# Yr 12 physics - simple harmonic motion

Discussion in 'Science' started by AshgarMary, Feb 8, 2012.

1. ### AshgarMaryNew commenter

I'm teaching this next week (as teaching practice) for the first time, introducing the topic and covering kinematics and energy changes (IB syllabus - no calculus). The students (with their regular teacher) completed 'circular motion' end of last term. I have 3 hours to cover the topics.

Are there any particular pitfalls or misconceptions that you think students will be bringing to the party that it would be useful to deal with straight away?

I'm planning to find suitable animations and so on to show them and also do pendulum experiment to find g. I was thinking about whether a small circus of simple experiments for them to deduce the acceleration proportional to - displacement relationship is worth doing and if so, any suggestions?

Thanks in anticipation!

2. ### AshgarMaryNew commenter

PS I have found a range of SHM experiments on the Nuffield/IOP site :

http://www.nuffieldfoundation.org/practical-physics/examples-simple-harmonic-motion

and wonder if they lend themselves easily to taking measurements or if there are hidden pitfalls!

It's a small class so I'm thinking of just the:

Simple pendulum

Oscillating water column

and the displaced trolley between two springs from this link:

http://www.nuffieldfoundation.org/practical-physics/introduction-simple-harmonic-motion

3. ### physics_suits_you

As an old Nuffield man, I can assure you that they used to work well! (I haven't followed your links, but those sites were being used by me upto 4y ago).
There is a really good link between SHM & Circular Motion which consists of projecting the shadow of an object moving in a circle (eg bung on a turntable) and comparing it directly with the shadow of a pendulum (horizontal trace) or a mass on a spring (vertical trace). I would start there to show how you are going to build on their current knowledge.
A great challenge is to have a pendulum (with dripping paint/ink/sand?) as the bob and move a sheet of paper under it at a constant speed - you should get a sine curve with a constant period. I've set that to Alevel groups and left them for 20mins - it gets the competitive/collaborative spirit going.(Get permission of the lab tec first - it can be messy!)
Good luck.

4. ### Geth

As a possible starter, give the definition of shm and then challenge them to explain how to make a car move with shm e.g. when is your foot on the accelerator and when on the brake, when do you change gear etc. Possibly put in the context of a Top Gear challenge...?

5. ### T34Established commenter

I don't know about that, but I think it is useful to point out why one should study SHM as opposed to other "shapes" of repetitive motion.

6. ### AshgarMaryNew commenter

I'm just looking at the assessment statements to make sure I'm covering everything and 4.1.1 says: "Describe examples of oscillations" - what do you think they mean by 'describe'?

The definition of 'describe' is 'give a detailed account' - should they cover description of the situation plus some comments about the displacement, amplitude, period etc.? Or is that too much? I don't want to overload the students! (SL level)!

I haven't found any IB exam questions that seem to relate to this.