Looking for quality data from ticker time experiments (for quadratic regression analysis)

[neilparker62]

TL;DR Summary

Trying out quadratic sequencing and quadratic regression analysis

Hi

I'm looking for pictures of quality data from ticker timer experiments. Especially if you have samples of tapes showing free fall. I want to experiment with quadratic sequencing and quadratic regression analysis of ticker timer data. If you are so kind as to post a pic of your ticker timer tape, could you please include on it some kind of scale reference which enables me to measure distances on the tape. Otherwise just a pic of the tape is fine - I don't need the tabulated data since I will be drawing up my own tables. Thanks .

(Am asking here because the data sets and/or pictures of tapes I have found so far online are not very convincing).

 

[Tom.G]

Can't help but...
What is "ticker timer tape"?
Stock market ticker tape is the only one I've heard of.

 

[sophiecentaur]

What is "ticker timer tape"?

It's a rather outdated school demonstration / experiment in which a paper tape is pulled by a falling (or otherwise accelerating) object. Regular marks are made on the tape by a vibrating arm with a pin. I liked the class exercise because it's a very tangible demo of the relationship between s,a and t and kids tend not to manage to mess it up and they get results they can stick in their books.

 

[neilparker62]

It's a rather outdated school demonstration / experiment in which a paper tape is pulled by a falling (or otherwise accelerating) object. Regular marks are made on the tape by a vibrating arm with a pin. I liked the class exercise because it's a very tangible demo of the relationship between s,a and t and kids tend not to manage to mess it up and they get results they can stick in their books.

I wonder if you could create a precision ticker timer device using a laser to burn small holes (or just marks) on the ticker tape ? Don't know how accurate 'traditional' 50Hz or 60Hz ticker timer devices are in terms of their frequency ?

 

[neilparker62]

Here is a "traditional" ticker timer data set graphed and analysed on desmos.

https://www.desmos.com/calculator/nb7pnzzu47

 

[sophiecentaur]

Don't know how accurate 'traditional' 50Hz or 60Hz ticker timer devices are in terms of their frequency ?

The 'ticker' is mains driven. The accuracy is 'appropriate' if the tape lengths are measured with a ruler. As an exercise in graphing and analysis it's fine with plenty of system noise. I have no idea how much the tape will drag or stretch.
I wouldn't have thought that additional frills (laser marking etc) would be worth while as the rest of the equipment components (trolley and ramp) suit each other.
If you want better results then start from scratch with more modern tech but the thread title suggests that the errors are part of the exercise.

 

[neilparker62]

Re Mains (UK and other 50 Hz countries)

±1%

National Grid is obliged by its licence commitments to control the frequency within ±1% of 50Hz so it can fluctuate between 49.5Hz to 50.5Hz.

I think a pulsed laser could improve on this anyway. Re trrack and trolley, I'm not thinking along those lines I'm thinking only about a relatively heavy object in free fall. Heavy so that it's motion is minimally impeded by the 'paper trail' behind.

Above data set is from a "free fall" experiment and it's clear there are some problems with drag and/or frequency because the value of g (from regression) is quite a bit less than expected. But at least the data set showed reasonably constant "second differences" which is more than can be said for various other data sets I've looked at.

 

[sophiecentaur]

Re trrack and trolley, I'm not thinking along those lines I'm thinking only about a relatively heavy object in free fall.

If you want to get a 'good' value for g then I( wouldn't think that a moving tape would be a good idea. Tinkering with an already aged design won't produce worth while results. Search around for methods for measuring g and take your pick.

 

[neilparker62]

For the reasons you mention above, the ticker time experiment is a very good one for the classroom. So it might be worth putting some effort into modernizing it - perhaps along the lines I suggest with a laser. Or other electronic means. Accuracy can be improved without necessarily wanting to rival the CODATA value (9.806 65 m s-2)

Looking at various videos, it also seems that analysis techniques haven't advanced much. Students should definitely be putting their results on a spreadsheet and should be taught the basics of regression analysis. Ticker tape data should also be checked for constant second differences - something that is notably absent from anything I've seen. Video demonstrations show a calculation of acceleration based on v(t) at the end of the tape minus v(t) at the start of the tape. Then you look in between and the second differences are showing very obvious non constant acceleration.

Am thinking of writing an Insights article along these lines.

 

[Tom.G]

If you are going to use a LASER to mark the tape, that better be photo-sensitive tape! The power needed to mark plain paper will need much shielding to avoid skin and eyes.

Just sayin'.

 

[neilparker62]

Ok thanks - will google for that. Could be an interesting raspberry pi programming poject!

 

[neilparker62]

Sat through 25 minutes of this mostly in a total daze but I think it's more or less what we need. Just thinking for the ticker timer one could adapt the light gate to count perforations in ticker tape - presuming we can get perforated ticker tape!

A very eloquent young techie team!

 

[DaveE]

Kind of interesting from a nostalgic perspective. But why not use video analysis now that everyone has a smart phone?

https://www.fizziq.org/en/post/video-analysis-for-teaching-physics

 

[neilparker62]

Kind of interesting from a nostalgic perspective. But why not use video analysis now that everyone has a smart phone?

https://www.fizziq.org/en/post/video-analysis-for-teaching-physics

Well I did that using a couple of slow motion free fall videos I found. I can't say the results were very convincing. For example I used a pixel ruler to measure displacement data from the following strobed free fall:

https://techtv.mit.edu/videos/831-strobe-of-a-falling-ball

The value of g obtained was really low but perhaps I've got problems with the starting point or maybe the strobe frequency - which they don't mention. I guess MIT expects you to calculate it which I did (or attempted to do anyway).

https://www.desmos.com/calculator/c6ag71iso0

Also:



In both of these I measured at constant time intervals and expected to see constant second differences in the data sets. But this was not the case in either. Possibly this problem will go away if we use very high fps for the videos.

https://www.desmos.com/calculator/c6ag71iso0