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AP/College

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:

Grade Level

Physical Pendulum: Finding Moment of Inertia

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Submitted by Rich on Tue, 02/12/2019 - 18:22

Introduction to the Physical Pendulum

Mount any rigid body such that it can swing in a vertical plane about an axis passing through the body.  You have constructed what is known as a physical pendulum.  The video below shows an example of such a pendulum.  In this video, a rigid circular body is swinging about an axis very close to the edge of the circle.  The circle was cut from a piece of cardboard.  PocketLab Voyager is resting at the bottom of a ring stand directly below the pivot point of the pendulum.  A tiny magnet has been attached to the bottom of the ci

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Grade Level

Hysteresis with Rubber Bands

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Submitted by Rich on Wed, 02/06/2019 - 17:49

Introduction to Hysteresis

Hysteresis can be defined as a lag time in the response of a system to forces placed on the system.  The response of the system depends not only on the present magnitude of the force but also on the previous history of the system.  From the point of view of mathematics, the response to the force is a double-valued function.  This means that one value applies when the force is increasing, while another value applies when the force is decreasing.  A graphical plot of force and re

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Grade Level

How does a Pressure Sensor Work - Physics of Probeware

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Submitted by clifton on Wed, 02/06/2019 - 17:02

Introduction to Pressure Sensors

Pressure sensors are one of the most widely used sensors and can be found in probeware for lab measurements, but more commonly in billions of devices including smartphones, wearables, automobiles, drones, weather centers, and medical instruments. Pressure sensors were one of the first sensors to be miniaturized and mass produced at a low cost through microelectromechanical systems (MEMS) fabrication.

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Grade Level

Rotational Motion: Moment of Inertia

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Submitted by Rich on Thu, 01/24/2019 - 20:05

Rotational Motion and Moment of Inertia Lab Setup

Figure 1 shows a ramp and three distinctly different objects that you will release from rest at the top.  Each object will roll downward to the end of the ramp without slipping, resulting in rotational motion.  The roll of Gorilla tape has a shape known as an annular cylinder.  The can of jellied cranberry sauce is a solid cylinder.  The cardboard tube, in contrast to the can, is hollow.  All three of these objects will rotate about their central cylinder axis while rolling down the ramp.  Each of these three objects has a

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Grade Level

PocketLab Voyager: Newton's Law of Cooling

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Submitted by Rich on Thu, 01/03/2019 - 03:02

Newton's Law of Cooling

In this experiment students will use PocketLab Voyager to collect data related to the cooling of a container of hot water as time goes on.  Sir Isaac Newton modeled this process under the assumption that the rate at which heat moves from one object to another is proportional to the difference in temperature between the two objects, i.e., the cooling rate = -k*TempDiff.  In the case of this experiment, the two objects are water and air.

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Grade Level

Fluid Pressure in a Fluid at Rest

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Submitted by Rich on Fri, 12/21/2018 - 01:22

Introduction

In a PockeLab lesson entitled "Hydrostatic Pressure Lab", posted by kwarnke in October 2017, students investigate the relationship between the height of a column of water and hydrostatic pressure.  The lab results worked very well in this regard, but the apparatus uses a 5-gallon jug with modifications, a bicycle pump, and 5 meters of vinyl tubing.  We should be able to come up with a much simpler and less expensive fluid pressure apparatus to achieve the same result, as the

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Grade Level

Terminal Velocity vs Area of a Falling Object

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Submitted by Rich on Tue, 12/04/2018 - 00:22

Terminal Velocity Introduction

The effect of mass on the terminal velocity of an object falling in air is commonly done using basket coffee filters.  But how could we study the effect of area on the terminal velocity of a falling object?  One way to do this is to use PocketLab Voyager and its range finder along with a single piece of cardstock as the object to be dropped.

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Grade Level

Energy Conservation with a Mini HotRod

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Submitted by Rich on Thu, 11/29/2018 - 22:16

Introduction

What can you do with a PocketLab Mini HotRod, Voyager, five pieces of HotWheels track, and a half-dozen wood blocks about the size of Jenga blocks?  How about an experiment in energy conservation!  Add CloudLab and you have an environment for your students/lab groups to perform, analyze, document and save their PocketLab lab reports.

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