# The Naked Scientists Forum

### Author Topic: It's Impossible !!!..but How Can I Clap My Hands ?  (Read 4840 times)

#### neilep

• Withdrawnmist
• Naked Science Forum GOD!
• Posts: 20602
• Thanked: 8 times
##### It's Impossible !!!..but How Can I Clap My Hands ?
« on: 07/02/2004 03:51:36 »
I once read an explanation of my conundrum (many years ago) but have completely forgotten the reasoning to this query.....Say your hands are 100 cm apart .When you start to clap your hands, they both have to travel towards each other of course.....at some point they will be 50cms apart, then 25, then 12.5, then 6.25 etc etc ad infinitum yes?....if the distance is always halved , how do the hands eventually meet ? surely even at their closest they will never touch cos the distance towards each other is halved infinitely.....*sigh*  I probably have not explained it well but hope you understand the gist of it......I'm sure it's a simple enough solution yes ?....please enlighten me !! aaaaaaargh !!!!

'Men are the same as women...just inside out !'
« Last Edit: 07/02/2004 23:12:14 by neilep »

#### pencilhead

• Jr. Member
• Posts: 38
##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #1 on: 07/02/2004 07:08:16 »
eeeh good question?  Hand meets in halves? You see when you are clapping you are um... lmao hehehe I dunno!  YOu enlighen us

#### Ylide

• Moderator
• Hero Member
• Posts: 905
##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #2 on: 08/02/2004 01:28:22 »
It's a logical fallacy.  Don't buy into it.

Your hands are not halving the distance with each successive movement, they are heading towards each other with a definite acceleration.  Given that acceleration and starting points of the hands, one can mathematically show the duration of the clap and the position of the hands at that clap.

This message brought to you by The Council of People Who Are Sick of Seeing More People

#### Quantumcat

• The Kitty Down Under
• Hero Member
• Posts: 894
##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #3 on: 10/02/2004 09:02:19 »
Hands move together with the same speed, not halved per each time period. So, it's the same distance each time period so the distance will run out in a given amount of time. If it was half the distance each time period they wouldn't meet. But you've noticed when you clap your hands you don't slow down as they meet then like, hardly move at all? If that was the case they wouldn't meet, but they do because it's not half the distance per given time period ...

Am I dead? Am I alive? I'm both!

#### neilep

• Withdrawnmist
• Naked Science Forum GOD!
• Posts: 20602
• Thanked: 8 times
##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #4 on: 10/02/2004 13:14:09 »
Thanks Jay, Thansk Erin.....I understand and appreciate your answers.

'Men are the same as women...just inside out !'

#### tweener

• Moderator
• Neilep Level Member
• Posts: 1144
##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #5 on: 10/02/2004 23:23:58 »
If your hands were halving the distance every second (for the sake of simplicity) they would be traveling with an exponential deceleration.  When you are clapping, they are accelerating toward each other or at least moving relatively constant velocity.  Not exponentially decelerating.

----
John

#### Ylide

• Moderator
• Hero Member
• Posts: 905
##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #6 on: 10/02/2004 23:57:30 »
My microbiology professor used this example in class today and I yelled at her.  She was talking about how when you're picking how much time you want to autoclave something, you're killing 90% of the organisms in the first 10 minutes, then 90% of the remaining ones in the next 10 minutes, and so on.  Then she used the hands-coming-together-by-halves example.  It was worse than when she tries to talk about chemistry.  Why are biologists so abstracted from real science?

This message brought to you by The Council of People Who Are Sick of Seeing More People

#### Quantumcat

• The Kitty Down Under
• Hero Member
• Posts: 894
##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #7 on: 11/02/2004 07:54:59 »
If you ever did any co ordinate geometry at school, you should remember the graph of a hyperbola. The most simple one is y = 1/x which is the half by half thing ... think about the graph, then think about the graph of y=x which is what really happens. I know you've already understood it but here's just one more example just in case :P

Am I dead? Am I alive? I'm both!

#### neilep

• Withdrawnmist
• Naked Science Forum GOD!
• Posts: 20602
• Thanked: 8 times
##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #8 on: 11/02/2004 23:46:02 »
Thanks again Erin, and Jay and also John too.....I feel completely at ease with the clapping of my hands now....cheers..Neil

'Men are the same as women...just inside out !'

#### The Naked Scientists Forum

##### Re: It's Impossible !!!..but How Can I Clap My Hands ?
« Reply #8 on: 11/02/2004 23:46:02 »

Login
Login with username, password and session length