In order to truly understand what a ” pH ” means, one must first understand how exponents are used in mathematics. Afterward, the usefulness of logarithms, which are the opposite operation of exponents, will be greatly appreciated. Ten times one can be written as 10 X 1. Likewise, it may be written as 10*1. MostContinue reading “CHEMISTRY: Understanding The pH Scale”
Author Archives: George Walker
SOUND: Intensity, Loudness, and the Decibel System
The intensity ( I ) of a sound is quantitatively different than how sound is perceived by the ear. The perception of sound is referred to as ” loudness “. When a sound’s intensity increases by 10 decibels ( B ), the ear perceives this increase as a ” doubling ” in loudness. Logarithmic mathematicsContinue reading “SOUND: Intensity, Loudness, and the Decibel System”
SOUND: The Doppler Effect
Sound is a quantification of the rate at which pressure waves pass through a “ springy “ gas medium such as air. A complete wave cycle is inclusive of regions of high and low pressure created by a vibrating source of sound. If we consider a circumstance in which a stationary source of sound isContinue reading “SOUND: The Doppler Effect”
SOUND: Intensity As a Function of Distance From a Point Source
The First Law of Thermodynamics states that ” energy cannot be created or destroyed. ” Thus, the Wattage ( W ) in units of Joules per second ( J/s ), whether it be generated by an electric circuit, laser beam, ocean wave, falling skydiver ( drag force times drag velocity in W = Fv ),Continue reading “SOUND: Intensity As a Function of Distance From a Point Source”
SOUND: Beat Phenomena in Acoustics
Two major considerations will help us develop a clear understanding of an acoustic phenomena called ” sound beats “. First, consider that a longitudinal sound wave is a pressure wave moving through a ” springy ” medium. The Bulk Modulus and temperature of the medium influence the velocity of sound waves. Of interest here, however,Continue reading “SOUND: Beat Phenomena in Acoustics”
SOUND: Open and Closed-Pipe Systems, and the Concept of Resonance Frequency
Before examining the physics of standing waves within pipes that are closed at one end, a review of systems within which both ends are open is due. Periodic motion is used to model the behavior of systems that are harmonic or cyclical in nature. Within the midst of turbulent high-tide waves crashing against a shoreline,Continue reading “SOUND: Open and Closed-Pipe Systems, and the Concept of Resonance Frequency”
SOUND: Open-Pipe Systems
A standing pressure wave can be established by sound waves within a pipe with both ends open as well as pipes with one closed end. When a single-standing pressure wave exists within a pipe, the frequency ( f ) of the sound emitted is regarded as being the first or ” fundamental ” sound frequencyContinue reading “SOUND: Open-Pipe Systems”
KINEMATIC EQUATIONS: What is the ball’s speed when it’s caught by the goalie?
Q: A soccer player kicks the ball toward a goalie that is 29.0 m in front of him. The ball leaves his foot at a speed of 19.5 m/s and at an angle of 33.4° relative to the ground. Find the speed of the ball when the goalie catches it in front of the net.Continue reading “KINEMATIC EQUATIONS: What is the ball’s speed when it’s caught by the goalie?”
KINEMATICS: What Initial Velocity is Needed to Propel a Projectile Over a Barrier?
Q: The highest barrier that a projectile can clear is 13.7 m, when the projectile is launched at an angle of 10.5° above the horizontal. What is the projectile’s launch speed? A: Recall that a projectile that travels in a curvilinear path has components of motion in the ( x ) and ( y )Continue reading “KINEMATICS: What Initial Velocity is Needed to Propel a Projectile Over a Barrier?”
KINEMATICS: How Far Will a Fired Projectile Travel?
Materials needed: ( 1 ) Spring-loaded cannon; ( 2 ) ruler; ( 3 ) timer The goal will be to determine how far a model cannon’s projectile will travel. First, we will theoretically determine the muzzle velocity ( vm ) of our model cannon. Position the cannon horizontally upon a table. Measure the vertical distanceContinue reading “KINEMATICS: How Far Will a Fired Projectile Travel?”
