Project topic is Measuring the speed of light using a microwave oven. *NOTE: the topic can be changed if you want to work on something different. (I'll provide other project ideas upon request)
This project has 4 parts and each part of these 4 has to be done in a separate word document.
First part is Experimental Design:
- Research the wave concepts that apply to this sound device and submit a brief proposal that includes your understanding of the physical principles and your experiment design.
- Your design might be to arrange five identical glasses filled with different amounts of water. Measurements will be made using an app on your mobile phone, and a ruler. These will be related by the formula for a closed tube.
- Make some predictions about the experiment results. Using your understanding of the physics, you can make an hypothesis about the resonance frequency and relative loudness from each glass, depending on how much liquid is in it.
Second Part is Experimental Data:
- Perform this experiment by building the glass harp, filing the glasses with the amount of liquid you decided to use.
- You can then take several pictures of your experiment set-up, too.
- Measure the tones that are produced when you run your finger around the rim and record the data.
Third Part is Project Analysis
- Graph your data. Show uncertainty estimates for your measurements and discuss sources of error (e.g. uncertainty in the ruler, positioning of the microphone).
- Analyse the results by comparing your measured results to your hypothesis for the glass harp. How closely do the measurements match the theoretical model?
Last part is Final Report
- Finally, you would use your analysis to make a final determination on the accuracy and reliability of your understanding of sound waves in a closed tube. You would make a short report summarizing all your work and reflecting on what you learned.
- If you want, you can make a short video of your experiment or of you playing the harp.
Explanation & Answer
Use these two ignore the first one
Topic: Sound Characteristics of a Glass (Sprite) Bottle Containing Water at Different
Sound is a vibration of particles propagated as an acoustic wave through media, that
is, air, solid, or liquid. Production of sound requires the particles of a given media to be
disturbed resulting in the vibrations. Therefore, it is good for a person to establish what is
producing sound. For example, blowing across the top of a bottle causes the air particles in
the bottle to vibrate thus producing sound. On the other hand, hitting the glass bottle with a
piece of wood causes the glass particles to vibrate thus producing sound. It is for this reason
that it is important to establish the primary source of the sound. The characteristics of sound
refer to the frequency, wavelength, period, velocity, and amplitude. These five properties can
be used to describe the sound produced by different media. This project investigates how the
length of the air column in the bottle affects the frequency and wavelength of the sound
Two models are employed when studying the resonant frequencies of sound in air
columns. These models include; waves for an open tube and a closed tube. The frequency of
sound in a tube depends upon the length of the air column, geometry, and the speed of sound
in air. In most cases, the speed of sound in air is averaged at 300 m/s. Also, the harmonic
waveform can influence the obtained frequencies and wavelengths. Reflection interference
occurs on either the open or closed tubes resulting in a standing wave that is characterized by
antinodes and nodes. Equations 1 and 2 can be used to relate the length of the tubes (air
column) and the wavelength produced for an open and closed tube respectively. Also, the
relationship between wavelength, frequency, and velocity is as shown in Equation 3.
𝐿 = 𝑛 2 , 𝑓𝑜𝑟 𝑛 = 1, 2, 3, 4, ……….……………..…………………….…….Equation 1
𝐿 = 𝑛 4 , 𝑓𝑜𝑟 𝑛 = 1, 2, 3, 4, …………………………………………….…….Equation 2
𝜆 = 𝑓 …………………………………...……….…………………..………Equation 3
The air blown across a bottle will be modeled as a closed tube and thus Equation 2
and 3 will be used in this project. The air blown sets the air particles in the column to vibrate.
The air particles usually vibrate at a given resonant frequency that can be measured using
specialized electronic devices. In specialized labs, a set up comprising of a tube, wave
function generator, a microphone, and wave illustrator are used to study the sound wave
To establish the relationship between the length of the air column (independent
variable) and Wavelength (dependent variable).
To establish if the sounds are produced at the same harmonic number, and if is the
case, estimate the harmonic number.
Apparatus and Equipment
Fig. 1: Frequency Measurement App (Accuracy = 0.0001 Hz)
Fig 2: Sprite Glass Bottle
Fig 3: Ruler (Accuracy = 0.1 cm)