Experiment 304:Kundt’s Tube: Velocity of sound in solid

Experiment No. 304: Kundt's Tube: Velocity of Sound in Solid

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This exp experiment we condu nduct was to determine the velocity of sound traveling in a medium. The metal rod was enclosed in a tube tube glas glasss with with some some powd powder er that that can can illustrate the velocity of sound that we are apply applyin ing g to the the rod rod by pulli pulling ng back back and and forth. This friction causes vibration and later  it would be converted to sound inside the tube. ube. This his expe experrimen imentt woul would d als also be determine the speed of the sound traveling throughou hout the tube by apply plying the  principles of resonance.

tube is a closed type apparatus because of  the one end stopped by a cork.

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!or the "st part as show in figure in figure – 2 above we need to check if the rod was clamped at the middle. #e also checked the cork that clos closed ed the the tube tube if it was was inta intact ct.. #e then then  place it at the side of the table for it to be easily used by the demonstrator.

In this experiment we will be using materi materials als as shown in  figure-1 are Kundt’s Tube Apparatus meter stick piece of cloth thermometer and rosin lycopodium powder. The Kundt’ Kundt’ss tube tube consist consistss of a hollowe hollowed d glass tube a metal rod and some clamps to secure the rod in position. The metal rod is needed to be clamped at the middle to saw good outcomes through the experiment. The

In figure – 3 our group mate demonstrate the  pulling back and forth of the rod with rosin  powder $ figure – 4)  inside the cloth. This vibration of the rod was due to the energy that comes from the friction produced by stroking cloth at the rod. The waves  produced inside after vibration is visibly seen through the change of the powder’s  pattern inside the glass tube.

In figure – 6 we were measuring the distance  between successive powders but it is difficult to be measured accurately because we can’t locate the exact center of the dust. #e average the lengths of all the distance and used that data. &*T* +nd S*$,E "O$,-T*T#ONS Kundts Tube : Velocity of Sound in Solid 91.2 cm

%ength of metal rod  Lr After the demonstration. #e examine the tube and gathered data to be used for the computation. #e also need to get the room temperature of the air as shown in figure –5.

Average

length

of  

10.5 cm

 powder segments  La Temperature of air

t 

&elocity of sound in air

27 °C  348.2 m / s

va

&elocity of sound in the rod

v r  $'(uation )*

Velocity of sound in t/e rod

3024.27 m / s

v r   1Textboo2

3475 m / s

 

+ 'rror 

,ensity of the rod 

12.971  p

 

&elocity of sound in the rod v r $'(uation -*  

+ 'rror 

vr =

3

8700 kg / m

3234.157 m / s

√

 9.1 × 1010

10

 N / m

8700 kg / m

2

3

v r =3234.157 m / s

6.931

,ercent Error:

Velocity of sound in t/e rod

vr

1Eu+tion 3:  Lr × v a vr =  La vr =

error =

error =

91.2 cm× 348.2 m / s

α actual −α exp α actual

3475 −3234.157 × 100 3475

error =¿

10.5 cm

× 100

.735 9

v r =3024.27 m / s (;*,%

 Temperature vs. Velocity of sound

,ercent Error:

3060

error =

α actual −α exp α actual

3040

× 100

Velocity of sound (m"s! 3020 3000

error =

2980 24

3475 −3024.27 × 100 3475

error =¿

27

30

 Temperature (°!

56.785 9

 Temperat ure vs. Velocity of sound

*N*)S#S O< &*T*

Velocity of sound in t/e rod 1Eu+tion

vr =

Υ   ρ

vr 4:

The data we gathered from the experiment shows that the sounds produced by the rod can be used to solve for the velocity of  sound that transmitted through the air inside the glass. The e(uation ) had a bigger   percentage error from the e(uation - due to that e(uation - only consist of two given data which is young’s modulus and the density of the rod. '(uation ) had a bigger 

33

 percentage error because it has many data that are not that accurate and that would need to be considered for the solving. roblems I’ve seen that it can be point out for that high error are the inaccurate measurement of the successive dust inside the kundt’s tube secondly is that the temperature of the room is one to be considered to be had an effect from the velocity of air and )rd the placement of the rod from the clamp. In successive demonstration we cannot think that the clamp can hold that excessive force from the  pulling back and forth of the demonstrator. Another to be considered from the e(uation ) that cause higher percentage error is the insufficient powder from the tube. It is not even from the whole tube and it sticks into the glass because of the moist. !or the e(uation -. /oung’s modulus and the density of the rod are all constant and that can be the significance of lower error. It only have 0 data to be considered to use so it can lessen the error. "ON"-S#ON

#e did determine the velocity of sound and the speed of it that was produced from the rod throughout the tube. #e manage to get that from manipulating some conditions that can produce resonance. 1onditions like that clamping of the rod at the middle so that we can have the wave and checking the rod and the disk inside if it was contact with the glass tube. This conditions were been

followed and by that we use the formulas given from the laboratory manual.  I there conclude that the longitudinal wave is produced as rod was pulled back and forth were the wave has e(ual fre(uency making a resonance. &ibration and the screeching sound was observe from that demonstration  produces sound that where visible wave  patterns inside the tube. As a method of imaging the Kundt’s tube was the medium used for us humans to see the idea of sound not only by hearing it but  by seeing it actually.

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I thanked my professor by sharing us many good experiences and knowledge from this sub2ect. And for the lab assistants that was giving us many techni(ues for us to do the experiment easily. I also want to thank my group mates who acts accordingly to our set tasks.

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