I want to try an experiment related to mechanics -- suggestions please

  • I
  • Thread starter VVS2000
  • Start date
  • #26
28
11
This is an experiment that they used to inflict on KS4 kids, when I was teaching. I never quite understood how it was supposed to be run and teachers used to bully the kids into believing that it was meaningful and that they could actually get results. We had a tray of kit, as described and the kids would have a happy ten minutes, whirling the masses around, hitting each other in the face by mistake and then writing up the experiment according to the teacher's instructions. The problem is that the situation is not stable. The restoring force is Mω2r and, with any value of Weight is either too high or too low to obtain a steady value of r. The experimenter has to beat this using skill, luck and imagination. Otoh, using a Force Meter instead of the selection of hanging masses can produce a measurable relationship between restoring force, r and ω. Using a motor with variable speed gives a chance of reasonable results. In fact, a potentially good investigation.
You can pick your weights more carefully. Did you try it yourself? Maybe 10 minutes isn't enough for the current population of students to master the hand-eye coordination required. I'd record their results and give them another 10 minutes and make it an experiment about how fast they mastered physical tasks involving their bodies. Maybe calculate the standard deviation of all groups results after 10 and 20 minutes.
 
  • #27
sophiecentaur
Science Advisor
Gold Member
25,008
4,742
I tried every experiment myself and there were some very good and some not. Yes, you can learn to drive even very dodgy equipment and get ‘results’ but the “hand / eye co ordination” that’s called for changes it from a Physics investigation to an investigation into the students themselves. We all notice the able ones who ‘get it’ and not the confused ones.
The angle of the conical pendulum is very hard to get stable and I defy anyone to get a whole class doing it well enough to get more than a ‘flavour’.
if the OP wants to get a useful document out of the exercise then something less hit and miss would be better.
imo, the behavior of a rigid pendulum is very reliable and a nice change from a mass on a string. Loads of possible data and manageable errors.
 

Related Threads on I want to try an experiment related to mechanics -- suggestions please

Replies
1
Views
2K
Replies
2
Views
2K
Replies
3
Views
2K
  • Last Post
Replies
1
Views
618
Replies
9
Views
1K
Replies
4
Views
3K
  • Last Post
Replies
5
Views
3K
Top