Unit Nine: Waves & Sound

Today we went over standing waves, natural frequency, and resonance. A standing wave is a wave that remains in a constant position. Natural frequency is the frequency an object wants to vibrate, it is determined by the object's shape and/or other characteristics. Resonance is the overall adding of wave energies. We also went over sound, sound is a longitudinal wave and it needs a medium. Sound is like any other wave and it's wave speed is measured by it's frequency multiplied by it's wavelength, or v = fλ. The published value of the speed of sound in the air at room temperature is 343 m/s. Right now in our classroom the temperature is 76˚ F. To convert the temperature from Fahrenheit to Celsius you use this formula, [(given Fahrenheit) - 32] × 5/9. So the temperature in the classroom in Celsius is 24.4˚C. The reason why we need to know the temperature is because to calculate speed of sound in the room you use this formula: 331m/s + Tc(0.6).

Today we used these cylinders to measure measure the wavelengths and speeds of different frequency in the room.