Skip to main content

A PocketLab Experimental Analysis of a Yo-yo

Submitted by DaveBakker on Tue, 06/20/2017 - 22:20

The yo-yo, a toy with an axle connected to two disks and string wound on the axle, has been of fascination to many for centuries.  It also offers a perfect opportunity to study angular velocity when a PocketLab has been attached to it.  A graph of angular velocity vs. time of a yo-yo will require students to think carefully about the detailed behavior related to its motion.

Subject
Grade Level

Planning to jump out of a spacecraft 24 miles above Earth? Don’t forget your PocketLab!

Submitted by DaveBakker on Tue, 06/20/2017 - 17:53

Exactly 65 years after Chuck Yeager broke the sound barrier in a Bell X-1 aircraft,Felix Baumgartner did too, but not in an aircraft. He did it by jumping out of one. In a state of the art pressure suit, Baumgartner jumped out of a capsule dangling from a helium balloon that had reached the stratosphere, 24 miles from the surface of the Earth. Before deploying his parachute, Baumgartner reached a top speed of 833.9 mph.

Rotational Dynamics of a Falling Meter Stick

Submitted by Rich on Fri, 06/16/2017 - 19:29

There is a well-known problem in rotational dynamics that involves a meter stick.  The meter stick is held in a vertical position with one end on the floor.  It is then released so that it falls to the floor.  The end initially on the floor is not allowed to slip during the fall.  Students are asked to derive an equation that predicts the angular velocity of the meter stick just before it hits the floor.  The derivation involves many physics concepts including gravitational potential energy, rotational kinetic energy, conservation of energy, moment of inertia, and angular velocity, thus giv

Subject
Grade Level

Magnetic Field on the Axis of a Current Loop

Submitted by Rich on Thu, 06/15/2017 - 22:17

In this lesson students will find that a current-carrying loop can be regarded as a magnetic dipole, as it generates a magnetic field for points on its axis.  The figure below shows a diagram and the equation for the magnetic field B.  Derivation of this equation requries knowledge of the Biot-Savart Law, calculus and trigonometry.  But in this lesson we are interested only in comparing experimental results from PocketLab's magnetometer to the theoretical equation in the figure below.  More advanced students can consider derivation of the equation, if they wish.

Subject
Grade Level

A Quantitative Study of Helmholtz Coils

Submitted by Rich on Thu, 06/15/2017 - 22:05

These coils come in pairs with the same number of windings of wire on each of the two coils. In "true Helmholtz" configuration: (1) the coils are wired in series with identical currents in the same direction in each coil, and (2) the coils are placed a distance apart that is equal to the radius of each coil. When in this configuration, they produce a very uniform magnetic field that is directed along their common central axis.

Subject
Grade Level

Investigating the "Spinning Coin" (Euler Disk) Problem

Submitted by Rich on Thu, 06/15/2017 - 21:29

Most everyone has spun a coin on its edge on a table top, and many find the result quite fascinating.  The coin gradually begins to fall on its side while spinning, makes a whirring sound with increasing frequency the longer it spins, and then abruptly stops.  The Swiss physicist, Leonhard Euler, studied this back in the 1700's.  An educational toy, referred to as Euler's disk can now be purchased on-line and in hobby shops specializing in science.  Such disks have been carefully engineered to spin for a much longer time than a coin.

 

Subject
Grade Level