Ernie McFarland University of Guelph
elm@physics.uoguelph.ca

This article first appeared in the OAPT Newsletter in 1987. It is being repeated here for three reasons: the demonstration is a classic, 1987 was a long time ago, and now this demo (and others) can be seen online (use the link at the end of the article).

One category of good physics demonstrations involves the “disorientation” or “disequilibrium” of students. The demonstrations in this category cannot be explained by most students, and thus serve to disorient the students into a state of disequilibrium from which they wish desperately to escape. Read More...

Tags: Forces

Bonnie Lasby, Physical and Engineering Science Dean’s Office University of Guelph
blasby@uoguelph.ca

This demonstration is a nice way to show that sound is vibration of molecules. The picture below shows the equipment required for this demonstration. The setup consists of an amplifier attached to an input device (laptop, iPod, mp3 player, etc) and a set of small speakers (described below) as well as a bar clamp and red and green laser pointers. Read More...

Tags: Waves and Sound

Forest Fyfe, Department of Physics and Atmospheric Physics Dalhousie University

This article is reprinted from Physics in Canada, Volume 65, No. 3, pg.141 (2009), with permission of the Canadian Association of Physicists (CAP).

Illustrating the concepts of centre of mass and centre-of-mass motion to an introductory physics class can be a challenge to a physics instructor. The topic can be very mathematically complex and is not necessarily intuitively obvious. A device that demonstrates how the centre of mass of an object moves as compared to the motion of a point on the object away from the centre of mass would provide an excellent qualitative illustration of this. At Dalhousie University we have constructed just such a device, our lighted throwing sticks. Read More...

Tags: Motion