light as a transmitter of sound:I have been reading about alexander graham Bell,inventor of telephone..he has a patented devise know as the PHOTO PHONE as it is credited with sending sound thru light waves.I have been unable to find out anything.Is this something unusefull or hidden?

Stephen - USA

5740

The photophone was just before its time. It was impractical for long distance transmission until the inventioon of fiber optics.

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