Building an Electric Heater

Transcription

1 Science, Technlgy, Engineering and Math Objectives: Students will research science tpics including: Heat and temperature change Wire resistance Electrical heating pwer Heating and cling rate Students will engineer and build a simple electric heater that will warm an bject). Students will use apprpriate technlgy t evaluate their design, cllabrate with clleagues and present their findings. Students will use a simulatin t understand and mdel the effects f wire type, crss sectin and length n heating pwer. Students will use mathematical prcesses f: Graphing Linear equatin mdeling Regressin analysis Data analysis Vcabulary Resistivity Heating pwer Current Heating/cling rate Vltage Abut the Lessn While using TI-Nspire technlgy, this prject based STEM activity will engage yur students in the engineering design prcess: Identify Research Design Create Evaluate Cmmunicate Tech Tips: This activity includes screen captures taken frm the TI- Nspire App fr ipad. It culd als be used with the TI- Nspire family f prducts including TI-Nspire handheld and sftware and a traditinal wired Vernier temperature sensr. Slight variatins t these directins may be required if using ther technlgies besides the ipad app. Watch fr additinal Tech Tips thrughut the activity fr the specific technlgy yu are using. Access free tutrials at latrs/pd/us/online- Learning/Tutrials Lessn Files: Student Activity Build_an_Electric_Heater_S tudent.dc Build_an_Electric_Heater_S tudent.pdf Build_an_Electric_Heater.tn s 2015 Texas Instruments Incrprated 1 educatin.ti.cm

2 Activity Materials Per Student Grup Cmpatible TI Technlgies: TI-Nspire Apps fr ipad Vernier G Wireless Temp sensr Drinking straw withut paper jacket 2 meters f Magnet Wire 24 Gauge AWG Enameled Cpper 6-Vlt Super Heavy Duty Lantern Battery Knife Blade switch-single ple single thrw (duble thrw if ptinal fan is used) Insulated alligatr clip leads. 5vlt brushless DC cling fan 25mm x 25mm Safety Tip: Make sure yur students remve the paper wrapper frm the drinking straw. Safety Tip: D nt leave battery attached after experiment as heater may becme t ht. Safety Tip: Never use an electrical receptacle as a pwer surce in this activity. Discussin Pints and Pssible Answers The Engineering Prblem Yur Cmpany designs and manufactures cnsumer electrnics. Yur prject manager has tasked yu with designing a new line f battery pwered cnsumer appliances that will keep a ht drink, such as cffee r tea, warm fr a lng perid f time. Yur task is t design a small electric heating element fr the new line f prducts and t verify yur design with test data. STEM Career An electrical engineer is a persn wh generally deals with the study and applicatin f electricity, electrnics and electrmagnetism. It is a branch f engineering that may invlve the design, prductin and the peratin f pwer utilities, autmtive and cnsumer electrnics Texas Instruments Incrprated 2 educatin.ti.cm

3 Teacher Tip: Students may find it valuable t serve specific rles while they wrk in grups t cmplete these prjects. Career Rles Sme pssible rles culd include Prject Manager This persn ensures that all members f the team are meeting their deliverables. The prject manager is the creatr and manager f the schedule and ensures tasks are being cmpleted n time. Safety Facilitatr This rle ensures the area is clean and safe fr the prductin f the prject. Fr this specific prject, this persn may wish t actively bserve that the materials are able t withstand heat being generated. They will need t keep a watchful eye ver the electric heater and the data that is generated. Engineer This individual is cmfrtable with making recmmendatins n the design f the prject. They have researched the materials, supplies, and underlying mechanisms fr the suggested design. They will create the design, likely digitally r n paper, befre it is tested. Builder The builder will actually fllw the design f the prject and put all f the pieces tgether. The builder will als discuss with the engineer and safety facilitatr any changes necessary fr the design. 1. Identify: State yur engineering gal here. What are yu trying t build? What des it need t accmplish? Hw will yu evaluate hw well it wrks? 2. Research: Use apprpriate internet resurces t learn abut yur engineering gal. Yur research may include building prcesses, cnstraints, ptential prblems, surces f errr, materials, time limits, and scientific principles that apply t yur design. Make sure yu pay clse attentin t the Backgrund Infrmatin and the instructins that are included n page 1.3. Use this infrmatin as yu experiment with the simulatin n page 1.4 in the dcument. Pay attentin t the warning messages that may pp up during the simulatin. Check yur understanding by answering the questins that fllw the simulatin in the dcument Texas Instruments Incrprated 3 educatin.ti.cm

4 Teacher Tip: Page 1.11 in the dcument explains the equatin fr resistance t the students. Students are challenged with trying t slve a prblem with knwn variables. Use the equatin: r = (ρ l)/a where, r = resistance (Ω); value is unknwn ρ = material resistivity (Ω/m); Ω/m l = length f wire (m); 200 cc r 2 m d = diameter f wire (m); cc r m Use diameter t determine Crss Sectinal Area (A) with the area f a circle frmula, A = πr 2. π ( m/2) 2 = m 2 A = crss sectinal area (m 2 ); m 2 r = Ω/m 2m m 2 r = Ω 3. Design/Prttype: Once yu have researched the engineering gal, create a plan fr the building f yur design. Yur design may include drawings, labels, materials lists, cst lists, etc. The prttype may be a first-time attempt at building the final prduct t learn hw t put it tgether. Share yur design and prttype with thers, listen t their suggestins and decide fr yurself the very best design. a) Increasing the crss sectinal area f a piece f wire will Answer: B. decrease the resistance b) Increasing the resistivity f a piece f wire will Answer: A. increase the resistance c) What is the best cmbinatin fr building an electric heater Answer: A. Lng thin nichrme wire d) A battery can t deliver much current. T reduce the current flw an engineer culd Answer: C Bth A and B wuld wrk e) T increase current flw thrugh the circuit, an engineer culd Answer: D All f the abve 2015 Texas Instruments Incrprated 4 educatin.ti.cm

5 4. Create/Build: Use yur design and prttype experience t build yur prduct t yur specificatins. 5. Evaluate/Test: Design an experiment that will help yu t decide the best design t accmplish the engineering gal. Yu can use the Vernier G Wireless Temp prbe. On page 3.2 yu will find data cllectin page fr the Temp prbe. 6. Analyze: Determine a methd t analyze the cllected temperature data that will help yu t decide the best design. Yu might cnsider: change in temperature, best-fit linear regressin, and expnential decay mdels 7. Refine: After yu have built yur design and tested it, think abut what yu like and d nt like abut the design. Shw yur prduct t yur friends and family and listen carefully t their cmments. Include the best suggestins frm yur custmer feedback int yur design and rebuild yur deign t make it better! Observatins students shuld make during their experiment(s) a) Describe the shape f yur graph. Answer: Mst students will likely see a graph that starts with a high slpe but subtly decreases int a lwer slpe. b) What was yur starting temperature? c) What was yur final temperature? d) As the slpe f the graph changed, describe what was happening. Answer: The bigger the difference in temperature, the higher the rate f change f the graph. As the heat f the thermmeter appraches the heat f the heater, the rate f change will decrease prprtinally Texas Instruments Incrprated 5 educatin.ti.cm

6 Pssible results frm prject evaluatin. The data shwn was frm a straw with 80 turns and was allwed t heat fr 4 minutes, 30 secnds. (dne with Vernier DataQuest with a Vernier EasyTemp sensr and TI-Nspire CX Handheld) 8. Present: Prepare a brief presentatin f yur creatin in a clud-based cllabrative envirnment such as Ggle Drive. Share yur presentatin with yur teacher, family and friends. Wrap-Up Students will have the pprtunities t try a different number f lps with the wire t see hw length will influence resistance and heat prductin. Assessment Students will answer questins t ensure they understand the relatinships between crss sectinal area, wire length, resistivity, and current flw in a cnductr Texas Instruments Incrprated 6 educatin.ti.cm