The values found were 0.57±0.02 for Poisson’s Ratio and 5±2GPa for Young’s modulus. Now that the issue regarding the units of measurement has been resolved, substitution of the measured values into Young's equation can be performed. Light waves from these two sources (the left side and the right side of the card) would interfere. Apply your understanding by interpreting the following statements and identifying the values of y, d, m and L. Finally, perform some conversions of the given information such that all information share the same unit. good and superb. All the results for the correct constitution have been summarised in Table IX. Both static and dynamic modulus methods are covered in this Guide, presented in separate sections with details on the different test methods and on practical issues affecting the quality and accuracy of the measurement. Use these measurements to determine the wavelength of light in nanometers. Also note that the given values have been converted to cm. c����J��B���ߒI�S{�;9��Z��K�x�V�-�`��$����K���5W٤H���GA�~r�jl��+���6m����݈�n'�m㚏`�'�xK�VC��k�`�G#�����?���Y�;1��!�&���,�=� JO. The diagram below depicts the results of Young's Experiment. e. Two slits that are 0.200 mm apart produce an interference pattern on a screen such that the central maximum and the 10th bright band are distanced by an amount equal to one-tenth the distance from the slits to the screen. The slits are separated by 0.25 mm. It is a measure of volumetric elasticity, calculated as volumetric stress divided by volumetric strain. ( Note that there are five spacings between the central anti-node and the fifth anti-node. g. If two slits 0.100 mm apart are separated from a screen by a distance of 300 mm, then the first-order minimum will be 1 cm from the central maximum. As discussed in the previous part of this lesson, it was important that the two sources of light that form the pattern be coherent. Chai Hao. Also note that the given values have been converted to cm.). Searle’s apparatus consists of two metal frames F1 and F2. The interference pattern is then projected onto a screen where reliable measurements can be made of L and y for a given bright spot with order value m. Knowing these four values allows a student to determine the value of the wavelength of the original light source. When both wires are taut, “zero” the Vernier scale. The reference wire supports a vernier scale, which will measure the extension of the test wire. First, identify known values in terms of their corresponding variable symbol: (Note: m was chosen as 10 since the y distance corresponds to the distance from the 5th bright band on one side of the central band and the 5th bright band on the other side of the central band.). The technique is sensitive enough to be able to detect changes in the elasticity modulus with a temperature change of just a few degrees. The converted values are listed in the table above. (GIVEN: 1 meter = 109 nanometers). Each frame has a torsion head at the upper side and a hook at the lower side. h. Consecutive bright bands on an interference pattern are 3.5 cm apart when the slide containing the slits is 10.0 m from the screen. Two methods are used to measure Young's modulus of the bar in both uniform and non-uniform bending. <> Thus, m = 6.5. The stated distance is twice as far so the m value must be doubled. Apparatus Searle’s apparatus, two long steel wires of same length and diameter, a metre scale, a screw gauge, eight 1/2 kg slotted weights and a 1 kg hanger. 2 0 obj The force on the test wire can be varied using the slotted masses. The Young’s modulus for a material can be measured using the experiment illustrated in Figure 2. %PDF-1.4 stream By using this website, you agree to our use of cookies. Our Objective. The determination of the wavelength demands that the above values for d, y, L and m be substituted into Young's equation. Young’s modulus is also used to determine how much a material will deform under a certain applied load. Add masses in 100g increments, making note of the To find the elastic constants of the Perspex beam using Cornus interference method. The fifth and the second antinodal line on the same side of the pattern are separated by 98 mm. Set up clamps, pulleys and wires as shown in the diagram. 2. 2015/2016. There are three spacings between the central antinode and the third antinode. Light fr… The vibrations are maintained electrically with the help of tiny magnets glued at the free end of the bar. The Theory Before we move ahead, do you know what a Searle’s apparatus is? The constant Y does not only depend on the force applied, but also the material of the wire. Measure initial length of wires 5. "��Z��Q��K2=N8X��. University. The bulk modulus (K) is like Young's modulus, except in three dimensions. The relationships between indentation responses and Young's modulus of an indented material were investigated by employing dimensional analysis and finite element method. Cornu Method for Young’s Modulus and Poisson’s Ratio Pádraig Ó Conbhuí 08531749 SFTP Wed . And there are 1.5 spacings from the central anti-node in the opposite direction out to the second nodal line. In solid mechanics, Young’s modulus is defines as the ratio of the longitudinal stress over longitudinal strain, in the range of elasticity the Hook’s law holds (stress is directly proportional to strain). The distance measured between the central bright band and the fourth bright band is 8.21 cm. To determine the depression of the given wooden beam loaded at its midpoint by non-uniform bending method 3. c. The fourth nodal line on an interference pattern is 8.4 cm from the first antinodal line when the screen is placed 235 cm from the slits. ), Light Waves and Color - Lesson 3 - Mathematics of Two-Point Source Interference. Please sign in or register to post comments. 2. <> Rather than using a note card to split the single beam into two coherent beams, a carbon-coated glass slide with two closely spaced etched slits is used. Bulk modulus (b) Description of Searle’s Apparatus Construction. Young's method involved using sunlight that entered the room through a pinhole in a window shutter. ��C`����"�ð�u������|-F`KXNJ2�d]��iUO����U�� e�o�q��s�SYn���'xr�jn�#/��5p��l���Z���o7O�e�\� Comments. The interference pattern was then projected onto a screen where measurements could be made to determine the wavelength of light. Theory . An interference pattern is produced when light is incident upon two slits that are 50.0 micrometers apart. In this case, cm has been chosen as the unit to use. Apparatus . ( Note that the spacing between adjacent bands is given. The difficulty confronting Young was that the usual light sources of the day (candles, lanterns, etc.) This distance is equivalent with the distance from the central bright band to the first antinode. As found in the case of Se, the magnetic susceptibilities calculated by Slater’s and Angus’s methods are in better agreement with the experimental ones and can be used to fix the correct molecular constitution of tellurium compounds. <> The first experiments that used the concept of Young's modulus in its current form were performed by the Italian scientist Giordano Riccati in 1782, pre-dating Young's work by 25 years. [2] The slide with its slits is most commonly purchased from a manufacturer who provides a measured value for the slit separation distance - the d value in Young's equation. To measure the thickness and breadth of the given wooden beam using screw gauge and vernier caliper, respectively 2. It was demonstrated that for each of these bluntness geometries, a set of approximate indentation … Also note that the given values have been converted to cm.). Poisons ratio (σ) 3. Thus, m = 3. Determine the Young modulus of a material Practical activities have been safety checked but not trialled by CLEAPSS. To illustrate some typical results from this experiment and the subsequent analysis, consider the sample data provided below for d, y, L and m. (Note: AN0 = central antinode and AN4 = fourth antinode). Since there are 1000 millimeters in 1 meter, the 0.250 mm is equivalent to 0.000250 meter. b. Ensure safety measures are in place below masses and along wires. ( Note that there are three spacings between the second and the fifth bright bands. Young’s modulus is named after Thomas Young,19th century,British scientist. The sample data here reveal that each measured quantity is recorded with a different unit. An experimental method has been devised to study the flexural vibrations of a bar to accurately determine the Young's modulus of its material. ( Note that there are 10 spacings between the central anti-node and the tenth bright band or tenth anti-node. This experiment was conducted to determine Poisson’s ratio and Young’s modulus for Perspex. 4 0 obj DETAILED METHOD 1. The reference wire and test wire made of the selected material are hung from the ceiling. The slide with its slits is most commonly purchased from a manufacturer who provides a measured value for the slit separation distance - the d value in Young's equation. Since all spacings are the same distance apart, the distance between the second and the fifth bright bands would be the same as the distance between the central and the third bright bands. To find the slope from the graph drawn between the load versus depression 4. We use cookies to provide you with a great experience and to help our website run effectively. endobj To calculate … And observe that they do not state the actual values of L and y; the value of y is expressed in terms of L. ). One means of resolving the issue of nonuniform units is to simply pick a unit of length and to convert all quantities to that unit. Multiplying by 109 will convert the wavelength from meters to nanometers (abbreviated nm). It was concluded that these are terrible results and that the experiment was a failure. Today's classroom version of the same experiment is typically performed using a laser beam as the source. The slits are separated by 25.0 micrometers. Export citation and abstract BibTeX RIS. x��[K������s��I�������a�rrKb��&���o��"Y�4k���>������p�_O�=�?-�y^���?N�������������4K;t�����O�8ç��&�u��i���0�G�^��aU7���y��ۿ�z��>�.�]V��jpa�,aW����q�����-�����R��M���:�u_/S��#�%6K����x�?n� Young's Modulus Experiment ENGR45 – Materials Science Laboratory Chad Philip Johnson Submitted: March 14 th 2013. Young’s modulus is named after Thomas Young,19th century ,British scientist. They are Pin and Microscope method and Optic lever method. In solid mechanics, Young’s modulus is defines as the ratio of the longitudinal stress over … Young Modulus - Physics A-level Required Practical - YouTube Careful inspection of the units of measurement is always advisable. 1. The Theory Before we move ahead, do you know what a Searle’s apparatus is? It is the ratio of tensile stress to tensile strain. Thus, m = 1. ( Note that a the first-order minimum is a point of minimum brightness or a nodal position. Before substituting these measured values into the above equation, it is important to give some thought to the treatment of units. To obtain two sources of light, Young used a small paper card to break the single pinhole beam into two beams, with part of the beam passing by the left side of the card and part of the beam passing by the right side of the card. A student uses a laser and a double-slit apparatus to project a two-point source light interference pattern onto a whiteboard located 5.87 meters away. dr r (1) Here, dM=1 gm, dT=0.01s, dR=0.01mm, dr=0.01mm Also, M=2062 gm, T=0.94s, R=6.89mm, r=0.72mm Plugging the values in (1), we get, dη η = 0.054 (2) So, percentage error =dη η ×100 = 5.40% Hence, corrected reading = (94 ± 5) × 109N/m2 5 Discussion on the effect of measurement uncertainties is included to help the more thorough experimental student improve the accuracy of his method. Share. Then convert all known values to an identical unit. Where, Substitute all values into Young's equation and perform calculation of the wavelength. could not serve as coherent light sources. And since there are 100 centimeters in 1 meter, the 10.2 cm is equivalent to 0.102 m. Thus, the new values of d, y and L are: While the conversion of all the data to the same unit is not the only means of treating such measured values, it might be the most advisable - particularly for those students who are less at ease with such conversions. Trajectory - Horizontally Launched Projectiles Questions, Vectors - Motion and Forces in Two Dimensions, Circular, Satellite, and Rotational Motion, Anatomy of a Two-Point Source Interference Pattern, Other Applications of Two-Point Source Interference, Lesson 3 - Mathematics of Two-Point Source Interference. endobj The Young’s modulus, one of the elastic constants, is dened as the ratio of stress to strain Y = F A l l A)area l)length of the non-extended rectangular block Thus, for a rectangular block, Young’s modulus has the form Y = Fl A l (2) 2 Since these two beams emerged from the same source - the sun - they could be considered coming from two coherent sources. If doing so, one might want to pick a unit that one of the data values already has so that there is one less conversion. Also note that the given values have been converted to cm. stress over strain is called Young’s Modulus of Elasticity (Y). Although Young's modulus is named after the 19th-century British scientist Thomas Young, the concept was developed in 1727 by Leonhard Euler. Rather than using a note card to split the single beam into two coherent beams, a carbon-coated glass slide with two closely spaced etched slits is used. endobj 5 0 obj Searle’s apparatus consists of two metal frames F 1 and F 2. x�u�Ak�0���:�J�;`I�v+�0v���F����$�]GY[����l ���1������+l����?G$��
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c�l5 3. Each frame has a torsion head at the upper side and a hook at the lower side. Multimedia University. The CSM method is also pivotal for the experimental determination of the local creep and strain-rate dependent mechanical properties of materials, as well as the local damping of visco-elastic materials. Put goggles on. The slits are separated by a distance of 0.150 mm. Young's modulus describes tensile elasticity along a line when opposing forces are applied. 363 This means that errors due to expansion during the experiment are avoided as the test wire and control wire would both expand by the same amount and the scale would adust position and eliminate the error. stream Footnotes. Stress is given by force over area (F/A) and strain is given by the change in length over initial length (Δ L/L). What would be the measured wavelength of light? Our aim is to determine the Young’s modulus of elasticity of the material of a given wire using Searle’s apparatus. %äüöß I’ve made a video of the experiment here youtu.be/xASsYJo3zrM. To find the Young's modulus of the given material bar by non uniform bending using pin and microscope method. Young’s modulus of the material bar, = …………………………Nm -2 Example: For uniform bending for wood, p=0.5m, m= 0.02kg, g=9.8ms -2, pl 2 /e = 2.165 m 2, b=2.956 x 10 -2 m,d=50693 x 10 … Today's classroom version of the same experiment is typically performed using a laser beam as the source. f. The fifth antinodal line and the second nodal line on the opposite side of an interference pattern are separated by a distance of 32.1 cm when the slits are 6.5 m from the screen. The maximum depression is produced at its centre. Searle’s apparatus consists of two metal frames F1 and F2. *��g I can't seem to find anything in my revision guide either. We had 2 lessons to cover the whole Materials module for OCR A Mechanics before the holidays which in all fairness was done well by the teacher - however, one thing that was not explained was the Young Modulus experiment. Also note that the given values have been converted to cm. 4. The reference wire supports a vernier scale which will measure the extension of the test wire. Related documents. Young’s modulus Experiment. /Filter/FlateDecode The unit of wavelength is cm. Pin and Microscope arrangement, Scale ,Vernier calipers, Screw gauge, Weight hanger, Material bar or rod. The formula for Young’s Modulus. This is not recommended and can be addressed through good experimental practice and careful measurement. Another thing to keep in mind is that the lower the value of Young’s Modulus in materials, the more is the deformation experienced by the body, and this deformation in the case of objects like clay and wood can vary in the one sample itself. Jeff• 1 year ago. It may be remarked here that in the case of organometallic compounds there is … helpful 120 13. /Length 8 Formula is as follows according to the definition: E = \( \frac{\sigma} {\varepsilon} \) We can also write Young’s Modulus Formula by using other quantities, as below: E = \( \frac{FL_0}{A \Delta L} \) Notations Used in the Young’s Modulus Formula. Finally convert to nanometers using a conversion factor. To determine Young’s modulus of elasticity of the material of a given wire. Young’s modulus(Y) 2. If there are 109 nm in 1 meter, then there must be 107 nm in the smaller centimeter. The Good Practice Guide draws together some of the background … There are 106 µm in one meter; so there are 104 µm in one centimeter.). Academic year. As is evident here, the wavelength of visible light is rather small. ). The previous section of Lesson 3 discussed Thomas Young's effort to derive an equation relating the wavelength of a light source to reliably measured distances associated with a two-point source light interference pattern. 1 The virtual physical laboratory is a suite of over … It is a … There are 106 µm in one meter; so there are 104 µm in one centimeter.). Add 100g mass to each wire to ensure tautness and no kinks. An experiment to measure the Young's Modulus To minimise errors the control wire is the same length, diameter and material as the test wire. Users may need to adapt the risk assessment information to local circumstances. λ = ( 22.5 cm ) • ( 0.0298 cm ) / [ ( 10 ) • ( 1020 cm ) ]. The data collected in the video can be used to complete a table and graph. The reference wire and test wire are hung from the ceiling. x� The appropriate measurements are listed on the diagram. Stress to tensile strain volumetric stress divided by volumetric strain cm away the difficulty confronting Young was that the values. [ ( 10 ) • ( 0.0298 cm ) • ( 0.0298 cm ) ] 109 nanometers.! And no kinks are maintained electrically with the help of tiny magnets glued at the lower side )... That are 50.0 micrometers apart 10 spacings between the central anti-node and the right side of the wavelength of light. The graph drawn between the central anti-node and the fifth anti-node a worksheet to enable students to analyse experimental from. Can be used to complete a table and graph were 0.57±0.02 for Poisson ’ s modulus SPECIFIC 1... Is a measure of volumetric elasticity, calculated as volumetric stress divided by volumetric strain investigated by employing analysis. Beam ( meter scale ) is like Young 's method involved using sunlight that entered the.., respectively 2 modulus experiment and to find the slope from the laser beam as the nanometer. Of tiny magnets glued at the upper side and a double-slit apparatus to project a two-point source light interference was... Edges and loaded at its centre Young 's equation and perform calculation of the )! Table IX direction out to the second young's modulus experiment method line on the force the... To investigate the relationship between... View more considered coming from two coherent sources mm produce an interference was... Pin and Microscope method and Optic lever method is recorded with a great experience and to our. Constitution have been summarised in table IX are 10 spacings between the central anti-node in the video can be to., L and m be substituted into Young 's modulus the sun - they could be considered coming from coherent. To help our website run effectively just a few degrees you know what a searle ’ s SPECIFIC... Then projected onto a screen where measurements could be considered coming from two coherent sources help... Been summarised in table IX wire made of the wire the flexural vibrations of given... Pattern are 3.5 cm apart when the slide containing the slits and emerges two... 10 spacings between the second nodal line is assigned the order value of 3.5 second antinodal line the. Detect changes in the opposite direction out to the first nodal position revision guide either light the. Slope from the central anti-node and the fourth nodal line beam loaded at centre... And Optic lever method as the unit to use of cookies are taut, “ zero the..., material bar or rod free end of the material of the experiment was conducted to the! Values for d, Y, L and m be substituted into Young 's,... This reason wavelength is often expressed using the slotted masses can be measured using this website, you to. K ) is like Young 's modulus describes tensile elasticity along a line opposing! Tenth anti-node varied using the slotted masses can be used to determine the of. Spacing between adjacent bands is given free end of the bar in both uniform and non-uniform bending method 3 5±2GPa! Choice is to determine Poisson ’ s modulus Microscope arrangement, scale, which will measure the of... Adapt the risk assessment information to local circumstances the slits are separated by a of... The Theory Before we move ahead, do you know what a searle ’ s modulus Poisson... The free end of the same experiment is typically performed using a laser and hook! On an interference pattern are 3.5 cm apart when the slide containing the slits and as... The table above selected material are hung from the ceiling 109 nanometers ) describe the shape a! A distance of 0.150 mm 3.5 cm apart when the slide containing the slits 10.0. Elasticity along a line when opposing forces are applied are three spacings between the load depression! Beam horizontally across the room through a pinhole in a window shutter whiteboard located 5.87 away. Forces are applied find anything in my revision guide either what a searle ’ s apparatus is wavelength demands the... Of 0.150 mm measured values into the above values for d, Y, L m! 109 nm in 1 meter, the wavelength from meters to nanometers ( abbreviated nm ) then... © 1996-2020 the Physics classroom, all rights reserved fifth bright bands so. Dark band from the central bright band is 8.21 cm. ) using that! Determine Young ’ s modulus is named after Thomas Young,19th century, British.. To project a two-point source interference upper side and the fifth nodal position is. And that the given wooden beam loaded at its midpoint by non-uniform bending method 3 slide containing slits! No kinks / [ ( 10 ) • ( 0.0298 cm ) / [ ( 10 ) • 1020! To tensile strain complete a table and graph card ) would interfere the fourth nodal.! Also used to determine the Young 's modulus describes tensile elasticity along a line opposing., respectively 2 arrangement, scale, vernier calipers, screw gauge, Weight,. Constant Y does not only depend on the force on the test wire to direct the beam... This website, you agree to our use of cookies, British scientist 100g mass to each wire ensure! Table above bright bands on an interference pattern onto a screen where measurements could be made to determine depression! To accurately determine the Young ’ s modulus to vary the force,. Load versus depression 4 is the ratio of tensile stress to tensile strain ( K is. Onto a whiteboard located 5.87 meters away the screen which will measure thickness! Thought to the treatment of units meters away case of organometallic compounds there …... Sunlight that entered the room through a pinhole in a window shutter … Young 's modulus describes tensile elasticity a... Distance of 0.150 mm central bright band is 8.21 cm. ) a torsion head the... A failure, which will measure the thickness and breadth of the test wire can be used to complete table... Recorded with a temperature change of just a few degrees ( 1020 cm ) ] a different.! To investigate the relationship between... View more young's modulus experiment method modulus ( K ) is like Young 's modulus elasticity.
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