Physical Science 20
RESONANCE SPEED OF SOUND LAB
Your data and analysis section must include all your measurements and all your calculations. Show all your work, and
messy labs will be handed back to be redone.
Purpose: To find the speed of sound in air using the principle of resonance.
You will need:
A tuning fork, a rubber mallet, a resonance apparatus (a long cylinder tube, a rubber tube, a cup with a hole in
the bottom, a stand with a rod, a tube clamp, a ring clamp, and a meter stick), and water.
The length of the resonance tube can be adjusted by raising and lowering the water reservoir, which changes the water
level on the tube, effectively changing the length of the tube.
Procedure:
1. Choose your apparatus.
2. Place the cup at the bottom of the stand and add water to the cup until it is full.
3. Move the cup to the top of the stand and allow the water to adjust in height in the clear tube.
4. Using the rubber mallet or the sole of your shoe, strike the tuning fork and hold it near the top of the tube at a
90° angle (or the best you can manage).
5. While the fork vibrates, adjust the water level in the tube by lowering the cup. Make qualitative observations
here.
6. Listen for how many resonance points there are (when the tuning fork is loudest). This may prove difficult if
everyone in the class is at this step at the same time, so be patient.
7. Repeat step 4 and 5. This time, obtain quantitative observations (accurately record the exact length of the
water to the nearest mm at each point of resonance). This may require some fine adjusting skills as the water
does not adjust in height instantly. You may need to repeatedly strike the tuning fork while searching for these
points. Listen carefully, as you are performing this lab at the same time as others in the class.
8. Record the frequency of your tuning fork (engraved on the side) as well as the temperature of the room (located
at the front of the class tied to a string).
Observations:
Be sure to record all qualitative and quantitative observations neatly and accurately.
qualitative observations – the senses – sight, sound, touch, taste, smell
quantitative observations - all measured and calculated numbers
Analysis (show all your work in a neat and organized manner):
1. Calculate the change in length of the tube between each point in resonance (you should have at least 3 points of
resonance). Since you cannot be certain of which overtone the wave is resonating in, you must calculate the
wavelength of sound using the change in length values.
Here is why:
if you actually start at the fundamental  𝐿 =
And then the next is overtone #1  𝐿 =
3𝜆
4
𝜆
4
then the difference between the two measurements is: ∆𝐿 = 𝐿2 − 𝐿1 =
𝜆
3𝜆
4
𝜆
−4
∆𝐿 = 2
To reiterate, this method is needed since we do not actually know for certain which overtone corresponds with
the exact frequency of your tuning fork for your first measured length.
2. Find the wavelength for each change in length.
3. Find the average of these wavelengths.
4. Substitute the average wavelength into the wave equation to find the speed of sound in air. This will be your
value of the speed of sound.
5. Calculate the accepted value for the speed of sound at room temperature using the formula given in class.
6. Calculate the percent difference between your value and the accepted value with this formula:
% 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 =
|𝐴𝑐𝑐𝑒𝑝𝑡𝑒𝑑 𝑣𝑎𝑙𝑢𝑒 − 𝑌𝑜𝑢𝑟 𝑣𝑎𝑙𝑢𝑒|
× 100%
𝐴𝑐𝑐𝑒𝑝𝑡𝑒𝑑 𝑣𝑎𝑙𝑢𝑒
Your conclusion should summarize your entire lab and explain what you did, why you did what you did, and what
your results actually mean. Are they the results you wanted? What does percent difference actually mean for scientists
(look it up)? How does your percent difference compare the speed of sound through the principle of resonance versus
the speed of sound based on temperature? Accurate results should yield a percent difference value of less than 5%. Was
your percent difference less than 5%? If not, what could have gone better or what would you have changed to make this
a perfect experiment (also answer this if your value was less than 5.00%)?
You have one week to complete this lab. Submit 1 lab per group of 3, no other exceptions without speaking to your
teacher first.
Teamwork and deadlines are very important in the scientific community. Keep science happy and follow the rules.
Lab Write-Up Format
THIS OUTLINE WILL HELP YOU TO WRITE OUT YOUR LABS.
There may be changes or modifications but all elements must be included in your lab write-up. Each section on
your lab paper must include a heading (as in Purpose: )
I. TITLE: Separate front page, as given in your text book, handout, or by the teacher. Ensure you provide your
name, date, class, block, and teacher’s name in the bottom right hand corner.
II. PURPOSE: Sometimes referred to as the "PROBLEM" in the text, handout, or by the instructor. This will
be a short description of the purpose of the lab answering the question: "Why are we doing this lab?"
This is also where you explain some of the theory that you are about to test out. Where do the equations come
from and what do you hope to prove with them.
(marked out of 2)
III. THEORY: A brief explanation (1-2 paragraphs) of the principles in physics or chemistry that you are about
to investigate. Use diagrams where applicable.
(marked out of 3)
IV. MATERIALS: This is a recipe list of the materials that must include size, shape, color, and quantities used
in the lab.
(marked out of 1)
V. PROCEDURE: Written out step-by-step instructions referring to all materials, times, etc. to be used in this
lab. A proper procedure is written in a manner that would allow someone to reproduce your exact lab to the
exact detail. DO NOT COPY THE PROCEDURE PROVIDED FOR YOU. You may summarize it but be
specific for what you actually did in your lab.
(marked out of 3)
VI. OBSERVATIONS / DATA COLLECTION: There is always some kind of data that needs to be taken
down during an experiment. This section includes the notes you collect like the times, temperatures used, mass
quantities, the good things that happened and the bad. If possible, data should be in a graph or chart.
Sometimes data tables will be provided for you.
(marked out of 6)
VII. ANALYSIS
This is where the calculations and graphs go.
(mark varies on each lab)
VIII. ASSIGNED QUESTIONS: Answer all questions in the procedure of the book or any of the additional
questions at the end of the lab that the instructor assigns. Often the questions are set up to help when you are
thinking about your conclusions. (may not be in every lab)
(mark varies on each lab)
IX. CONCLUSION: THE MOST IMPORTANT PART OF THE LAB!!! This is a paragraph, or two, or more
depending on the magnitude or the lab, that tells the reader what you learned, or at the very least what you were
supposed to have learned but didn’t due to errors for whatever stated reasons. The errors must be the systematic
errors that you have no control over. “Measuring wrong” is not considered a reasonable source of error for any
lab. The conclusion will also be the place where recommendations are suggested for future improvements as we
as citing any relevant applications to the real world.
(marked out of 6)
Lab Report Rubric:
Name:
Hand in with lab
Date:
0
Not
present
Not quite
Purpose not clear or the
theory is not complete.
Getting there
Not
present
Errors in theory or
relevant equations are not
explained.
Not
Present
Missing materials.
Not
Present
Problem/
Purpose
Excellent
Clearly defined purpose with a
focused topic of study.
/2
Theory
/3
Materials
/1
Procedure
/3
Observations
/6
Analysis
Theory introduces the
topic and explains all the
necessary equations.
Theory introduces the topic and
thoroughly explains all the
necessary equations and the
rationale behind it all. (Diagrams
used)
All materials present.
Steps are there, but 3 or
more important elements
are missing.
Steps are there, but 1-2
or more important
elements are missing.
Specific and reproducible. (If you
gave this to someone to do, could
they do it?)
Not
Present
Missing either a qualitative
or quantitative observation,
or quantitative observations
are inaccurate.
Qualitative and
quantitative data are
present and correct.
Not
Present
No example calculations
shown, or work is very
sloppy, or the work is
completely incorrect.
Qualitative and quantitative
observations are accurate and
clearly organized using charts
where necessary.
All 6 parts are completed in a neat
and organized manner without
errors.
/6
Conclusions
/6
Format
/3
Not
Present
Far
below
grade
level.
Mostly completed or it is
completed but not in a
neat and organized
manner, or it may have
some slight errors.
Minimal:
Adequate:
Conclusion is there, but
Conclusion is adequate,
minimal link to original
the problem is
problem, application is not adequately referenced,
relevant, no sources of
application is vague, and
error listed.
only one source of error
is identified.
Many errors in format,
grammar or spelling, and
work is not neat.
Some errors in format,
grammar or spelling, and
work is mostly neat.
Effective:
Problem is answered (supported
or refuted) based on data.
Relevant application made. Future
improvements to lab are listed. At
least 2 sources of error are
identified.
No errors in format, grammar or
spelling, work is neat, AND a title
page is present.
Total
/30