[squeakland] Tour of Uruguay / Vuelta Ciclista del Uruguay

Carlos Rabassa carnen at mac.com
Tue Mar 1 12:14:57 EST 2011


David Corking wrote:

> 
> Carlos Rabassa wrote:
> 
>> May I answer the recent request for ideas for projects related to the
>> forthcoming Tour of Uruguay.
>> E042 - Understanding the Bicycle
>> https://docs.google.com/document/pub?id=19Dug-0DCk2520Fsx0hl-dzZDJp3cWVDWBDL-ik1Js14
> 
> Great projects.
> 
> I think 2 3 and 4 have straightforward answers from high school physics.
> 
> But the first project is very interesting but is much more difficult
> and controversial. It may be sufficient to have tested some
> hypotheses, without confidently discovering  "the correct explanation."
> 
> It could be a lesson in critical reading of scientific literature.
> 
> I think some links on this BBC page may help:
> http://www.bbc.co.uk/programmes/b00x3y2j


David,

thanks for your comments,  as well as the BBC link.

You touched a very interesting point on which I would like to hear from as many teachers as possible.


How to ask students to do an Etoys project?

How much to tell them?


In my non-teacher opinion,  just from all I hear,  I believe it is a key question.

We say too much an we ruin all the value of the proposed exercise.

We don´t say enough and the students might not get interested in trying and learning.

I issued a first theory that was obviously wrong.

It concluded we would always fall.

Experience tells us this is not true.

Then I tried to follow the steps of the scientific method and issue a second theory which I called "my" explanation.

I thought this was implying quite clearly it is just "my" explanation and not "the" explanation.




I imagine one of the many things students have to learn to do with this kind of exercise we proposed is to go one step beyond good reading comprehension,  maybe this is what you mean by critical reading of scientific literature.

In the real world there is no teacher to clearly state for us the problems we are expected to solve at work or in our families.



One of the things we said clearly when posing the question is we were assuming very low speed. 

Then we drew a very simple bicycle and drew a second sketch showing a perfectly vertical and straight front wheel fork.

Part of the work I was expecting the students to do was to state some limitations to simplify the problem.  

I just said low speed.  

I said nothing about the geometry of the bike,  just made a rude sketch.



There is a very simple experiment to get a feeling of the order of magnitude of the giroscopic effect in the bicycle wheels:

Remove the front wheel,  it´s usually quite easy to do.

Spin it at a rotation speed equivalent to the low linear speed we proposed in the problem.

Hold the two ends of its axle with your fingers.

Then try to move the wheel in different directions.

You clearly feel the forces but you can easily control them with your fingers.

Forces of that magnitude will do very little to help you keep your balance.




> I think 2 3 and 4 have straightforward answers from high school physics.

This raises another interesting question for teachers.  Would be nice to hear their comments.


You seem to assume the teacher will follow the method used in schools years ago,  when I was a student.

It is probably still used today.

A subject is discussed in class.

Then problems are proposed related to that subject.



Should we continue teaching this way?

Is this the way of teaching critical thinking we keep hearing when Etoys is mentioned?

You seem to imply the student will first learn math,  then physics and then he will try the bicycle problem.

Wouldn´t it be interesting to cause students,  maybe even very young ones,  to try to figure out some explanation.

Whether their explanation is right or wrong,  don´t you think those students would be learning?

Maybe at least learning how to draw a bicycle and in the process maybe discover some hints to find a solution to the problem we posed.

Maybe if they are asked to put their theories in writing,  they will practice writing.

Maybe if we propose they work in groups,  they can learn team work,  so useful in any real world work environment.


Thanks again for your comments.


Carlos Rabassa
Volunteer
Plan Ceibal Support Network
Montevideo, Uruguay





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