The Propertiesof Water Margaret E. Vorndam, M.S. Version 42-0129-00-01

26 Jun The Propertiesof Water Margaret E. Vorndam, M.S. Version 42-0129-00-01

Question
The Propertiesof Water

Margaret E. Vorndam, M.S. Version 42-0129-00-01

LAB REPORTASSISTANT

Thisdocumentisnotmeanttobeasubstitute foraformallaboratoryreport.TheLabReport Assistantissimplyasummaryoftheexperiment’squestions,diagramsifneeded,anddatatables that shouldbeaddressedinaformallabreport. Theintentistofacilitatestudents’writing oflab reports by providing this informationin an editable filewhich can be sent to an instructor.

Exercise 1: Surface Tension

RESULTS

A. State your hypothesis. What do you think will happen?

Table 1: Results of Surface Tension Trials

Trial #

Paper Clip Weight, grams

Does it Float? Yes/No

1

2

3

4

5Compacted

6 + Detergent (optional)

B. Record the results of your trials in the Data Table 1 above.

C. Did the weight of the paper clip affectwhether it floatedor not? D. Did the size of the paper clip affectwhether it floatedor not?

E. Did the shape of the paper clip affectwhether it floatedor not?

F. Optional:Did the additionof detergent influencethe flotationof the paper clip? Explain.

QUESTIONS

A. Why must the paper clips, tweezers, and bowl be clean? B. If one paper clip did not float,what might be a reason?

C. Was your original hypothesis supported or refuted?

DISCUSSION

A. Givetwoexampleswherethesurfacetension ofwaterisimportant.Whyisitimportantin these examples?

B. Wouldotherliquidshavethesamesurfacetensionproperty? Whyorwhynot?Howmight you test this (for instance, the behavior of a paper clip and olive oil)?

C. Is there a limit to the tensile strength of the water surface? Explain.

D. What experimental variables are important to consider when doing this exercise? E. What is the purpose of this exercise?

Exercise 2: Capillary Action

RESULTS

Table 2: Results of Capillary ActionExercise

Capillary Tube Internal Diameter, mm

Height of Liquid, cm

A. State your hypothesis. What do you think will happen? B. Record the results of your exercise in the Data Table 2.

C. Recordtheaverageresultsofatleastthreeotherstudents’exercisesinatablelikeTable3. Why is it important to note how many data sets (N) are used in the average?

N (number of data sets averaged) =

Table 3: Results of Capillary

ActionExercise

Capillary Tube

Internal

Diameter, mm

Height of Liquid, cm

D. GraphyourdataresultsfromTables1and2inascattergraph,linegraph,orbargraphsimilar to thegraphlayoutinFigure1.Alsopresenttheaverageresultsoftheother students’datausing a secondscatter, lineorbaronthesamegraphsothattheresultsofbothyourdataandother students’datacanbecompared.Thegraphshouldpresenttwoseries ofdata, yourresultsand the average students’ results, with Capillary Tube Internal Diameter on the x-axis, and height of liquidon the y-axis. Note: Do the graph by hand, or you may use a graphingprogram, and copy the resultinggraph to your work area. Place your graph here:

E. Whatistheadvantageofcomparing yourdatatothatoftheotherstudents’data?Which set of data would you trust the most? Why?

My data from Table 1 is recorded in

(student to specify color of line)

Otherstudents’averagedatafromTable2arerecordedin (studenttospecifycolorof line)

QUESTIONS

A. What did you observe at the end timeof the exercise?

B. What caused the differencein the results that you obtained?

C. How did your outcome compare to that of the other students?

D. Wastherealinear relationshipbetweenInternal Diameterandtheheightofthewater?What might explain this?

E. Was your original hypothesis supported or refuted?

DISCUSSION

A. Give two examples where the capillary actionof water is important. Why is it important?

B. Would other liquids have the same property? Why or why not? How might you test this?

C. Bloodinourbodies travelsthroughcapillariesofdifferinginternaldiameters.Thismeansthat ourheartcanworklesshard,sincebloodcontainswateraspartofthefluid, andthecapillary action of water in tubes helps to move the blood along.

1. Whydoesbloodpressureriseaspatientsexperience theprogressionofatherosclerotic disease?

Doesthisseemtobecountertowhatyouhavelearnedaboutcapillaryaction?Howdo you explain the apparent discrepancy (note: see also c., below)?

2. Inplants,vascular systemelements called xylemandphloem arelineduplikelongstraws fromthe rootofthe plant tothe leaves.Thexylem ofplants moves water anddissolved nutrients up to the leaves. Can you suggest what aids the movement of water up the plant, in additionto the capillary action of water?

3. Why is it harder to suck a beverage through a small diameter straw than through a large diameter straw?

4. What experimental variables are important to consider when doing this exercise? What couldexplainthedifference inoutcomesbetweenyourdataandthedataofother students?

5. What is the purpose of this exercise?

Exercise 3: Density

RESULTS

A. State your hypothesis. What do you think will happen?

B. Record what actually happened here:

QUESTIONS

A. What did you observe in this exercise?

B. How does this outcome compare to what you observe about the actionof ice (the solidform of water) on liquid water?

C. Was your original hypothesis supported or refuted?

DISCUSSION

A. Why is it important that ice floats?

B. Give two examples where the property of water density is important.

C. Do all solids floaton their liquid forms? Why or why not?

D. The density of liquid olive oil is about 0.92. What can you say about the likely density of solid oil? Why?

E. Will olive oil floator sink if it is added to liquid water? Why?

F. What experimental variables are important to consider when doing this exercise?

G. Attempttofindanother puresubstance, likewateroroil,inwhichthesolidformfloatsonthe liquid form (Note: do not spend more than 5 minutes on this question!).

H. What did you learn from this exercise?

Exercise 4: SpecificHeat Capacity

RESULTS

A. State your hypothesis. What do you think will happen?

B. Whatdifferencedoyouobserveintheheightsofthefrozensolidoilandwaterascompared to the liquid forms prior to freezing? What might explain this result?

C. Record what actually happened in a table similar to Tables 4 and 5

Table 4: Results of SpecificHeat Exercise for Water

Ambient (Room) Temperature

in Which Exercise was Conducted, ºC.

Time, minutes

Liquid Collected, mL

All solid ice gone

Table 5: Results of SpecificHeat Exercise for Oil

Ambient (Room) Temperature

in Which Exercise was Conducted, ºC.

Time, minutes

Liquid Collected, mL

All solid oil gone

D. GraphyourdataresultsfromTable4and5inagraphlikeFigure2.Useascattergraphor progressivelinegraph,withTimenotedonthex-axis,andmLofliquid collectedonthey-axis.You shouldhavetwoscatter plots orlinesonyourgraph(nottwoseparategraphs)—oneforwater and oneforoil.Note:youmayuseagraphingprogram,andcopytheresultinggraphtoyourwork area. Place your graph here:

E. Calculatethemeltingrateforeachofwaterandoil.Themeltingrateisequaltotheslope ofeachofthe separatelinesofyourgraph,oneforwater, and oneforoil.Theeasiestwayto calculatetheslopeforeachistouseyourgraphing program,andaskittodetermine thetrendline for you, as follows:

F. Shareyourmeltingrateforwaterandtheoilwithotherstudents,ifpossible. Makesureto also obtain the ambient (room) temperature from the other students. Why?

Table 6: Comparison of MeltingRates for SpecificHeat Exercise

Results Reported By

Water, mL/min

Oil, mL/min

General Ambient

Temperature, ºC.

Student

Student A

Student B

Student C

Student D

Average =

QUESTIONS

A. Was your original hypothesis supported or refuted?

B. Whatdoyouobserveconcerning theplotlineoftheoilversustheplotlineofthewater? What does this mean?

C. Howcloseisyourmelting ratetothemeltingratesreportedbyatleastthreeotherstudents for the water and for the oil?

D. Generally,whatmightyou concludeabouttheamountofspecificheatneeded tomelt50mL

of water versus 50 mL of oil?

E. Howcould youexplain thedifferencesin yourdataobservationsastowhenthewaterandoil began to melt?

F. Whatexperimentalvariables areimportanttoconsider whendoingthisexercise?Whatcould explain the differencein outcomes between your data and the data of other students?

DISCUSSION

A. Howmightyoudesignasimilarexperimenttodeterminewhetherthespecificheat(amount of heat required to raise 1 gram of a material by 1 ºC) of one substance is more or less than anothersubstance? Whatvariablesmustyouconsiderinthedesign ofyourexperiment?Give anexampleofsuchanexperimentthat comparesthespecificheatsfortwodifferentsubstances.

B. Analternative energy-savvypersondecidestouse55gallondrumsfilledwithliquidtowarm her house at night in the winter. She has to make a decisionaboutwhat liquid willbe the most efficient atstoringheatfromsunlightthatshinesonthedrumsduringtheday.Shouldsheuse water or oil in the drums? Why?

LABORATORYSUMMARY

What have you learned from doing this laboratory?