Category Archives: Empty-purse Barefoot Experiment

arvind gupta: learners’ library on dvd

Of course, Arvind Gupta needs no introduction. However, if you must have one, then here is one version: Toying with science – Rasika Dhavse profiles Arvind Gupta, winner of the National Award for Science Popularisation.

Single handedly, he has done a million things for the propagation of science and quest for knowledge (in India) than many other erudite people, entire organizations and well funded random NGOs.

He has been compiling fantastic articles, films & books on very interesting ideas around history, science, teaching (and learning – is there any difference between these two at all?) etc etc and has delightfully put them together, giving the whole world on a platter dvd to the whole world – for a pittance (Rs. 100/- only).

Please buy the DVD.  I have read / studied / viewed most of the content via http over the past few years. The content is lovely. He must have spent months if not years on the compilation! What a religious scientific fervour! Well done, Arvind!

Many of the items are in ‘public domain’ – but, for some of the rest, they fall in the delectable gray area – Copyright? Copyleft?? All rights reserved? All rights wronged? All lefts righted? Or all rites actually reversed?? Sirs and madams, what else – I think the idea of Arvind is noble, all said and done!

Here’s a verbatim cut and paste of the promotional email from Nyla Coelho of TaleemNet (via Ramgopal Koneripalli) that I got: (and further down, details for payment)

“Dear all,

Arvind Gupta, as most know, has over the years single handedly and single mindedly put together resource and reference material for making learning fun and stress free. Most individuals with some concern or interest in education, atleast in India, have visited his website

Here is a treat for all from him packed into a single DVD titled Learning Library on DVD.

Written on it are:

1000 e-books on education, peace, environment, science, math and books for children

145 short films on toys from trash

Photo Plaza- 5500 photographs of 500 science models

Love of Live (Passions of a Japanese Teacher) a NHK Award Film

Do Flowers Fly (film based on Danger School)

Story of Stuff (9-million viewers)

Story of Bottled Water

A Few deeply inspiring TED talks on Education

Can anyone ask for more?

Modestly priced at Rs. 100/- including postage, it’s a treasure for free. [It is actually 100 +  25 for postage — ramjee]

Send your order along with postal address and payment to Arvind Gupta at IUCAA, Pune University, Ganeshkhind, Pune 411 007 Maharashtra.

Email: Phone: 020-25604602

(P.S.: kindly include bank collection charges if paying vide cheque)

Spread the news widely.

Nyla Coelho”

Details of payment mode below (pasted from Arvind’s mail):

“Yes, it would be much easier to transfer money through electornic Bank transfer.Rs 125/- per DVD (including 25/- for Speed Post)

Name of Account Holder: Vimala Pandhe
Name of Bank: Bank of Baroda
Branch: Senapati Bapat Road, Pune
Account No. 98060100000372
Nature of account: Savings Bank

Or else people can send me a cheque (at par) or D/D) payable to Arvind Gupta at Pune Address

Arvind Gupta
Pune University, Ganeshkhind, Pune 411007

Please encourage Arvind – buy the DVD. I am absolutely sure the cost of your acquisition (at Rs 100/- per disk image + Rs 25/- for postage) won’t  begin to compensate even a zillionth of the effort put in by Arvind.  Still, a token is well, a token. And, token gestures are important too.

Thanks in advance!

structure and interpretation of children’s toys

Pure joy! The pleasures of breaking open a contraption, studying what is it that makes it work – and finally, reassembling it. Fascinating.

For the past few weeks, at the erdkinder (junior) classes, we have been looking at various toys – analyzing among others:

  • Why have been designed they have been
  • What is interesting about the form-factor – how is this and the colours of the toys – are related to the enduser children…
  • What are the various aspects of ‘packaging’
  • What is minimalist (and functional) design
  • What are the various mechanical and moving parts
  • What are the various laws that govern the moving parts
  • What are the basics of safety
  • How to handle tools…
  • etc etc

The fact that the children have spent nearly an year with the basics of science and math at the high school levels does help.

The way we go about doing it is: We discuss the toy – how it is supposed to work, why it looks the way it looks  – just by looking at it. And then, we pass it around and take a call. And then, we open it and discuss. Layer by layer, children learn the HowTo and WhyOnEarth kind of ideas. 

We finally reassemble it – at the end of an hour of fun, that is!

We sincerely hope that this infection of HowAnythingWorksVirus is bad and virulent enough in our children, goading them to apply the wonders of  ‘screwdriver technology’ to just about anything at home!  May be they would infect you too! For example, yesterday, we discussed as to how to cut a sheet of glass with a pair of plain old scissors, would you want to know how?

May be we would make a few toys with some locally and cheaply available materials when we graduate to that point…

I almost forgot to tell you – Actually, we are planning to look at the Barbie dolls in the next session – more from the point of view how anatomy basics are seriously violated by them! We would also look at the diabolical targeted design and appeal of the aforesaid toy range. GI Joe will have to wait, not that it really does Mattel

The title of this post is shamelessly derived from the tile of  THE best computer science book ever written – ‘The Structure and Interpretation of Computer Programs’ – the whole book is available online –  given time and energy, I would love to work with the children borrowing ideas from this book.

But then, I also remember the um, old jingle saying: Man Schemes, God Lisps…  Oh, the pun of it….

fascinating experiment/demo on packing factor…

… or density or Life, if you will.

— begin —

A lecturer once reached behind the podium and produced a jar. He then filled the jar with big rocks and asked the class. “Is it full?” Unanimously, the class replied, “Yes!”

The lecturer then took a bucket of gravel and poured it into the jar. The small rocks settled into the spaces between the big rocks.

He asked the class, “Is it full?” This time there were a few in the audience holding back, but most answered, “Yes!”

The lecturer next produced a can of sand and preceded to pour it into the jar. The sand filled up the spaces between the gravel. For the third time, he asked. “Is it full?” Now most of the audience were wary of answering, but again, many said, “Yes!”

Then he brought out a pitcher of water and poured it into the jar. The water saturated the sand.

At this point he asked his audience, “What is the point of this demonstration?” One bright person raised their hand and responded, “No matter how full one’s schedule is in life, he can always squeeze in more things!”

“No,” replied the teacher, “The point is that unless you first place the big rocks into the jar, you are never going to get them in. The big rocks are the important things in your life—your family, your friends, and your personal growth.

If you fill your life with small things, as demonstrated by the gravel, the sand, and the water; you will never have time for the important things.

— end —

Off that fascinating website:  Crossroads of that lovable and wisdomful heretic ‘Brixman.’

teachers, vernier callipers

For the past few sessions, we (erdkinder and I) have been studying about measurements, precision, accuracy, error, terror ad infinitum. As part of this and with a view to addressing the ‘syllabus’ requirements of the eminently (in)evitable X std exams, the children have to study about Vernier Callipers, Screw gauges etc.

Now, I have always been fascinated by this ingenious concept of Pierre Vernier, but I recall that, when I ‘studied’ his wonderful ideas a few decades back, it was quite sad; my illustrious (then) teacher (RIP) ‘covered it’ without a clue, though the concept is fascinatingly simple. Same story got repeated during my baccalaureate studies too. Unfortunately, I realized it only later that all these folks merely taught because they were paid to teach, and NOT because, they loved to teach nor were they men/women who were fascinated by the world of  ideas. May be the reason is that teaching is such an underpaid job, in spite of it being exhausting and sometimes saddeningly thankless, and hence is mostly dominated by folks, who are/were otherwise ‘rejects’ from the ‘system’ – meaning, highly paid cushy jobs; or it may be that it is a sadly negative feedback system in which good folks can’t get in for various reasons – and the folks who are there in the system, have lost all enthu for life. Of course there are exceptions, but then I believe, exceptions only prove the general rule. This is not to say that I did not have good teachers and I have thusly a bunch of axes to grind – I have had my own delightful quota of exceptions but they were mostly outside of the walled gardens of acadummya. heh!

But, by and large, there is so much joy in teaching, learning and being with children (ah, the luxury!) that, if by some magical Poincare inversion, if teaching becomes the highly paid and most respected profession – then… the result would be a deliriously delightful future, what else, but may be am merely dreaming or better still, smoking marijuana!

Now for a commercial break! 🙂

Luckily, all teachers (‘adults’ in montessoriese) in NammaShaale are there because they either love children or love montessori education mode – and mostly & actually it is both,,, It is a pleasure working (and getting workedup) with them. Thank dog for small mercenaries, am not talking about the cutely brattish young fellers and fellerinas at the primary environment, though..

Getting back the rant…

Considering, how important this teachers’ role is in/for the society, it is amazing, but is true in general all over the world, that the status quo continues. Of course there was one significant exception – ‘Soviet’ Russia – which alas or happily so, is no more.

Is the concept ‘water find its level’ applicable and operative here? Would this theory help one understand this breed of abominable know men and women? Would this be the result of parents happily outsourcing the ‘education’ to the schools, as they think that, with transfer of genes (le vice?)  their contribution towards their children is over – except in the case of  buying the new, latest and improved Sony PSP? For all I know, my neighbour’s golden retriever only knows…

Pierre Vernier beckons.  He has been waiting patiently for my rant to end, and I respect him for that too!

The idea of any measurement is to allow to us to have a reasonable take on something to be measured – and that which is possible with predictable accuracy and precision. In a given scale (Ruler, that is – not very despotic, I hope) graduated in centi and millimeters, the minimum measurement (technical jargon: least count) that is possible would be 1 mm; this is also normally called ‘pitch‘ – but I intend queering it. Now, <drumroll> here enters the French man (actually he did this nearly 4oo years back) who decided to use a scale (vernier scale) that had ten divisions that were equal to 9 normal scale (‘main scale’) divisions. Hence each vernier division had a least measurement possibility of 0.9 mm.

Now comes the magic. If these two are brought together / juxtaposed then it is possible to measure lengths accurate to 0.1 mm. The least count of the combination of scales is 0.1 mm! How?

We worked with mere paper strips. I gave the children 2 strips each (some 1 cm x 10 cm – the size does not matter, dinosaurs notwithstanding – but we will call them A and An just to confuse you). One of the strips A was folded into 10 equal parts and marked off appropriately – the other strip An was placed over the first and was reduced/cut-off to measure 9/10ths of A. In other words Lengths of (A/An) = 10/9. An is also folded into 1o equal lengths and is marked off. All reasonably approximate of course.

A = mein skale. An = vernier scale.

Now, if you juxtapose them in such a way  that the markings face each other, Voila – at any point any ONE division mark of An will coincide/align with some division or the other of A – if you move A and An against each other! Yay! There is a picture of it below to befuddle you more!

how to understand 'vernier' using paper strips - you can move them against each other,,,

how to understand 'vernier' using paper strips - you can move them against each other,,, (the newspaper just serves as a background)

From this, it is a small baby step ahead, to understand how the magic works, nothing earthshaking, but beautiful! Of course, the children understood the cutting edge technology with a little bit of steering etc. I am proud of them.

If you are curious about how this concept works or if your engineer neighbore wants to know it, just go ahead and hustle any of our erdkinder. They will be happy to enlighten…

Erdkinder macht frei. Ja.

Experiment: You *are* powerful!

Did this experiment with the children, after I completed (and they assimilated, hopefully) the prerequisites. It was fun.  We climbed up and down the stairs of the over head water  tank – located at some 11 meters from the ground level.

We plan to have a couple of hours of discussion dealing with the subject, (with the children) and will post the details / feedback later.

The following text gives the ‘template’ for doing the experiment.


Prerequisites: Basic knowledge of what power, work and force mean.

Suggested Target group age band: Elementary – or as soon as children know how power and work are related – energy is the capacity to do work, that is.

Since, how to conduct and record properly formed / controlled experiments has been taught to Erdkinder, it is apt for them too.


  1. Understanding the units of work (Joules), force (Newtons), energy (Watts)
  2. To know how they are related
  3. What are potential and kinetic energies
  4. To explore whether there are other kinds of energies

Ingredients/Apparatus required: A stop clock (a wrist watch would do too); measuring tape/ruler; weighing machine; a few flights of stairs; children whose energies need to be taken out; the usual notebook and pencil.

Experimental procedure: Time how long it takes a child to walk up a set of flights of stairs; measure the height from the bottom to the top of the flights, If needed, measure the height of one step and multiply it by the number of steps.

Take the mass (not weight!) of the child (measure it with the weighing machine; wonder why it is called the weighing machine, though!).


Take the weight of the child in Newtons (mass (= in kgs) X g (= acceleration due to gravity – circa 9.81 meters x second-2 – for easy computation, you can use 10 meters x second-2)) and multiply the total height scaled. This would give the gain of potential energy by the child when he/she goes up.

The work done is in Joules – which is actually kgs X meters X second-2 X meters

Now divide this gain in potential energy by time taken (in seconds) to give the child’s power in Watts.

All children can do this computation. If there are issues of physical inabilities/disabilities, then the adult would have this child do the compute/time etc.


The children can take turns and measure their power – while one climbs up, the other can time it, etc.

It would be ideal if there are many flights of stairs, but if not one can try climbing the railings of over head tank or if this not available, may be one can even walk.

  • Driving home: Work done = force x distance moved in the direction of the force
  • Driving home: Energy is the capacity to do work
  • Driving home: Power is the energy transferred in a given time; or the capability to do energy transfer in a give time.

Effect: The linking of the text-bookish understanding of force, power and work to something concrete that all of us do on a daily basis. And, the fact that we can measure our power output in a fun way. Thusly, the power of wow!.

Questions for discussion: All thru the presentation, questions from children need to be positively encouraged; to elicit the opinions of children the following types of questions can be posed:

  1. What is your weight in Newtons? (mass in kgs x ‘accleration due to gravity’ in meters/second2)
  2. What would be your weight on say, Moon.
  3. Why can’t I measure the time of my coming down the stairs. (actually you can do that; the thing is there would be a decrease in potential energy and the force of the earth (gravitation) would help you unlike while going up)
  4. What happens when – I carry on my back someone else and walk up? Would he/she have done some work too? Is there a difference in energy of both? What about the power of the person carried?
  5. What could happen if there were no gravity? What would be the difference if we were doing the experiment on the moon?
  6. If the children run up the stairs as opposed to walking up, does it make a difference to their power? (can it be linked to the formula)
  7. If they carry an additional weight, would it make a difference to the power or the work done? To know this does something need to remain constant?
  8. Is there a connection between the power of the individuals and say incandescent bulb wattage ratings such as 100W or 60W or something? Do they actually measure the same? Are we talking about similar things here?
  9. In the same vein, is there any connection to the power output of the vehicles?
  10. If we use or expend/exert similar energy/power while riding bicycles as with walking or climbing, how come we go much faster for the same power output?

Eventually the children should be able to zero-in on the principles behind the effect on their own, but if not, they can be given clues and similar effects.

Closure: There should be definite closure to the demo – repeating and reaffirming the basic principle involved; can take the form of ‘Look, this is what I did and this is what happened. Do we agree that this could be a reason? What do you think happened? Was it <any of the (off tangent) suggestions from the children> or <any of the correct explanations>.’

This will close the activity at the class / environment.

Records / notes: These should be created by the adults for each instance of the experiment – typically as appendices to the same document so that ‘lessons learnt’ could be captured and disseminated later on. This could be some interesting diversions or some interesting questions etc etc.

Precautions: Safety first – the adult has to do the climbing at least once (to see if the stairs or slippery or corroded or whatever danger that could lurk in there) and if the railings are not safe, then walking on the road can be resorted to instead.

Children should not be allowed to crowd around the railing area. No need for any cheerleading or catcalls as this is a ‘scientific’ experiment.

Suggested activities: The children, as a way of reinforcing their learning, should do these; these typically could take the form of the following:

  1. Encouraging them to perform the experiment at home – for the benefit of parents. (may be)
  2. Conducting a quiz on the factoids (oral / written) the following day.
  3. Extensions that the children can be prompted to explore. Are kinetic and potential energies related?
  4. Can the child ‘increase’ its power output – if so how (stamina is the other word for power in the human context and so regular training would help – coupez la difficulte en quatre)
  5. Assuming that the kids do the timing/climbing everyday – can the children draw a graph showing how their power is increasing over a period of time?


  1. My impromptu experiments with a few adolescent children many years back. I think any self respecting physics book would cover this kind of experiments and therefore there is nothing major or new here at all.
  2. There could be quite a few websites dealing with the stuff. In any case, NO claims to originality are being made here. And we don’t claim any copyright either!
  3. The purpose of putting up this stuff is to enable others use the method or the madness, if they so desire.
  4. Please refer to the earlier post – these experiments can be done at home too!

Please feel free to comment on the content and style. Suggestions for improvement of the procedure  or feedback after using the idea are welcome.


Empty-purse Barefoot Experiments that make interesting demos in school or at home…

The basic Montessori curriculum has tonne loads of nice presentations and experiments (and Namma Shaale is well equipped with all these), and if only one has the time to sit with the children, he/she would be amazed at the kind of depth and breadth of knowledge any child has.

The framework attempted to be presented here is merely one of probably very many ways of adding more to the bucket, so that interesting activities can be done with the children, with a view to consolidating their ideas about the universe.

This document has to be read from the perspective of a non-montessori trained person, who means well, and who likes working with the enthusiastic and marvellous Erdkinder at Namma Shaale.

Your comments are most welcome.


Notes / preamble:

The idea is to document the various interesting experiments (that can lead to Aha! type discoveries by children – in sciences and humanities) which can be undertaken with a little bit of care and preparation – but with very little investment (if any) by way of equipment.

If an adult has sufficient resilience and some reasonable grounding in liberal arts, she/he would find it easier to do the experiments and elicit the opinions of the children – so there is no need for an erudite science expert or ‘resource person’ to deliver the fun ideas – as the idea of documenting these experiments is to dispense with these.

All along the presentation, the ‘stealing of thunder’ from children would sought to be avoided and the children would merely be nudged towards discovering the law or the principle behind what’s happening – provided they have the prerequisites in place.

The experiments need to be part of a framework (eventually) of experiments that all children need to be exposed to – at the level of Erdkinder. And by way of reverse integration, all these experiments have to link back to concepts / presentations made as part of the primary and elementary curricula in the school.

The time taken per experiment will vary between 15 mins to 20 minutes excluding discussions – but this has to be recorded and averaged as we collect more data.

All the experiments would tend the follow the following format – and there shall be one parent document per experiment.

Prerequisites: What are the things / nuggets of information that the children need to know before they can appreciate the experiment or the effect.

Suggested Target group age band: This would vary anywhere between primary to elementary to erdkinder – that is from may be 6 years to 15 years (and more). But this ageband criterion is not to be treated very strictly – if from the perspective of ‘readyness’ of a child or a given group the experiment would merit presentation, so be it.

Goal(s): What are the factoids that can be practically seen and verified by children and what are they expected to do.

Ingredients/Apparatus required: This set of items should be kept ready before beginning the presentation, unless an ‘effect’ is sought to be created in the minds of children, by ‘casually’ taking an otherwise dull and mundane thing or a set of objects and creating an Aha! situation.

Experimental procedure: This will be detailed and if necessary, should have diagrams.

Effect: The details of the experiment will lead to this and this will be rather cute or counterintuitive in most of the cases – to capture the imagination of the child. Or it is so common that we take it for granted, but the principle behind this is so very cute. So the effect should be able to clearly demo the principle and which is sought to be ‘discovered’ by children.

Questions for discussion: All thru the presentation, questions from children need to be positively encouraged; to elicit the opinions of children the following types of questions can be posed:

o Why – this prodding will work normally

o Why not – this kind of prodding will produce amazing results and will truly be real learning for adults too!

o What happens when – To make the children think about the given framework and what can be thought within the framework

o What could happen if / if not – These are gadenken experiments and children would enjoy these modes of questions; these are out of the framework or the basic context of the experiment.

Eventually the children should be able to zero-in on the principles behind the effect on their own, but if not, they can be given clues and similar effects.

Closure: There should be definite closure to the demo – repeating and reaffirming the basic principle involved; can take the form of ‘Look, this is what I did and this is what happened. Do we agree that this could be a reason? What do you think happened? Was it <any of the (off tangent) suggestions from the children> or <any of the correct explanations>.’

This will close the activity at the class / environment.

Records / notes: These should be created by the adults for each instance of the experiment – typically as appendices to the same document so that ‘lessons learnt’ could be captured and disseminated later on. This could be some interesting diversions or some interesting questions etc etc.

Precautions: The usual stuff – but that which cannot be ignored!

Suggested activities: These should be done by the children as a way of reinforcing their learning; these typically could take the form of the following:

o Encouraging them to perform the experiments at home – for the benefit of parents. (may be)

o Conducting a quiz on the factoids (oral / written) the following day.

o Extensions that the children can be prompted to explore.

Sources: Wherever possible there should be citations. We can also openly share our documentation.

Revision history:

$$ Created: 18th August;      ver 0.1    $$

$$ Revised: 15th December; ver 0.2    $$

Again, comments are welcome.