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Waves and Simple Harmonic Motion

How does a Rangefinder Work - Physics of Probeware

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Submitted by clifton on Tue, 02/19/2019 - 04:34

Introduction to Rangefinders

Rangefinders, sometimes called motion sensors or motion detectors are commonly used in probeware, camera autofocus, and robotics. Rangefinders operate on the principle of a time-of-flight measurement and consist of a transmitter and receiver. The transmitter emits a signal (ultrasonic or optical) then the receiver detects the reflection or echo of the signal. The amount of time between transmit and receive is called the time-of-flight and is used to calculate the distance to the reflecting object:

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3D Printed Pendulum for Simple Harmonic Motion

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Submitted by clifton on Mon, 07/09/2018 - 19:37

This 3D printed model demonstrates the physics of a simple pendulum that consists of a mass, m, hanging from an arm of length, L, and fixed at a pivot point, P. You can move the mass along the length of the arm to change the center of mass of the pendulum. If you displace the pendulum from equilibrium to an initial angle, θ, and release, the motion will be regular and repeat. This is an example of periodic motion also called simple harmonic motion.

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PocketLab/Phyphox Damped Lissajous Figures

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Submitted by Rich on Mon, 06/11/2018 - 20:33

Lissajous Introduction

Lissajous patterns have fascinated physics students for decades.  They are commonly observed on oscilloscopes by applying simple harmonic functions with different frequencies to the vertical and horizontal inputs.  Three examples are shown in Figure 1.  From left to right, the frequency ratios are 1:2, 2:3, and 3:4.  These Lissajous patterns were created by use of the parametric equation section of The Grapher software written by the author of this lesson.  You are welcome to use this softwa

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Maker Project: Voyager and littleBits™ Music Visualizer

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Submitted by Rich on Sun, 01/21/2018 - 19:49

It’s not always enough to just hear music.  Many of us enjoy visualizing it while listening.  4th of July fireworks are commonly synced to Sousa’s The Stars and Stripes Forever.   Concert goers see spotlights flashing to their favorite pop songs.  Modern home owners play their sound systems synchronized with Phillips Hue lighting and nanoleaf® light panels with a Rhythm module.  For many years, classic visualizers have di

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CloudLab Curve Fit Feature Preview: Inverse Square Law of Light

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Submitted by Rich on Fri, 01/12/2018 - 22:15

The ability to quickly match empirical data to well-known mathematical models is an essential feature in the analysis of experiments.  This technique is generally referred to as curve-fitting.  The up-and-coming, but not yet leased, CloudLab software from PocketLab provides an easy way to fit data to models including linear, quadratic, power, exponential, and logarithmic.  This curve-fitting can be done for any selected region of PocketLab data.  This lesson provides a sneak preview of this CloudLab featu

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LED Flame Lamp: Random or Cyclical Illumination?

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Submitted by Rich on Wed, 01/03/2018 - 19:00

Late in 2017 a handful of companies began selling LED flame lamps that do a great job of simulating an actual burning fire. The illumination is bright, has a color temperature of a warm orange flame, and the light produces negligible heat while running at under 5 watts of electric power. This light seems to be a great replacement for traditional gas lanterns, hurricane lamps, and oil lamps.  The simulated flame is unbelievably realistic in the flame light purchased by the author. No obvious pattern could be detected in the flickering LED flame by observing the light with the eye.

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PocketLab Voyager Quantitative Experiment: Standing Waves on a Suspended Slinky

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Submitted by Rich on Thu, 11/02/2017 - 21:00

In addition to being a fun toy, the “Slinky” is commonly used in physics classes to qualitatively investigate a variety of wave properties: longitudinal versus transverse traveling waves, superposition of waves, wave reflection from a solid barrier or a free end, and standing waves and resonance.  Many of these investigations work well when the Slinky is stretched out on the surface of a floor.  However, to do a quantitative study of standing waves and resonance, suspending the stretched Slinky from the ceiling offers the advantages of less fricti

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PocketLab Voyager: Vibrating Meter Sticks and Music Boxes

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Submitted by Rich on Mon, 09/11/2017 - 17:38

The physics of the sounds produced by music boxes is definitely worth studying in curricula based upon NGSS (Next Generation Science Standards).   The prongs of a metal music box comb and an oscillating meter stick that overhangs a table are both examples of cantilevers--long projecting beams that are supported only at one end.  Other common examples include many suspension bridges, beams that support balconies on high rises, diving boards, airplane wings, and flagpoles mounted to the side of a building.

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Voyager & Ozobot: A Quantitative Experiment on the Doppler Effect

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Submitted by Rich on Mon, 09/04/2017 - 19:10

In this lesson we develop a laboratory experiment in which students quantitatively verify a major theoretical equation for the Doppler Effect when the wave source is at rest with respect to the medium and the observer is moving through the medium.  The waves are simulated waves on an iPad or similar device.  Ozobot keeps Voyager moving at a known speed, either toward or away from the wave source.

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