At-Home Experiment
The Chiming Spoon
Believe it or not, there are many sounds that you
never hear. Bats, for example, can hear sounds
humans cannot hear. Some sound waves that we
Question
Does sound travel differently through
solids than through gases?
can hear never make it to our ears — they travel in
another direction through the air. Let’s see if we can
find out more about how sound waves travel.
StuFF You’ll Need
•a piece of string,
approximately 3 feet
(1 meter) long
•a piece of thread,
approximately 3 feet
(1 meter) long
•metal spoon
Things to do
1. F
ill in the Question, Research, and
Hypothesis sections of your lab report.
2. T
ie the middle of the string around the
spoon handle.
•optional items:
other types of “string”
such as kite string,
dental floss, fishing
wire, or yarn and other
metal items to hang on
the string
10.R
epeat steps 2–7, using another type of string.
Was there any difference in the sound? You can
also try hanging other spoons (larger or smaller)
or even other objects (such as a metal hanger
or cookie rack) from the string and listening if
the sound is different. See Figure 3. Record
additional observations in the Data section.
3. W
rap the ends of the string around your
fingers.
4. G
ently swing the spoon so that it bangs
into the edge of a table. See Figure 1.
5. W
hat does it sound like? Record your
observations in the Data section of your
lab report.
6. Now, insert your index fingers into your ears.
Figure 1
7. L ean over, and swing the spoon so it bangs
against the table edge again. See Figure 2.
Record any sound changes you noticed in
the Data section of your lab report.
8. W
rap the string around your fingers several
more times to make the hanging section
shorter. Repeat steps 4–7. Record any
changes you noticed in the Data section of
your lab report.
Figure 2
9. T
ry gently banging the spoon against
different surfaces (metal, wood, plastic) to
hear if it sounds any differently.
© Educational Insights
Figure 3
1
www.nancybscienceclub.com
Lab Report
Question
The Chiming Spoon
Find the question on the previous page and write it here.
__________________________________________________
Research
Procedure
Look up sound waves and acoustics online or in
the library. Write some facts you learned here.
Step-by-step, list what you did in this experiment.
(Hint: Check out the Things To Do section.)
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
Book or Internet site(s) you used:
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
Hypothesis
____________________________________________
____________________________________________
Based on your research, do you think you will
hear anything when you bang the hanging spoon
against the table with your fingers in your ears
(as shown in figure 2)?
____________________________________________
Data
____________________________________________
Record any observations you made.
____________________________________________
____________________________________________
____________________________________________
____________________________________________
Materials
____________________________________________
List what you used to perform this experiment.
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
____________________________________________
© Educational Insights
____________________________________________
2
www.nancybscienceclub.com
The Chiming Spoon
Lab Report
Conclusion
What is the answer to the question at the top of page 2?
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
Real world Example
Many underwater animals communicate
with each other using sound because
sound travels very well in liquids. Animals
use sound to find their mothers, to find
mates, or to find food. Human beings
make lots of noise underwater when they
drill for oil or use sonar to steer their
submarines. What effect do you think
human noise has on sea life?
Extra Credit
Look at pictures of human and animal ears.Notice
that animal ears are shaped to “capture“ more
sound waves. Tall hare ears and fox ears are great
examples of this. You can hear better by cupping
your hands around your ears to capture and
funnel more sound waves into your ears. Try it!
hare
© Educational Insights
3
fox
www.nancybscienceclub.com
Answer SHEET
The Chiming Spoon
Answers
Question
You probably heard a loud chiming sound when
you banged the hanging spoon against a surface
with your fingers in your ears.
Real World Example
Underwater noise pollution from humans may
create problems for animals to locate their
young, or to find mates or prey.
Explanation
Using a solid (the string/finger) to transfer the sound
to the ears, rather than letting it travel through a gas
(the air) to the ears, creates a chiming sound which
is noticeably louder in volume. There are two reasons
for the louder sound.
1. The string is a solid. The vibrating sound waves
made from the banging spoon travel up the string,
through the fingers and into the ear. Sound waves
are less attenuated (weakened) when they travel
through solids and liquids than through air. In solids
the molecules do not need to travel to vibrate the
next molecule and pass the wave along. Most of the
wave energy moves through the string and finger,
directly into the ear, and does not scatter in the air.
2. When waves pass from one material to another,
especially a very different one (solid to gas), a lot of
energy is lost. The sound waves are transferred to
different materials in their trip from the spoon to the
ear. Without the finger/string in the ear, the waves
go from spoon (a solid) to air (a gas) to the soft
tissues of the ear (a solid). These materials are very
different and a lot of sound wave energy is lost (is
actually reflected back into the first material) in the
transmission to the different material. When the
finger/string is used, the waves are transmitted along
more similar materials: spoon (solid) to string (solid)
to finger (solid) to ear (solid) and less energy is lost,
© Educational Insights
4
or reflected, in the transmission. When more energy
from a sound wave arrives at our ears, the noise
sounds louder to us.
The tone sounds different because some of the
lower frequencies of sound are lost when they travel
through the air. The string and finger allow those low
frequencies to reach our ear and it sounds different
— like a chime.
You may have noticed that your own voice sounds
different to you when played back to you via a
recording. When we talk, we are primarily listening
to sound that travels through our bone to our ears
(this is comparable to hearing the spoon sound
through the string/finger in our experiment). But
with a recording, the sound is getting to our ears via
air (from the speaker) and so some of those lower
frequencies don’t get to our ears.
Place your hands over your ears while talking
and note the change in the sound. Now you are
blocking the little bit of sound that does go out of
your mouth and reaches your ears via the air. You are
only hearing the sound that travels internally
and this combination of sound waves with a
greater proportion of low frequency sounds is
dramatically different.
www.nancybscienceclub.com