Information and Energy Transformations Demo

(The Laser-guided flame pipe)

Energy and information can be sent along any type of wave

Waves transmit energy! The unique characteristic of waves is that they can transmit energy, without the transfer of matter. By varying the frequency and amplitude vibration in a series of waves (called a wave train), we can send information with the wave. The first widespread use of this was the telegraph and Morse code. Sending this information along waves can be done at very low energy levels, and very low cost. Additionally, waves travel very fast compared to the alternatives (hand delivery, mail, or carrier pigeon).

What this demonstration shows

In this particular demonstration, information off a CD or vinyl record is transformed back and forth into different types of waves, but in each case, the information, that is, the amplitude and frequency variations of the original recording remain the same. This is true regardless of the type of wave or the medium that the wave travels through.

No matter what transformations take place, the original frequency and amplitude variation are preserved, so the information stream is also preserved, and the musical recording is still there.

Wave energy and signal transformations involved in the demo

Step / How the information is stored / Wave Transformation Involved
I / A record has vibrations in the grooves / Mechanical vibration  Electricity
II / An electrical signal sent to a laser to control how it flashes on & off / Electricity  Light
III / Laser light is reflected off a mirror / Light  Light
IV / The light beam hits a photocell / Light  Electricity
V / Electricity is sent through a coil / Electricity  Magnetism
VI / A nearby coil picks up the signal / Magnetism  Electricity
VII / The music is played by a speaker / Electricity  Sound
VIII / Flames dance with the music / Sound  Flame height

Detailed description of each step of the process

STEP IA Record player converts the original signal to electricity

As a record spins on a turntable a needle vibrates according to the pattern (wave train) imprinted on the vinyl. A transducer converts these vibrations into electricity – electrons moving back and forth at the same frequencies as the music, with the number of electrons determined by how loud each frequency is. (Information in equals information out)

OR

An audio CD is played in a CD player which produces an electrical signal (wave train) that is usually sent to a speaker. (A laser beam shines onto the CD, the light is reflected off the CD to create an electrical signal with the same frequency and amplitude variations as are stored on the CD.) (Information in equals information out)

STEP IIA Laser (light amplification by the stimulated emission of radiation) flashes on/off

This electrical signal is sent to a modulated laser where light (photons of energy) is produced. The light beam flashes on and off with the same frequency as the incoming wave train (signal). The number of photons produced (light intensity) corresponds to the amplitude of the incoming signal. (Information in equals information out)

STEP IIIA mirror can send the signal to where you want it to go

Light is reflected off a mirror across the room, similar to how satellites are used to transmit information around the world. Since light travels in a straight line, a mirror or satellite must be used to get the signal around obstacles (such as the earth) The reflected wave train is the same as the incoming wave train. This illustrates the principle of reflection.

(Information in equals information out)

Step IV A photocell converts light back into electricity

A photocell is placed in the path of the reflected light beam. According to the photoelectric effect, (for which Einstein won his Nobel Prize) when a photon strikes the surface of a metal atom (Silicon in this case), an electron is released. The number of electrons and the frequency of electrons being emitted are determined by the intensity and frequency of light that reaches the surface.

(Information in equals information out)

Step V A coil of wire converts electricity into magnetism

This photocell sends these electrons through a closed loop of wire. The electrons in the wire are sent around a circle many times, which converts this electrical signal into a magnetic field whose intensity and direction varies according to the intensity and direction of the electrons. This illustrates the relationship between electricity and magnetism.

(Information in equals information out).

Step VI Another similar coil converts the magnetism back into electricity

This coil is place near another similar coil. Just as electricity can create a magnetic field, a magnetic field can create an electric field. The electrons in this second coil move back and forth with the same frequency and intensity as the magnetic field that created it. If the coils are separated the signal gets weaker and can die.

(Information in equals information out)

Step VIIThe ends of the coil are connected to a loud speaker

The wires from this second coil are connected to an amplified speaker. (A speaker involves passing a coiled wire near a magnet. This makes the paper diaphragm on the speaker vibrate with the same frequency and amplitude as the electrical signal. What we recognize as sound waves are now produced for the first time.

(Information in equals information out)

Step VIIIA flame pipe dances with the music

The speaker is attached to the open end of a “flame pipe”, a 2 meter long iron tube connected to a gas supply (propane, butane or natural gas). Through 200 holes, spaced 1cm apart flames come out. The gas inside the pipe vibrates according to the frequency and amplitude of the vibrating speaker.

The height of the flames coming out varies according to the pressure variation of the gas inside, and hence dance with the music. Where the pressure inside is higher the flame height is greater. The wave pattern seen represents ½ of the wavelength of the sound waves. This tells us that the wavelength of a sound wave is on the order of several feet long.

With a spacing of 1cm, the very high fidelity signal becomes a low fidelity signal, so only the dominant tones are seen.

Conclusion:Information in equals information out

The original wave train contained in the grooves of a record is transformed from one type of wave to another. When waves are created, they have specific frequencies and amplitudes of vibration. A wave train can be reflected back and forth or transformed as many times as needed depending on how you want it to travel from one place to another. It doesn’t matter because the signal, stored as frequency and amplitude variations are preserved in each type of wave.

The speed at which electricity and light moves is fantastic and allows for almost instant communication anywhere in the world.