The steps of the engineering design process are to:

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2 The engineering design prcess is a series f steps that engineers fllw t cme up with a slutin t a prblem. Many times the slutin invlves designing a prduct (like a machine r cmputer cde) that meets certain criteria and/r accmplishes a certain task. The steps f the engineering design prcess are t: Define the Prblem D Backgrund Research Specify Requirements Brainstrm Slutins Chse the Best Slutin D Develpment Wrk Build a Prttype Test and Redesign Engineers d nt always fllw the engineering design prcess steps in rder, ne after anther. It is very cmmn t design smething, test it, find a prblem, and then g back t an earlier step t make a mdificatin r change t yur design. This way f wrking is called iteratin, and it is likely that yur prcess will d the same!

3 Define the Prblem: The engineering design prcess starts when yu ask the fllwing questins abut prblems that yu bserve: D Backgrund Research: Learn frm the experiences f thers this can help yu find ut abut existing slutins t similar prblems, and avid mistakes that were made in the past. S, fr an engineering design prject, d backgrund research in tw majr areas: Specify Requirements: Design requirements state the imprtant characteristics that yur slutin must meet t succeed. One f the best ways t identify the design requirements fr yur slutin is t analyze the cncrete example f a similar, existing prduct, nting each f its key features. Brainstrm Slutins: There are always many gd pssibilities fr slving design prblems. If yu fcus n just ne befre lking at the alternatives, it is almst certain that yu are verlking a better slutin. Gd designers try t generate as many pssible slutins as they can. Chse the Best Slutin: Lk at whether each pssible slutin meets yur design requirements. Sme slutins prbably meet mre requirements than thers. Reject slutins that d nt meet the requirements. Develp the Slutin: Develpment invlves the refinement and imprvement f a slutin, and it cntinues thrughut the design prcess, ften even after a prduct ships t custmers. Build a Prttype: A prttype is an perating versin f a slutin. Often it is made with different materials than the final versin, and generally it is nt as plished. Prttypes are a key step in the develpment f a final slutin, allwing the designer t test hw the slutin will wrk. Test and Redesign: The design prcess invlves multiple iteratins and redesigns f yur final slutin. Yu will likely test yur slutin, find new prblems, make changes, and test new slutins befre settling n a final design. Cmmunicate Results: T cmplete yur prject, cmmunicate yur results t thers in a final reprt and/r a display bard. Prfessinal engineers always d the same, thrughly dcumenting their slutins s that they can be manufactured and supprted. * Adapted frm Science Buddies ( T dwnlad a cpy f this handut and many ther exercises, g t and click n the MOSAC2 links

4 Careening Caster Challenge In this experiment, yu will be challenging yur students t cnstruct the fastest rller caster in class with ne lp r spiral, ne hill at least 5 cm high at the peak, and a degree turn ut f a handful f simple materials. Materials: 6 feet f tubing 3 binding clips 2 paper clips One BB One ring stand Timer/stpwatch 2 sheets f cpy paper Prcedure: 1) Chse which path is best fr yur students t cmplete this challenge. It wuld be best t have them design a slutin first and t explain this design t the grup/class befre running the experiment. Fr advanced students, restrict the testing f their rllercaster until all student grups have cllabrated, built, and drawn their design. 2) Regardless f hw yu apprach this prblem, all times cllected frm these experiments shuld be published fr the class t bserve alng with the design ideas. 3) After cmmunicating results, allw the students t chse the best design and rerun their experiment. 4) Rules fr the students: Rller casters must be attached t the ring stand Caster must be self-starting (n initial pushing) 5) Have the students draw their best design t scale and include the fllwing infrmatin: Height f each hill (including the start and end pints) Maximum ptential energy (PE) Maximum kinetic energy (KE) Areas f decreasing ptential energy and increasing kinetic energy Diameter f the lp r spiral 6) Instruct the students t calculate the mass f the BB, the ptential energy f the BB at the tw highest pints n the caster, its average run time after fur trials, and the average velcity (speed) f the BB. The fllwing wrksheet may assist yu. T dwnlad a cpy f this handut and many ther exercises, g t and click n the MOSAC2 links

5 Names: Date: Careening Caster Student Wrksheet Draw yur rller caster t scale n a sheet f graph paper. Be certain t indicate yur scale in the lwer crner f the drawing. When yu are finished it shuld have the fllwing labels: Height f each hill (including the start and end pints) Maximum ptential energy (PE) Maximum kinetic energy (KE) Areas f decreasing ptential energy and increasing kinetic energy Diameter f the lp r spiral What is the mass f the BB? Calculate the PE at the tw highest pints f the PE in the caster. Remember: gravity=9.8 m/s 2 After fur trials, what was yur average time? 1 st run 2 nd run 3 rd run 4 th run Average run time Calculate the average velcity (speed) f the ball. Be certain t include units.

6 Reverse Engineering Challenge Water t Juice and Back Again In this experiment, yu will demnstrate a specific series f chemical reactins in frnt f yur students and will ask them t recreate yur perfrmance. Materials: 2-3 gallns distilled water One large clear pitcher r beaker Three small clear glass/plastic cntainers Ammnia Vinegar Phenlphthalein slutin Fr each grup f students: Fur glass/plastic cups Eyedrppers and cntainers fr ammnia, vinegar, and phenlphthalein slutin Distilled water Prcedure: The fllwing image will help yu prepare the slutins and run thrugh the demnstratin: Cup 1 Cup 2 Cup 3 Cup 4 Preparatin: (D nt allw the students t see yu d this!) Fill Cup 1 halfway with distilled water. Add ne capful f ammnia int the distilled water. Add a little mre vinegar in Cup 4 than the pitcher has ammnia. Place 3-5 drps f phenlphthalein int Cup 3. Demnstratin: 1) Pur the cntents f Cup 1 int Cup 2 (Cup 2 will remain clear). 2) Pur the remainder f Cup 1 int Cup 3 (Cup 3 will turn pink). 3) Pur Cup 2 back int Cup 1 (Cup 1 will remain clear). 4) Pur Cup 3 back int Cup 1 (Cup 1 will turn the same clr f pink).

7 5) Pur Cup 1 int Cup 2 (Cup 2 will remain pink). 6) Pur Cup 1 int Cup 3 (Cup 3 will remain pink). 7) Pur Cup 1 int Cup 4 (Cup 4 will turn clear). 8) Pur Cup 2 back int Cup 1 (Cup 1 will remain pink). 9) Pur Cup 3 back int Cup 1 (Cup 1 will remain pink). 10) Pur Cup 4 back int Cup 1 slwly (Cup 1 will turn clear). Student rules: Student grups are t be encuraged t take very gd ntes abut what the demnstratr is ding. They will be asked t perfrm the same demnstratin t the instructr. N mre than three drps f any fluid can be placed within their cups. All cups must be rinsed with distilled water prir t every trial. Tap water will likely spil the results. Hints: Yu may want t help the students by infrming them that Cup 1 cntains a slutin f water and ne f the three chemicals. Furthermre, yu can als help them by asking hw they culd determine what chemical causes the phenlphthalein t turn pink and which ne can make it turn back t clear.

8 Simulating the mst frightening frm f defense imaginable Students will be challenged t create a mdel f phagcytsis amng white bld cells. Materials: 1 plastic shpping bag 1 pair f scissrs 15 cm f string, large rubber band, r tape 4 pieces f wrapped candy, peanuts, raisins, r ther item Prcedure: With the materials in hand, the students are challenged t get the candy int their bag accrding t the fllwing rules: The candy must enter thrugh a slid part f the bag. The inside f the bag may nt be directly pen t the external envirnment (which means yu cannt simply drp the candy int the bag.) The candies entering the bag must remain clustered tgether. Yu may wrk with yur hands in the bag t act as the inside f a cell. All materials must be used Explanatin: White bld cells are knwn as phagcytic cells due t their ability t cnsume freign pathgens within the bld. Within the lymph ndes are specific types f phagcytes called macrphages which are very efficient at engulfing and destrying pathgens that find their way int the lymphatic system. The main prblem that ne has t cnsider is hw a cell such as a macrphage can ingest such large bjects withut the use f a muth r ther cavity t ingest such materials. Imagine having t ingest a beachball hw culd it be dne? Macrphages utilize the prcess f phagcytsis in which the freign bject is engulfed entirely by the cellular membrane f the macrphage itself. This bject is brught int the macrphage surrunded by a pinched-ff area f its wn cellular membrane. The macrphage s membrane is never pened up t the utside envirnment. If this were t ccur, it wuld likely perish. This activity is very similar t the actins f a macrphage within the lymph ndes f ur bdies. The pictures belw will help yu slve the puzzle...

9 T dwnlad a cpy f this handut and many ther exercises, g t and click n the MOSAC2 links