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Projectile Motion

The Rifleman’s Rule

Eric Haller, Secondary Long Term Occasional Teacher, Peel District School Board
eric.haller@peelsb.com

A couple of years ago I bought a bow and got into the sport of archery. To improve my accuracy at the range, I decided to invest in a laser rangefinder that could tell me the distance to my target, and its angle of elevation/depression. After using it for the first time, I discovered a third feature I was not aware of, the “Angle Intelligence™ Distance” (as it is referred to in the HALO OPTICS user’s manual). Interestingly, the rangefinder takes the angle of elevation/depression and the line-of-sight distance to the target into account, and calculates the adjusted distance to the target, as though I were instead shooting at a target across a perfectly horizontal field. Reading through the entire user’s manual, I couldn’t find any mention of what formula they used for the calculation, so I figured I would try working it out for myself. After a few hours of trying with a pen and paper, I discovered it was a lot more difficult of a problem than I had initially thought; so I turned to the internet. I eventually found the formula I was looking for; named the “rifleman’s rule.” The rule is fairly complicated to derive, however no part of the derivation requires anything beyond a grade 12 understanding of physics or math. This article will guide you through the derivation of the rifleman’s rule. You could work through it with your students, use this knowledge to help your school’s archery team, or even perhaps use it in the field yourself. Read More...

A New Look at Newton’s Laws of Motion

Roberta Tevlin, OAPT Newsletter Editor, Teacher at Danforth CTI
roberta@tevlin.ca

One of the standard parts of an introductory physics course is a study of Newton’s Three Laws of Motion. They are part of the Ontario curriculum for grade 11 physics and most teachers would agree that they are essential. Chris Meyer has presented an improved way to teach the three laws of motion that will deepen student understanding: Teaching Forces I and Teaching Forces II.

In this article, I hope to reinforce Chris’ approach with a look at how the history of these three laws is wrongly presented. Read More...

Spring Surprise: Projectile Motion made Fun, Mathematical and Real!

Roberta Tevlin, Editor, OAPT Newsletter
Roberta.tevlin@tdsb.on.ca
Edited by Tim Langford

Projectile motion often involves a lot of mathematical problem-solving that is overly simplified and highly contrived. Football players do not stop to calculate the range before making a pass. Invading armies might want to make calculations for siege weapons, but these tend to be too complicated (trebuchets) or involve too much energy loss (catapults). Guess and check, was probably the preferred technique. Fortunately there is a cheap and reliable projectile launcher that you can use to show that physics works. Your students will be able to use it to hit a target on their first shot by using calculations for conservation of energy and projectile motion. Read More...

GIFs in the Classroom

Eric Haller, OCT
rickyhaller@hotmail.com

It’s autumn, and maybe you’re looking for a new way to impress your physics students this semester. I find it easy to amaze my class by using various forms of technology in my lessons. Often our students don’t realize how tech savvy physicists need to be, picturing us using chalkboards to give lectures and not using supercomputers at CERN or developing video games which use physics simulations. Ok maybe I’ve never been to CERN or made a video game, but I can make my own GIFs. In this article I’m going to show you some GIFs you can use in your lessons, and also teach you how to make your own GIFs. Read More...

Energy and Motion Connections in a K’Nex™ Catapult

Margaret Scora, Teacher at Monsignor Paul Dwyer CHS
mscora@sympatico.ca

It is very important to have our students engaged in the classroom in order for deep learning to occur. Your students need opportunities to use their creative spark and build on their 21st century learning skills. Peter Benson’s TED talk does a great job of presenting how important this is.

Ideas for projects proliferate but many of these are time-consuming, expensive and beyond the skills of an average student and the tools of an average physics classroom. However, your students can build a catapult with K’Nex™ in just one class with virtually no prep and no trips to the wood shop.
Read More...

Water Rockets

Rolly Meisel
rollym@vaxxine.com

Having students construct and launch a water rocket is an entertaining way to investigate Newton's Third Law of motion. Students can construct the rockets at home for an in-class launching session. Read More...

D-Ball

Diana Hall, Bell High School, Nepean, Ontario
Diana_Hall@ocdsb.edu.on.ca

This is a very popular game I have played with my OAC physics class. It incorporates the concepts of conservation of energy and projectile motion. Read More...
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