The Naked Scientists

The Naked Scientists Forum

Author Topic: Why does my weight apparently differ when measured on different floor surfaces?  (Read 7946 times)

Offline standalone

  • Jr. Member
  • **
  • Posts: 37
    • View Profile
I have a small analog weighing device in my home which can weighs up to 100kg.It shows my weight to be 70kg in the hard surfaced floor but amazingly  ??? it shows my weight to be 74kg on the soft carpet. The weight on the soft body should be less but it shows the same everytime.

I checked on the pillow, spoon but they're giving lighter than in hard surfadce. I wonder what is happening?


[STANDALONE - PLEASE ENSURE THAT YOUR THREAD TITLES ARE PHRASED AS QUESTIONS, IN-LINE WITH FORUM POLICY. THANKS. CHRIS.]
« Last Edit: 28/12/2009 12:25:54 by chris »


 

Offline Chemistry4me

  • Neilep Level Member
  • ******
  • Posts: 7709
    • View Profile
Last time someone asked this, dunno if there's an answer though: http://www.thenakedscientists.com/forum/index.php?topic=15594.0
 

Offline standalone

  • Jr. Member
  • **
  • Posts: 37
    • View Profile
Actually i'm asking the reasons why weight increases in carpet? ???
« Last Edit: 28/12/2009 09:43:30 by standalone »
 

Offline standalone

  • Jr. Member
  • **
  • Posts: 37
    • View Profile
I think i have find out the answer for this question.

when the weighing device is kept on the carpet then the weighing device sinks little,the reaction due to our mass reacts on the weighing device from different directions  ,curving nature of the reaction force. thus, reaction concentrating on a single point causing it to show slight high weight.
« Last Edit: 28/12/2009 10:30:11 by standalone »
 

Offline standalone

  • Jr. Member
  • **
  • Posts: 37
    • View Profile
PLz!!!!!!!!!!!!!!!!!!!!! some can approve it or give me a clear explanations for this question.
 

Offline Soul Surfer

  • Neilep Level Member
  • ******
  • Posts: 3345
  • keep banging the rocks together
    • View Profile
    • ian kimber's web workspace
The reason is due to the way that the scales are made and the way that the weight is transferred to the measuring spring or springs.

All weighing machines (Other than the balancing sort where weights are compared directly) consist of a set of levers connected to springs which stretch in response to the forces and this stretching (or compression) is measured by a device that presents the information to the user.  Now bathroom scales like the device you are using have a platform on which you stand and this requires several supports and levers to transfer the weight to the measuring spring.  Because the scales only move a tiny amount, these levers are very sensitive to precise movements.  Now the box that holds these levers rests on four supports on the floor  and on a flat hard floor all the forces of your weight are transmitted directly to the floor through these supports. That is the way that the machine is designed to operate accurately.  Now, if you put the machine on a carpet these feet sink into the carpet and some of your weight is taken by the flat base of the box.  This causes the box to bend slightly and results in the calibration of the scales changing.  Precisely how it changes depends on the way in which the scales are made.
« Last Edit: 31/12/2009 12:21:55 by Soul Surfer »
 

Offline standalone

  • Jr. Member
  • **
  • Posts: 37
    • View Profile
Does it happen only in carpet or either on other soft surfaces?
 

Offline Soul Surfer

  • Neilep Level Member
  • ******
  • Posts: 3345
  • keep banging the rocks together
    • View Profile
    • ian kimber's web workspace
The surfaces have to be soft enough to cause a redistribution of the loading from the scales being used on a hard surface
 

Offline Geezer

  • Neilep Level Member
  • ******
  • Posts: 8328
  • "Vive la résistance!"
    • View Profile
You should be able to confirm this with a simple experiment.

Obtain something extremely rigid. A concrete paver would be ideal, but a piece of 3/4 inch plywood would probably work too.

Put the paver or whatever on the carpet, then sit the scale on top. You should now weigh the same as you do in your bathroom.

I suppose you should also make sure the platform of the scale is level in both locations. You should be able to confirm that with a spirit level.

BTW, if this experiment does not produce the expected result, it would seem that your carpet is producing a gravitational anomaly, in which case it could be worth quite a bit on e-bay.
« Last Edit: 02/01/2010 18:50:29 by Geezer »
 

Offline GlentoranMark

  • Full Member
  • ***
  • Posts: 98
    • View Profile
Try standing on one leg, your weight should be half.
 

Offline standalone

  • Jr. Member
  • **
  • Posts: 37
    • View Profile
Try standing on one leg, your weight should be half.

have u tried it . That is foolish at all,it wont happen.are u cutting ur leg then somehow....
When u stand by one leg then that leg gets all weight.
 

The Naked Scientists Forum


 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums