# The Naked Scientists Forum

### Author Topic: What happens to the energy when dominoes fall over in sequence?  (Read 13796 times)

#### Alan McDougall

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##### What happens to the energy when dominoes fall over in sequence?
« on: 26/09/2008 11:58:58 »
Hi  People of the forum

Kinetic nd falling dominoes

Scientists define energy as the capacity to move mass or do work. You cannot make it and you cannot destroy it; but you can change it from one form to another and you can move it around.

A line of falling dominoes is a good example of energy moving from one place to another. A force (your finger) topples the first domino.

The force of the falling domino topples the next and the next on down the line. Besides converting all potential energy to kinetic energy, a transfer of energy has happened.

The record for the most dominoes toppled is 3,847,295 (from a possible 4,000,000). The attempt was organized by Endemol Netherlands and took place at FEC EXPO, Leeuwarden, Netherlands, on 15 November 2002, as part of Domino Day 2002. It took 100 builders working 8 hours a day between September and November to create the domino display.

Now my question is how can the tiny tap or light brush of of a finger to topple the first domino be sufficient to topple 3, 847 295 dominoes?. Surely the accumulated energy must be fairly large!!

Take Care

Alan
« Last Edit: 27/09/2008 22:46:40 by chris »

#### BenV

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• Posts: 1503
##### Re: What happens to the energy when dominoes fall over in sequence?
« Reply #1 on: 26/09/2008 12:03:13 »
I think the amount of energy transferred from your finger is actually quite small, and the dominoes actually fall due to the 'gravitational potential energy' to use a pre-GCSE physics phrase.

#### Alan McDougall

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##### Re: What happens to the energy when dominoes fall over in sequence?
« Reply #2 on: 26/09/2008 12:07:06 »
BenV

I like your answer , maybe others will come in with their take.Thanks

Take Care

Alan

#### lyner

• Guest
##### Re: What happens to the energy when dominoes fall over in sequence?
« Reply #3 on: 27/09/2008 00:27:39 »
If a domino has a mass of 10g and its Centre of Mass falls by, say 2cms, that represents about 0.002J of Gravitational Energy, a little of which is used to topple the next domino (you have to raise the CM of the next tile a bit before it will fall over and some Kinetic Energy will also be transferred) and most of which goes into the sound and some heat.
The only energy which the last domino will have will be a little bit more than the first because of all the losses as the impulse passes along the chain. The speed of the impulse increases for the first few dominoes but quickly reaches a steady value when losses balance the rate of energy transfer.
A Domino Powered Car might not be very powerful.

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##### Re: What happens to the energy when dominoes fall over in sequence?
« Reply #3 on: 27/09/2008 00:27:39 »