Compact Thermal Expansion Apparatus Manual TD 8578

Instruction Manual andExperiment Guide for the PASCO scientific Model TD-8578 THERMAL EXPANSION APPARATUS © 1999 PASCO scientific 012-07114D .......... 2 EXPERIMENT: Measuring the Coefficient of Linear Expansion for Copper..................................... 7 i ............................... Brass..............................012-07114D Thermal Expansion Apparatus Table of Contents Section Page Copyright............................................................................ 4 Questions ........................................................................................... ii INTRODUCTION: Equipment........................................................................................................................ 3 Procedure .... 1 Notes on Temperature Measurement ............... 2 Changing Tubes ............................................................................................. 5 Technical Support ...................................................................................... 2 Replacement Parts ......................................................... and Aluminum: Introduction ................ 1 Additional Equipment Required ... 5 Thermistor Conversion Table: ............................................................................................................................................................................................. 3 Data and Calculations ........................................................ 1 Accepted Values for Coefficient of Thermal Expansion ...................................................... Warranty and Equipment Return ...... pasco. Roseville. Reproduction under any other circumstances. phone. ➁ Make certain there are at least two inches of packing material between any point on the apparatus and the inside walls of the carton. observe the following rules: PASCO scientific warrants the product to be free from defects in materials and workmanship for a period of one year from the date of shipment to the customer. Carriers will not accept responsibility for damage caused by improper packing. the units must be packed properly. permission is granted to non-profit educational institutions for reproduction of any part of the manual providing the reproductions are used only for their laboratories and are not sold for profit. Determination of whether a product failure is the result of a manufacturing defect or improper use by the customer shall be made solely by PASCO scientific.com . To be certain the unit will not be damaged in shipment. ➤ NOTE: NO EQUIPMENT WILL BE ACCEPTED FOR RETURN WITHOUT AN AUTHORIZATION FROM PASCO.com www. Should the product have to be returned to PASCO scientific for any reason. is prohibited. notify PASCO scientific by letter. the return authorization and shipping instructions will be promptly issued. ➀ The packing carton must be strong enough for the item shipped. Equipment must be properly packed to prevent damage and shipped postage or freight prepaid. Warranty and Equipment Return Please—Feel free to duplicate this manual subject to the copyright restrictions below.) Shipping costs for returning the equipment after repair will be paid by PASCO scientific. (Damage caused by improper packing of the equipment for return shipment will not be covered by the warranty. However. Upon notification. CA 95747-7100 Phone: FAX: email: web: (916) 786-3800 (916) 786-3292 techsupp@pasco. Copyright Notice Equipment Return The PASCO scientific 012-07114 Thermal Expansion manual is copyrighted and all rights reserved.Thermal Expansion Apparatus 012-07114D Copyright. without the written consent of PASCO scientific. or fax BEFORE returning the product. Limited Warranty When returning equipment for repair. allowing the instrument come in contact with the packing carton. ii Address: PASCO scientific 10101 Foothills Blvd. Responsibility for the return of equipment for warranty repair belongs to the customer. PASCO will repair or replace at its option any part of the product which is deemed to be defective in material or workmanship. The warranty does not cover damage to the product caused by abuse or improper use. ➂ Make certain that the packing material cannot shift in the box or become compressed. The expansion of the metal is measured with 0. copper. In addition to the TD-8578 Thermal Expansion Apparatus. ➤ ➤NOTE: The dial gauge can be removed or repositioned by loosening the set screw on the dial gauge mounting block.9% Al. or aluminum tube is placed on the expansion base. 0. If you wish to investigate the expansion of the metals at additional temperatures.D. The foam insulator is used to inhibit heat loss through the thermistor lug so the lug temperature closely follows the tube temperature. Notes on Temperature Measurement A thermistor's resistance varies reliably with temperature. the following items are needed to perform the experiment: ➀ A source of steam or hot water. such as PASCO Model SE-9750 or SE-9751 Patch Cords. then steam is passed through it. 1 .4 mm I. the brass. The length of the tube is measured at room temperature. • Three metal tubes — brass. Temperatures are measured to within 0.01 mm resolution using the built-in dial-gauge. and aluminum (98. The thermistor used to measure the tube temperature is embedded in the thermistor lug. and converted to a temperature measurement using the attached conversion table tag and also on the back page of this manual. Leads should have banana plug connectors. • Thermoplastic elastometer tubing with 6.2 °C. Complete step by step instructions and a data sheet for results are provided on the following pages. • A foam insulator to avoid heat loss at the thermistor connection point.2 °C using a thermistor attached to the center of the tube. The insulator does not have any appreciable effect on the local temperature of the tube itself. ➃ If additional data points are desired you will also need: a source of hot or cold water. copper (99. Although the relationship between temperature and resistance is not linear. 0. Once thermal equilibrium has been reached. such as the PASCO Model TD-8556A Steam Generator. copper.4% Si): 6.4 mm outside diameter. and aluminum.7% Mg. 0. a linear approximation can be accurately used to interpolate between table data points with an accuracy of approximately ±0. ➂ A container to catch the water as it drains out of the tube. the heat is highly uniform along the length of the tube.012-07114D Thermal Expansion Apparatus Introduction Introduction Additional Equipment Required The PASCO Model TD-8578 Thermal Expansion Apparatus provides easy and accurate measurements of the coefficient of linear expansion for brass. ➁ A digital ohmmeter such as PASCO Model SE9589 to measure the thermistor resistance.5% Te). To make the measurement. Equipment Your TD-8578 Thermal Expansion Apparatus includes: • A 40 cm long expansion base with a built-in dial gauge and thermistor. hot or cold water can be passed through the tubes. The resistance can be measured with an ohmmeter.5% Cu. thermistor capture spring thermal rod 2 PASCO # Mod. be careful not to pull the wires off of the thermistor. ➂ Release spring. Thermistor (100k V) 150-031 AL Tube 648-07139 Cu Tube 648-07141 Brass Tube 648-07140 Foam Insulator 716-041 Dial Gauge 620-050 . ➁ Insert the curved lug of the thermistor between the capture spring and the thermal tube. ➀ Compress the capture spring by pressing the two ends together.Thermal Expansion Apparatus 012-07114D Replacement Parts Accepted Values for Coefficient of Thermal Expansion Material a ( x10-6/ 8C) Copper 17 Brass 19 Aluminum 23 The following parts can be ordered from PASCO scientific. Item Changing Tubes ➤ Caution: When changing tubes. Materials that are not isotropic. Procedure ➀ Measure L. Therefore. but on the absolute temperature as well. If ∆T is reasonably small. which increases the average separation between the atoms. and Aluminum Introduction Most materials expand when heated through a temperature range that does not produce a change in phase. within the limits of this experiment. The added heat increases the average amplitude of vibration of the atoms in the material.012-07114D Thermal Expansion Apparatus Experiment: Measuring the Coefficient of Linear Expansion for Copper. such as an asymmetric crystal for example. Stated mathematically: ∆L = αL ∆T. The lug will be aligned with the axis of the tube. you will measure α for copper. α can also vary somewhat with temperature. Measure from the outer edge of the stainless steel ring on one end. ➁ Mount the copper tube in the expansion base as shown in Figure 2. Suppose an object of length L undergoes a temperature change of magnitude ∆T. so it is necessary to measure α along only one dimension. In this experiment. and brass. Brass. the change in length. Also. to the outer edge of the stainless steel ring at the other end (see Figure 1). The stainless steel ring on the tube fits into the slot on the slotted mounting block and the bracket on the tube presses against the spring arm of the dial gauge. so there is maximum contact between the lug and the tube. as shown in Figure 2. the degree of expansion depends not only on the magnitude of the temperature change. α can have a different value depending on the axis along which the expansion is measured. aluminum. These metals are isotropic. ➂ Use the capture spring on the expansion tube to attach the thermistor lug somewhere in the middle of the copper tube. the length of the copper tube at room temperature. ∆L. is generally proportional to L and ∆T. L Figure 1 Measuring Tube Length stainless steel ring stainless steel ring capture spring thermistor slotted mounting block contact indicator Figure 2 Equipment Setup (Top View) 3 . where α is called the coefficient of linear expansion for the material. Record your results in Table 1. α does not vary with temperature. As the tube expands. ➇ Place a container under the other end of the tube to catch the draining water.01 mm of tube expansion. you must interpolate between the temperature values listed in the Thermistor Conversion Table. Attach it to the end closest to the dial gauge. the resistance of the thermistor at room temperature. ➆ Use tubing to attach your steam generator to the end of the copper tube. The banana plug connectors are located at one end of this unit in a stop bracket.Thermal Expansion Apparatus 012-07114D ➃ Place the foam insulator over the thermistor lug. record the resistance (Rhot) in Table 1. Record this value in the table. ➤Note: To achieve 0. ➅ Measure and record Rrm. (Each increment on the dial gauge is equivalent to 0. ➄ Plug the leads of your ohmmeter into the banana plug connectors labeled THERMISTOR in the center of the expansion base. 4 D T ( 8C) . Record your results in the table. Trm and Thot. When the thermistor resistance stabilizes.) ➤Repeat the experiment for the brass and aluminum tubes. watch the dial gauge and the ohmmeter. Also record the expansion of the tube length (∆L) as indicated by the displacement of the indicator on the dial gauge. ➈ Turn the outer casing of the dial gauge to align the zero point on the scale with the long indicator needle.2°C accuracy for temperature. Convert your thermistor resistance measurements. Rrm and Rhot. As steam begins to flow. into temperature measurements. the indicator needle will move in a counterclockwise direction. ➉ Turn on the steam generator. Data and Calculations TABLE 1 Data and Calculations CALCULATIONS DATA L(mm) R rm ( V ) R D L(mm) hot (V ) T rm ( 8C) T hot ( 8C) copper brass aluminum ➀ Use the Thermistor Conversion Table on page 5 of this manual or on the tag attached to the apparatus. 905 46.591 32.467 10.707.223 10. (Ω) 351. speculate on the possible sources of error in your experiment. Record the result in the table.837 10.480 60.569.022 83.969.138 55.437.610 133.292 39.625 11.410 13. (°C) 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 5 Res.743 58. brass.356 63.580 139.000 126.810 115.736 20.260 218.3 Temp.850 104.8 6.990 283.816.012-07114D Thermal Expansion Apparatus ➁ Calculate ∆T = Thot – Trm.386 18. (Ω) 95.330.475 26.321 16.689 16.600 269. αCu = __________________ αBrass = __________________ αAl = __________________ Questions ➀ Look up the accepted values for the linear expansion coefficient for copper.991 33.136 19.903 72.000 Temp.297 51. ➂ Using the equation ∆L = αL ∆T.932 12.917 43.0 6.4 6.730 207.755.190 109.995 36.380 66.840 178.7 8. (°C) 30. (Ω) 11.320 298.522.8 8.240.8 5.863 44.767.730 153.590 21.020 332.120.640 315.980.390 24.380 242.422 75.1 5.539.1 7.560 187.605 37. and aluminum. calculate α for copper.749.0 8.668 17.7 7.897 13. steel.945 14.502 14.080 255.043 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 Res.214.9 6.756 28.415 23.456.124 79. What is the percentage difference in each case? Is your experimental error consistently high or low? ➁ On the basis of your answers in question 1.253 Temp.740 120.479 12.405 12.483 22. Compare these values with your experimental values.126 87.7 9.062 41.590 27. (°C) 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 .560 69.950 161.6 6.919 20.658 53.6 7. (°C) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Res.850 197.2 9.409 25.3 5.458 34.2 7. (Ω) Temp. How might you improve the accuracy of the experiment? THERMISTOR CONVERSION TABLE: Temperature versus Resistance Res.800 100.980 17.976 29.129.083 15.110 9.950 146.650 169.048 48. and aluminum.447 91.460 230.936. Thermal Expansion Apparatus 012-07114D Notes 6 . Before you call the PASCO Technical Support staff.pasco. To Reach PASCO . ➤ If your problem relates to the instruction manual. you won’t lose valuable data).S. Your input helps us evaluate and improve our product. have the apparatus within reach when calling to facilitate description of individual parts.com web: www. (916) 786-3292 e-mail: techsupp@pasco. please let us know. 7 . note: . note: .A detailed description of the problem/sequence of For technical support.Approximate age of apparatus. it would be helpful to prepare the following information: ➤ If your problem is with the PASCO apparatus.If possible. If you have any suggestions on alternate experiments or find a problem in the manual. . fax: events (in case you can’t call PASCO right away.Title and model number (usually listed on the label). please tell us.Part number and revision (listed by month and year on the front cover).) or (916) 786-3800. .com . call us at 1-800-772-8700 (toll-free within the U.012-07114D Thermal Expansion Apparatus Technical Support Feedback Contacting Technical Support If you have any comments about the product or manual.Have the manual at hand to discuss your questions. PASCO appreciates any customer feedback.