This week we have some interesting demos and activities looking at circular motion.
Circular Motion and Bowling Balls
This simple video with a bowling ball and rubber mallet shows a ball moving at roughly constant speed but as a force is applied (it is hit with the hammer) it changes direction but not speed.
The force can be seen to be acting towards the centre of the circular path and this causes the ball to accelerate (change direction) but not speed up or slow down.
Also when the strikes of the hammer stop the ball moves along a tangent.
Episode 224: Describing Circular Motion
This resource from the institute of physics was written to introduce A Level physics students to circular motion but it sits nicely in the GCSE triple science framework, extending the previous work on forces. It describes a lovely series of demonstrations – try for yourself the one with the jelly - which should get your students thinking and developing their own ideas.
Although most will already know about whirling a bucket of water around without the water falling out, it still has to be done! The table at the bottom of page 2 would make a useful cut and stick activity where students have to match the force to the example. Teachers will appreciate the practical tips and the background notes on the physics involved.
Astro Academy: Principia
A wonderful collection of resources based around Tim Peake's mission. There are some videos files of Tim doing experiments on the ISS that you can analyse. The whole section on circular motion is here
Flying weightless
This article, written for GCSE level students, provides a good example of circular motion in action for “reading around the subject” and as such it would be useful to read as part of a piece of homework. Consider asking students to explain the article to an adult family member when they have read it. The adult then signs the homework diary to confirm that they have discussed the article with the student. The discussion will be worthwhile for all concerned and doesn’t require any marking.
Why Doesn't the Moon Fall Down?
The two cartoon characters in this short video clearly and convincingly explain Newton’s reasoning behind the circular motion of the Moon. Show it to your students if they are unsure about how satellites like the Moon orbit the earth.
Nuffield Physics: Questions Book V
It may have been complied in the sixties but this collection of practical ideas is highly recommended as a resource for you to use. It is included here for the suggestions on circular motion. For idea 5 use a rubber ball rather than stone and you have a great demonstration that you can use to discuss the variation in the tension as the ball loops the loop.