IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Reference Material => GCE AS & A2 Level => Revison Notes => Topic started by: Saladin on November 25, 2009, 06:28:42 am

Title: Searle's Young modulus apparatus
Post by: Saladin on November 25, 2009, 06:28:42 am
Please give me a good animated version of he Searle's Young Modulus measurement apparatus.!!
Title: Re: Searle's Young modulus apparatus
Post by: MaNi_DaDuDe on November 26, 2009, 01:20:20 pm
Please give me a good animated version of he Searle's Young Modulus measurement apparatus.!!

http://www.tutorvista.com/content/physics/physics-iii/heat-and-thermodynamics/searles-apparatus.php

Just wait for it to load - if you have a slow internet connection.


[[EDIT]] :: This is just FYI.

Searle’s method for finding the Young’s modulus of a wire

Searle’s method uses two wires of the same material, one of which will be loaded with various weights.

E = \frac{F l}{A x}

E = (http://upload.wikimedia.org/math/d/e/1/de14524ee2421ac87d37804f5d14bd7a.png)

To calculate Young’s modulus we need to know:

    * The cross-section area of the wire (A). This is measured by using a micrometer to determine the radius of the wire, and then using the formula area of circle = ?r2. The radius must be measured in metres, and is typically 2 x 10-4 m. This gives an area of 1.26 x 10-7 m2.
    * The length of the wire (l, measured in metres).
    * The force and the extension.
    * The weight of a 1 kg mass is 9.81 N.

We plot a graph of the extension (m, horizontal axis) against the weight (N, vertical axis).

The gradient of this graph (change in vertical measure / change in horizontal measure) is the ratio F/x. If we multiply this ratio by l and divide by A we have the Young modulus for the wire.

Measuring the extension:

The ‘business end’ of the apparatus is a device which holds the two wires parallel, and allows the extension of the loaded wire to be measured.

(http://upload.wikimedia.org/wikibooks/en/8/85/Searle%27s_apparatus.gif)


Searle's apparatus for measuring Young modulus.

You need to label this diagram to show:

    * Constant mass attached to stress the reference wire.
    * Variable mass attached to stress the test wire.
    * Flexible connectors.
    * Level reference from one wire to the other.
    * Thumbscrew with scale to level the reference.
    * Clamps for wires.
    * Reference wire.
    * Test wire.

Advantages of this apparatus:

    * Thermal expansion of the test wire is correct by thermal expansion of the reference wire.
    * Long, thin wires allow maximum extension for minimum force.

Problems:

    * Difficulty measuring the cross-section area.
    * Extensions very small.
    * Mass, not weight, is measured.
    * Need high, secure mounting point unless apparatus adapted.
Title: Re: Searle's Young modulus apparatus
Post by: Saladin on December 03, 2009, 12:44:31 pm
you get this stuff if u type searle's apparatus in google, i wanted a good and labelled diagram of it.
Title: Re: Searle's Young modulus apparatus
Post by: MaNi_DaDuDe on December 04, 2009, 05:24:51 pm
Uh. You asked for :

Please give me a good animated version of he Searle's Young Modulus measurement apparatus.!!

So I posted an ANIMATION/video about it.

http://www.tutorvista.com/content/physics/physics-iii/heat-and-thermodynamics/searles-apparatus.php

Just wait for it to load - if you have a slow internet connection.


Plus I have no clue about this subject so it was just my 2 cents.

pz
Title: Re: Searle's Young modulus apparatus
Post by: Saladin on December 04, 2009, 08:04:14 pm
its not the apparatus i want. it is an appartus for thermodynamics, i wanted the one that can measure the extension of a wire.
Title: Re: Searle's Young modulus apparatus
Post by: MaNi_DaDuDe on December 04, 2009, 08:04:55 pm
its not the apparatus i want. it is an appartus for thermodynamics, i wanted the one that can measure the extension of a wire.

No idea then. ;)

Google's your friend.