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[Jeremy McCreary]

Picked up this fun little book on Amazon. Have you seen it? It was one of several "activity books" written by Bernie Zubrowsky for the Boston Children's Museum, ©1989.



The emphasis is on learning about discovering how tops work through simple guided experiments with DIY tops. Zubrowsky clearly knew more than a little about top history and physics. And unlike me, he had a knack for explaining it in plain English. I'd put the target audience at 8 years and older.

Just some of the topics found in the book's 96 pages...

How to make simple tops from common household items — especially disposable dinner plates:


How to get consistent release speeds (for experimental purposes) with a rubber-band starter:


Factors affecting spin time — including CM height and mass distribution:


How to make interesting patterns and optical illusions at speed, with some Benham disks for the copy machine:


Overall, a great way to let young scientists probe the mysteries of the spinning top on their own.

[ortwin]

...

Thank you for showing us Jeremy. Especially the picture above reminds me of some ring tops I showed here, over the last few months.

[Jeremy McCreary]

Thank you for showing us Jeremy. Especially the picture above reminds me of some ring tops I showed here over the last few months.

C'mon, admit it — you read this book beforehand!

Many of the things I've learned about tops, I discovered on my own over 7 years of hands-on topmaking. Usually by screwing up. Many of those things turn up in this book, at least in passing.

[ortwin]

...

C'mon, admit it — you read this book beforehand!

...

Au contraire, mon chèr!
I think you did! Just look at what you made here.
It is the same mistake as in that picture from the book, the ring is above the spokes instead of below as would be better for longer spin times.
You corrected that here after you were made aware of your blunder.

[the Earl of Whirl]

Very nice!  Good discovery.  And it says it is a Boston Children’s museum workbook.  Sounds like it might have been written and published by a local individual.  Sadly, I don’t think we have any spin top people in the Boston area that could go and check out their spinning activities.

[jim in paris]

Au contraire, mon cher !

Ah ah ! Thats a good one ,ortwin !
we are a league of gentlemen

This book is a good find  by the way

Cheers and " santé ! "

Jim

[ta0]

I didn't recall the book having some of those interesting experiments. Thank you, I need to revisit it.
If you want to discover more books about tops, you should look into my bibliography  www.ta0.com/papyrus/papyrus.html
These are all books I own but I need to update it with half a dozen more.

[Jeremy McCreary]

If you want to discover more books about tops, you should look into my bibliography  www.ta0.com/papyrus/papyrus.html
These are all books I own (except, perhaps, Klein's book that I cannot find) but I need to update it with half a dozen more.

I've seen an impressive bibliography of yours, but maybe an old one. Will definitely have a look at that link.

[Jeremy McCreary]

I didn't recall the book having some of those interesting experiments. Thank you, I need to revisit it.

Of course, the experiments in the book can also be done with LEGO. Here's one corresponding to a page I shared above...

Q1: Both of the tops below have the same parts, CM height, AMI, and the same weight on the same tip. Which stays up longer from the same release speed?







A1: The darker green top, by 75 to 50 s — a 50% gain.

Q2: Why?

A2: Two reasons:
1.  The lime top has a significantly larger central TMI. And that increases its critical speed.
2. The lime top also exposes about twice the spinning surface area to the surrounding air. And for that reason alone, it likely sees more air resistance.

Which factor dominates? Guessing the drag, but can't be sure. Drag was also a confounding factor in the book's experiment, but to a lesser degree.

PS: The tops above also let you play with CM height, as you can slide their rotors up and along the central black axles. That was another experiment in the book.

[ta0]

A1: The darker green top, by 75 to 50 s — a 50% gain.
Q2: Why?
A2: Two reasons:
1.  The lime top has a significantly larger central TMI. And that increases its critical speed.
2. The lime top also exposes about twice the spinning surface area to the surrounding air. And for that reason alone, it likely sees more air resistance.
Which factor dominates? Guessing the drag, but can't be sure.

That's my guess too.
But in my supermarket, limes are usually dark green and lemons greenish yellow. 

[Jeremy McCreary]

In LEGOspeak, those colors are green and lime. I can't help it if limes were named after the wrong color!