fermi questions

CRUCIBLEMagazine of the Science Teachers’ Association of Ontario

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LOOK UP... WAY UP: CANADIAN ASTRONOMER GETSRARE VIEW OF THE UNIVERSE

Volume 36 • 1September 2004

FEATURING:Improving ScientificLiteracy Using FermiQuestions

Emerging from theChrysalis

Careers in Science:Neonatal Nurse

Growing with yourStudents

New Science and TechWebsite for Students

Physics is Bananas!

Weather on the Web

Follow that Worm!

Learning by Accident

STAO Membership Report

ELEMENTS:Aircraft Lift

Greening the WayOntario Learns

Goggled Science

PAGE 15

STAO/APSO 2004Managing Change for Successful Learning

November 11-13, 2004Featuring a variety of fabulous featured peakers and incredible topics!

Jack Bacon – On the Lunar Mars Push and History in the MakingPhilip Currie – The Dinosaurs of Canada: Scientific, Cultural and Educational IconsJay Ingram – Grabbing their Attention: Why Not Use the Science of Everyday Life?Bob McDonald – In the Pit, On the Peak: The highs and lows of Canadian ScienceJoe Schwarcz – Science & the Paranormal and To Eat or Not to Eat... that is the QuestionIvan Semeniuk – Seven worlds in Seven Days

...plus over 200 other speakers!!!

DAILY SPECIAL EVENTS: STAO/APSO Mixer and the banquet on ThursdaySTAO/APSO Celebration Luncheon on Saturday

STAO/APSO AGM on Friday

Register early and save on your registration fees! See www.stao.org for full details and watch for your conference planner in the mail!

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3September 2004 CRUCIBLE

CONTENTS

DISCLAIMERThe enclosed information is to be considered as suggestions and recommendations only, and is neither to be considered as legal requirements nor as the policy of the Science Teachers’ Association of Ontario.The conclusions, findings and opinions expressed herein are those of the individual contributors and not of the Science Teachers’ Association of Ontario. Neither the Science Teachers’ Association of Ontarionor the individual contributors may make any guarantee, warranty or representation as to the correctness or sufficiency of any of the information herein. It can neither be assured that all necessary warningsand precautionary measures are contained herein, nor that additional information or measures may not be required due to particular exceptional circumstances, or because of local present, new or modifiedlegislation in any region where the enclosed information is followed. Neither the Science Teachers’ Association of Ontario nor the individual contributors on behalf of themselves, their agents, subcommitteesor anyone acting on their behalf assume any responsibility for any of the material published herein, and both the Science Teachers’ Association of Ontario and the contributors disclaim any liability in negligenceor otherwise for any injury, loss or damage of whatever nature resulting from the use of any of the material herein.

Crucible is published five times a year by the Science Teachers’ Association of Ontario.Issue dates are September, November, January, March, and June. ISSN 0381-8047. Canada Post Canadian Publications Mail Sales Product Agreement #491314.

Undelivered issues should be returned to: STAO Membership Office, The Science Teachers’ Association of Ontario, Box 771, Dresden, Ontario N0P 1M0

Individual membership in STAO includes a subscription to both Crucible and Elements. For membership rates please turn to page 39. Send cheque or money order to STAO Membership Office, The Science Teachers’ Association of Ontario, Box 771, Dresden, Ontario N0P 1M0. Change of address should be made to the preceding address at least six weeks prior to moving in writing, by telephone at1-800-461-2264 or by fax at 519-683-2473.

All rights reserved. Articles may be reproduced, but requests for permission should be made directly to the author. The author’s address will be supplied by the Editor if it does not appear with the article.

Crucible welcomes both readers’ comments and articles. Articles should be typewritten clearly or word processed. Submissions on CDs or by email would be greatly appreciated. Articles should not be morethan 2 500 words long. Include with articles approximately 25 words of the author’s biography AS WELL AS the grade level for which the information may be useful. We also invite head-and-shoulders, black-and-white authors’ photographs, as well as other photographs which would complement the contents of the submissions. If articles are accepted for publication, we reserve the right to make appropriate editorial changes in style and length. Please send all correspondence to Shayla Gunter-Goldstein, Assistant Editor, Crucible magazine, c/o Ste. 307, 8 Roanoke Rd., North York,Ontario, M3A 1E6. Email: [email protected]. Writers should supply full name, school address, and home and school telephone numbers.

140-Foot Telescope. The NRAO 140 Foot Telescope was completed in thespring of 1965. Located in Green Bank, West Virginia. Used with permission.National Radio Astronomy Observatory, a National Science FoundationFacility, managed by Associated Universities. Inc.

Crucible is printed on recycled paper.

President’s Message ........................................................5

Improving Scientific Literacy Using Fermi Questions ....7

Emerging from the Chrysalis: 10 Tips for First

Year Teachers ..........................................................10

The Hardy Weinberg Equilibrium and Chi-Square Test of

Significance: Part II – Practice Questions ..............12

Careers in Science: Neonatal Nurse Nancy Yeh............13

Canadian Astronomer gets

Rare View of the Universe ......................................15

NASA Brain Bites Provide Answers for

Curious Minds..........................................................17

Growing with Your Students ..........................................18

Just for Fun from the STAO/APSO Virtual Library ........23

NRC Launches New Science and Tech Website for

Students ..................................................................24

Fun with Pennies ............................................................25

Physics is Bananas ........................................................27

Weather on the Web: From Observations

to Explanations ........................................................28

STAO Hot Website: Rubistar is for you! ........................29

Follow that Worm! ..........................................................30

Learning by Accident ......................................................33

Safety Q & A ..................................................................34

Elements ....................................................................Insert

S

ON THE COVER

4 CRUCIBLE Volume 36 • 1

STAO BOARD OF DIRECTORS: 2004 - 2005

PRESIDENTJohn Henry(905) [email protected]

PAST-PRESIDENTMaurice Di Giuseppe(416) [email protected]

1ST VICE PRESIDENTChuck Cohen(905) 787-8772, xt. 615; [email protected]

2ND VICE PRESIDENTStephanie [email protected]

TREASURERDr. Greg Finn(905) 688-5550 x.3528; [email protected]

SECRETARYJoanne Harris(905) [email protected]

PROFESSIONAL DEVELOPMENTCOORDINATORMalisa Mezenberg(416) [email protected]

SCCAO REPRESENTATIVEXavier Fazio(905) 632-6314 [email protected]

REGIONAL DIRECTORWuchow Than(905) [email protected]

MEMBER AT LARGEVacant

Executive Committee

REGION 1: THE NORTHERN REGIONSusan Robinson(807) [email protected]

REGION 2: THE WESTERN REGIONVacant

REGION 3: THE CENTRAL REGIONVacant

REGION 4: THE EASTERN REGIONDennis Paré(613) [email protected]

REGION 5: METRO TORONTOREGIONJulie Vander [email protected]

Regional Councillors

MEMBERSHIPCheryl Madeira(416) [email protected]

ELEMENTARY CURRICULUM Derek Totten(905) [email protected]

SECONDARY CURRICULUM Milan [email protected]

SAFETYDr. Ralph Chou(519) 888-4567, xt. 3741 [email protected]

INTERNAL RELATIONS Dr. Gino Ferri(519) [email protected]

STAOCOMRay ClementSee page 3: STAOCom Listings

EXTERNAL RELATIONSNaomi Epstein(416) [email protected]

CONFERENCE CO-CHAIR 2004Ian MacKellar(613) [email protected]

CONFERENCE CO-CHAIR 2004Chuck CohenSee listing in Executive Committee

CONFERENCE CO-CHAIR 2005Anita Ghazariansteja(416) [email protected]

CONFERENCE CO-CHAIR 2005Adrian yu [email protected]

SCIENCEWORKS CHAIRRalph [email protected]

VIRTUAL LIBRARY CHAIRDave [email protected]

COMMUNICATIONS EDITORIALCOMMITTEEMaurice DiGiuseppe(416) [email protected]

STAO WEBMASTERDan [email protected]

Committee Chairs

MINISTRY OF EDUCATION Denis McGowan(416) [email protected]

FRANCO-ONTARIEN Marc G. Lecompte(613) [email protected]

FACULTIES OFEDUCATION Peder Nielsen(519) [email protected]

CAAT REPRESENTATIVEVacant

UNIVERSITY REPRESENTATIVEDr. Greg FinnSee listing in Executive Committee

Institutional RepresentativesEXECUTIVE ASSISTANTPaul WeeseSTAO Membership OfficeBox 771, Dresden, ON; N0P 1M01-800-461-2264; FAX [email protected]

MANAGER, STAO SCIENCE STOREIan MacKellar(613) 348-3628; FAX (613)[email protected]

HONOURARY PRESIDENTErminia [email protected]

P RESIDENT’S MESSAGE

My name is John Henry and I am thenew President of STAO/APSO. Ireceived my chemistry degree at theUniversity of Hull in England where Itaught in a Grammar School for 4years. In 1969 I moved to Hamiltonand taught in a number of secondaryschools and became Head ofDepartment and also SpecialEducation Consultant. For nine years Iwas also a Science Consultant incharge of science from JuniorKindergarten to OAC. This is my 40thyear of teaching and during the last sixyears I have been teaching onesemester per year at WestmountSecondary School in Hamilton.

During the last six years I have beenan active member of the STAO/APSOSafety Committee giving manyworkshops on ‘Be Safe.’ When the‘Stay Safe’ project was introduced Ibecame the Project Manager andoversaw its successful completion.

There are many challenges forSTAO/APSO in the next year. Theprincipal one is the review of the newscience curriculum which will start inSeptember 2005. STAO has to beready to present your views to theMinistry and we will be doing this in avariety of ways, especially at theconference. Teachers will be asked to

fill out questionnaires and yourcomments will help us greatly in ourpresentation.

Alan King’s study on retention ofstudents has had a considerable impacton the Minister. Over the summer wehave had a writing team preparescience articles which can be used tohelp students develop literacy skills.They will be available on theSTAO/APSO Website (www.stao.org)in the early fall. We hope yourstudents will benefit from this project.

The STAO/APSO Conference will beheld in Toronto at the Doubletree

International Plaza Hotel onNovember 11 – 13, 2004. The themefor this year’s conference is‘Managing Change for SuccessfulLearning.’ The conference planner iscomplete and as expected, theProgram Committee has done anamazing job. You should have re-ceived the conference program alongwith this issue of Crucible. I urge youto read through it early so you mayplan your conference visit. With over200 speakers, I’m sure you’ll want totake in many of the excellent sessionsbeing offered. Don’t forget to bookyour hotel room early if you areattending from outside of Toronto.

We were able to obtain a generousgrant from Merck to produce anotheredition of the calendar for ElementarySchool teachers. It will be sent toevery elementary school in the earlyfall. We hope that you will find it veryuseful and be able to use it with yourclasses.

I am looking forward to a verychallenging year and hope to meetyour needs as science teachers. Feelfree to contact me through theSTAO/APSO First Class site:[email protected]. I wish you all a very successful andenjoyable year.

John Henry

STAO President

Mark your calendar today, and don’t miss out on thisexcellent professional development experience!!

Get ready for STAO/APSO 2004!November 11-13, 2004

For full details, visit www.stao.org

5September 2004 CRUCIBLE


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MOVING?QUESTIONS • COMMENTS • CONCERNSwho to call . . .

Let STAO know...

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Please forward this information to:STAO Membership Office

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or email: [email protected]

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MOVING?!Crucible – General

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ProfessionalDevelopmentMalisa Mezenberg(416) 367-8033 (home)[email protected]

Deadline schedule for Crucible & ElementsPlease make note of these dates on your calendar!

Issue Number Deadline

November 2004 36.2 Sept. 7 ’04January 2005 36.3 Nov. 5 ’04March 2005 36.4 Jan. 5 ’05

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September 2004 CRUCIBLE 7

Improving Scientific Literacy UsingFermi Questions

««« By Michael De RobertisMichael De Robertis teaches in the Department of Physics & Astronomyat York University. He may be reached at: [email protected]

This article is based on a presentationgiven by the author at the 2003 STAOConference.

IntroductionWe all have some notion of whatconstitutes scientific literacy; it is abasic familiarity with how the worldworks. Scientific “common sense,”some might call it. This term alsoconnotes a basic facility with conceptsin mathematics. It goes without sayingthat at this point in history and in ourculture, a truly literate individual mustalso be scientifically literate.

Major efforts are underway in thedeveloped world at this time toimprove scientific literacy. Indeed, theNatural Sciences and EngineeringResearch Council of Canada(NSERC), one of the most prominentagencies that funds scientific researchin this nation, has recently announceda program – Centres for Research inYouth, Science Teaching and Learning(CRYSTAL) – aimed specifically atthese concerns.

The economic and politicalconsequences of a scientifically literateworkforce (or a lack thereof) havebeen frequently addressed; a scientif-ically literate person can participatemore effectively in society. A scienceteacher, however, has a moreimmediate focus: enhancing students’scientific literacy improves theircritical skills, their general reasoningcapabilities, and gives students a senseof whether their answers arereasonable. Additionally, scientificallyliterate individuals are less apt tosuccumb to growing pseudoscientifictemptations in our society — fromalternative medicine to psychics.

It is important to appreciate thedistinction between scientific literacy

and technological literacy. The abilityto program a VCR or DVD is anexample of technological literacy.Understanding how a VCR or DVDworks in the simplest scientific terms,however, is of greater importance andis an example of scientific literacy.

MotivationIt is both illuminating and entertainingto provide a few examples of scientificilliteracy or innumeracy taken fromeveryday experiences to motivate aprogram to improve students’ skills:

1. To compete with the quarter-poundburger of a well-known fast-foodchain, another fast-food chain offeredits customers a “one-third poundburger.” The new one-third poundburger didn’t sell well because toomany people thought that a quarter-pound burger was bigger than a one-third pound burger.

2. In a radio interview, a personextolling the virtues of eating peanutbutter claimed that the averageNorth American eats 100,000 peanutbutter sandwiches in a lifetime.

3. A single bankruptcy lawyer in theUSA in 1990-91 billed clients for anaverage of 1,200 hours of work amonth – from a low of 851 hours, toa high of 1,547 hours.

4. “A million, a billion, a trilliondollars; what does it matter, so longas the problem is solved.”

5. In 1990, an advocate for thehomeless claimed that homelesspeople die at the rate of 45 eachsecond in the USA.

While the first three examples mayseem almost trivial, there is no doubtthat scientific illiteracy can have veryserious consequences as the last twoclearly show. Perhaps the mostdisastrous example was China’s so-called “Great Leap Forward” in themid-1960s which led to the deaths oftens of millions of people. Many ofthese perished in part because of thescientifically illiterate policies of MaoZedong.1

Fermi QuestionsThe Fermi Question, sometimesknown as the “back of the envelope”question, was named after 1938 NobelLaureate (in Physics), Enrico Fermi.Fermi used to challenge his studentswith questions that involved estimationcoupled with an understanding offundamental scientific concepts.Classical Fermi Questions (FQs)include, how many barbers are there inNew York City, or how many pianotuners are there in Chicago?

Scientists and educators agree that ajudicious employment of FQs canenhance students’ scientific literacy atalmost any level; from elementaryschool through to graduate school. Itcan be quite an empoweringexperience for students to realize thatso much about the natural world canbe quantified and is well within theirpowers of reasoning! Teachers arefortunate that most students find FQsrather entertaining if administeredregularly at the appropriate level.

1 The New Emperors: China in the Era ofMao & Dengby Harrison E. Salisbury,Little Brown & Company, Boston, 1992.

continued on page 8...

SCIENCE IN EDUCATION


How to BeginStudents have been understandablyconditioned to believe that precision isa hallmark of science. It can come as ashock to some students, therefore, thatin the case of FQs the answer is ofsecondary importance to the method ofarriving at an answer.(I write “ananswer” rather than “the answer,”since a range of answers isacceptable.) This point has to beemphasized repeatedly.

By “method,” it is meant charting arational and logical approach toachieving an answer in the appropriatecontext. An answer is arrived at byfolding in various assumptions andestimating certain quantities whererequired.

Students at all levels should beencouraged to estimate quantitiesinvolving familiar situations. Forexample, at the senior elementarylevel, students may be asked toestimate things like:• the number of students in their

school, • the number of bricks in the school, • the length of the perimeter of the

schoolyard, • the number of tennis balls that

would fit in the classroom,• the number of blades of grass on the

field, • the number of potato chips eaten in

the school cafeteria daily, etc.

Questions at the elementary levelshould always be tailored as closely aspossible to the local context.

More mature FQs require students tobe comfortable with fundamentalunits: length, mass and time, as well asscientific notation. (A desirablebyproduct of practicing FQs is thatstudents gain a deeper appreciation ofthe importance of units and,ultimately, of dimensional analysis to

solve science problems.) There is nodoubt that a little time spent on FQswill pay significant dividends in thelong run.

How Many Dentists are therein Ontario?It is useful to illustrate how oneapproaches systematically a simpleFQ since the most frequent questionstudents ask when introduced to FQsis, how do I start? One starts bydevising a plan for arriving at ananswer, listing all assumptions alongthe way, and then carrying it out.

Basic assumption:there are justenough dentists to accommodateOntarians if they work a regular (40-hour) work week.

Plan:• Determine how many patients the

average dentist sees each year• Divide the total population of

Ontario by this number to arrive atthe number of dentists who could besupported

In order to find how many people theaverage dentist sees annually, wemake the further assumptions that atypical dentist appointment lasts forabout 1 hour and that people visit theirdentist twice each year. The solutionnow follows straightforwardly:

Solution:• A dentist treats 40 patients per week

(40 hr/1 hr)• Or 1,000 patients per half year (40

patients/week x 25 weeks/half year)• Since there are 10,000,000 children

& adults in Ontario, there should be10,000 dentists (10,000,000/1,000)in Ontario

How close is this? According to theRoyal College of Dental Surgeons ofOntario, this is well within 50% of the

actual figure. But I wish to emphasizethe following:a) There is no exact answer.

Providing the logic underlying theplan is correct and the estimationis reasonable, a range of answersis acceptable. So it doesn’t matterif dentists actually work only 35hours per week on average or takesix weeks vacation annually, etc.

b) Solving FQs often requiresstudents to expand their horizonsbeyond what is normally expectedof them (e.g., to know thepopulation of Ontario). Moreover,students will soon be able toidentify examples of sets with onethousand elements (population ofa large school), one millionelements (population of a fairlylarge city), one billion elements(population of the westernhemisphere), etc.

More Involved QuestionsThough it may take some time tothink up challenging FQs to give aclass, it is well worth the effort.Seeing a few examples is alwayshelpful. Consider then the followingquestions that may be appropriate forsenior elementary school or the firstyears of high school (with order ofmagnitude answers or hints inbrackets):

a) How many hairs are there on yourhead? [100,000]

b) How many times is a basketballdribbled in a game? [3,000]

c) How many words are in theschool library? (100,000words/book)

d) How many hours have you sleptin your life so far? [40,000 forteenager]

e) How much garbage is producedannually in your school? (~100kg/student/yr)

S CIENCE IN EDUCATION

Fermi Questions (...continued from page 7)


f) How far does the entire studentpopulation travel daily within theschool? (~1 km/student/day)

g) How many words are spoken inCanada in one day? [50 billion]

h) How much money is spentannually in Canada on pets? [$10billion]

i) How many grains of rice are eatenmonthly in China? [30 trillion]

j) What is the combined annualsalary of all professional athleteswho play team sports in NorthAmerica? [$3 billion]

k) What is the total distance ahockey puck travels in a singleNHL game? [10 km]

l) How many words are printed inall copies of Canadian newspapersin a typical business day? [2 trillion]

(Note that some of thesequestions/answers have importantsocial consequences and so couldstimulate discussions beyond thescience or math classroom.)

FQs may also include a scientificcomponent, though these are normallyreserved for more senior high schoolclasses:

a) Which exerts a greater pressure; awoman in high heels or anelephant standing still? [woman]

b) How many kilograms of watercontain about as many moleculesas there are drops of water in allthe oceans? [~1 kg]

c) How many ants does an anteatereat in its lifetime? [40 million]

d) How many molecules of air oncebreathed by Julius Caesar were inyour last breath? [~1,000]

e) If the iron in Earth’s core weremade into a long wire with across-sectional diameter of 1 mm,how long would the wire be?[5e25 m]

f) What is the minimum amount of

energy used to make hot coffee/teaconsumed by people in Ontario onan average day? [2 trillion J]

g) What volume of carbon dioxide isexhaled by Earth’s populationdaily? [ 100 trillion cubic m]

(I am indebted to the AmericanJournal of Physicsfor some of thequestions above.)

ConclusionsFermi Questions can be used to greateffect in the math and scienceclassrooms of elementary and highschools (not to mention universityclassrooms). Their regular usage canlead to students with enhanced critical-thinking/reasoning skills and a greaterfacility for estimation – scientific“common sense.” Given some thoughtand placed in the appropriate context,students find Fermi Questionsentertaining, making their introductioninto the classroom easier on theteacher.

Finally, at the 2003 STAO Conference,I challenged the audience of teacherswith the following five FQs. Howwould you fare? See the shaded boxbelow for the “answers.”

1. How many snowflakes fall onManitoba annually?

2. How many ice cubes can be madefrom ice occurring naturally onEarth?

3. If the hairs from the fur of everycat in Ontario are placed end toend, how long would the singlestrand be?

4. How many notes are played by allthe instruments combined during aperformance of Beethoven’s FifthSymphony?

5. The carton containing a 60-Wattlight bulb promises a lifetime of500 hours. How many moles ofphotons does the light bulb emit inits life?

Fermi Questions (...continued from page 8)


Answers(As determined by the author who sometimes cheated to ensure his estimateswere as close as possible!):1. 2 x 1019 snowflakes2. 3 x 1021 ice cubes3. 1 x 1010 metres (or 30 times the Earth-Moon distance)4. 1 x 105 notes (there really are apparently 64,137 notes)7. 1 x 103 moles of photons

STAO has set up a First Class account called “[email protected]”.Messages sent to this account go directly to Paul Weese,

Executive Assistant of STAO.

We’re looking forward to hearing from you!

Need to reach someone at STAO?


Teachers often expect that after thescramble and stress of their first yearon the job, they will attain masteryafter the first couple of years. I believethis is not true. Many people plateauand do not improve appreciably evenif the desire is there. Consciousplanning to improve your practice canlead to long term change. Make raisingthe bar each year a habit. Thefollowing are tips that teachers can useto help improve themselves.

My Top Ten Tips for FirstYear (and other) Teachers1. Find a mentor ASAP.I can’t

emphasize this enough. Someschools have an official mentorprogram but if not, there is usuallysomeone in your own departmentthat will unofficially take youunder their wing and give yousuggestions and help. Mostteachers are willing to provideadvice on how to achieve bestpractice.

2. Make a list of things to master:goals for this year and next year.Call it an Annual Education Planor a list of goals, but students andteachers alike should be makinglists of long term and short term,specific, attainable goals.Remember S.M.A.R.T. goals?They are: S=specific,M=measurable, A=attainable,R=realistic and T=tangible. E.g. Ifyour goal is to improve yourclassroom management skills, howwill you go about doing it? Whenwill this goal be reached? Howwill you know if you haveimproved? Usually, we havevague goals about “doing better”such as improving classroom

management, finishing courses,improving parental contact,making a course more hands-on,being more on top of one’smarking, indeed, being more ontop of everything! If you have afour-day turnaround for marking,could you make it a two-dayturnaround? Do you want toimprove parental contact? Howabout taking one prep time aweek, making a list of 10 studentsabout whom you are concerned,and calling the parents or sendingout letters of concern.

3. Set the pace.What you start outdoing, you will continue doing.Set a minimum standard foryourself. Give yourself practicalshort-term goals. An examplemight be to teach one chapter perweek, which includes onelaboratory activity, onedemonstration and a test or quiz.Be practical! Do not have all yourlab days be the same day for everyclass. Take the ebb and flow ofschool life into account. OnMondays, students are tired. Thisleaves Tuesday, Wednesday,Thursday which are (in myopinion) peak theory days.Thursdays and Fridays are optimallab days and it gives studentssomething to look forward to. Besensitive to the students. Theycannot handle 75 minutes ofdroning, multiplied by 4 classes.

In a week give them one classwhere they are are teachingthemselves (eg. doing worksheets,

learning to do crib notes from thetext, solving problems on theirown, doing mind maps, etc.) orengaging in cooperative learning(Monday), and perhaps have ademo-lesson on Tuesday. OnWednesday have a regular theoryday, Thursday have some theoryplus a test or quiz, and on Fridayend by complementing the week’stheory with a practical labcomponent. It could be a fullperiod lab with a full write up dueor it could be more of a lessonfollowed by a process lab such asmaking soap or bath bombs, icecream (heat transfer, Gr. 11Chemistry) or silly putty (OrganicChemistry). If you’re unable to doa “cool” lab or make a product ona Friday (who can come up forsomething every Friday?), at leasttry to light something on fire orexplode something. It occurred tome that students take science yearafter year, just hoping and yearningfor a good explosion. A gooddemonstration is the Thermitereaction (see Shakashiri’s demosfor more details1) – for grades 9,10, or 11 chemistry as a singledisplacement reaction with goodconnection to societal implications.The Acetylene bomb is anotherideal demonstration. If you plan itright, you can fit in a lot of neatstuff to complement the theory andstill finish the curriculum.

4. Mix it up – You don’t have toalways do a mega-lab each time.Download your workload! Have a


Emerging from the Chrysalis: 10 Tips forFirst Year Teachers

««« By Leila KnetschLeila Knetsch is a Biology/Chemistry teacher at Winston ChurchillCollegiate in the TDSB (Scarborough).

1 B.Z. Shakashiri, Chemical Demonstrations: A Handbook for Teachers of Chemistry, Vol. 1-4, University of Wisconsin Press. Also: Science isFun Website: www.scifun.chem.wisc.edu



partial write-up sometimes; it willbe easier on the students and youin terms of workload. You alsodon’t always have to have a full-period lab. Sometimes it’s great todo a mini-lesson/mini-labcombination. Using ademonstration is a great way tocapture student interest and addtheory, without all the work of alab. Besides the entertainmentvalue and the interest created,demonstrations are also awonderful way to get through tothe visual learners out there.

5. Make a month-at-a-glance plan.Print off calendar pages from yourcomputer and determine generallywhat you are going to teach onwhich days during the month for aparticular subject. Write in penciland revise as you go along. Thisis helpful as you don’t have to askyourself “what am I going toteach tomorrow?” Instead, thequestion will be “how am I goingto teach/get them to learnexpectation x/y/z?” Also, you willfind that you will finish more ofthe course if you plan ahead. Youwill have time to do more labs,activities and hands-on learningthat your students (and likely you)long for. Your colleagues might beskipping things because they haverun out of time, but you will beable to fit more material inbecause you planned around theassemblies, shortened days, etc.

6. Scavenge and sort continually.Continue to scavenge for ideas,labs, activities, demonstrations,worksheets, etc. from studentteachers, colleagues, the Internet,Crucible, etc. Have course binderswith dividers for every subject.When you find somethinginteresting and useful, file it in thebinder, under the appropriate unit.This helps you avoid a mad panicwhen you have to teach a newcourse. Instead you should have afeeling of excitement since you

get to use your “mined treasure.”Textbooks from other publishersand old textbooks from previouscurricula can also be a valuablesource of excellent labs,demonstrations and diagrams. Justbecause the curriculum haschanged does not mean that thescientific basics have!

7. Keep up to date and into thehabit of exchanging (notleeching!) with colleagues in yourschool and elsewhere. With themany people (student teachers,LTOs, etc.) moving in and out ofschools, this can be very simple.It’s easy to ask someone forsomething when you know thatyou have something that they wantin return. Inter-school mail makesthis a snap. It’s the old bartersystem. I will photocopy and sendto you five excellent demonstrat-ions for use in each of the Grade11 Chemistry units in exchange forsome interesting items for theGrade 12 Biology Homeostasisunit. Since we know our schedulesmonths in advance, there is loadsof time to make these offers.

8. Consider teaching your coursesalong a theme.I would suggest aSociety, Technology and theEnvironment (STSE) theme. It’s agreat way to help raise environ-mentally conscious young people.Don’t forget about STSE! As ayoung (or not so young) rookieteacher, there is a youthfuloptimism and concern for theenvironment and societal issues.Try to incorporate these into yourclasses. The theme is already in the

curriculum, although less so than inthe last curriculum where it wasweaved into every course inaddition to being covered in theenvironmental science and sciencein society courses which have sincebeen removed from the curriculum.Some teachers have themesrunning through their courses, andthey pull everything together usingthe theme as the backbone.

9. Take a trip to the library atOISE. A one-day trip to the libraryat OISE with some cash forphotocopying can be very exciting.Make it an annual event! Make alist of the courses you are teachingand some suggested topics andthen hit the stacks. There is somuch out there. Every year it’s agreat idea to load up on good ideas.The difference between a goodprogram and a great program isresources, resources, and moreresources. Don’t try to get yourcourses “in shape” and leave themas is for the next 30 years. The goalshould be to refresh and renew,starting on day 1. After the firsttwo years, when you are not asfrazzled by day-to-day survival,you will get bored unless you mixit up. Get beyond “survival” modeand onto “mastery” mode.

10. Find a shoulder to unload on.First year is a tough year and it ishelpful to have a confidant withwhom you can voice your fears, oron whom you can shed someoccasional tears. It can certainlyhave a buffering effect.

Good luck!

Science SilliesTeachers have forwarded these answers from test papers, essays, etc. They weresubmitted to science and health teachers by elementary, junior high, high school, andcollege students. From time to time, when space is available, Cruciblewill publishseveral of these items for your amusement.

“Vacuum: A large, empty space where the pope lives.”

“Before giving a blood transfusion, find out if the blood is affirmative ornegative.”


The Hardy Weinberg Equilibrium and theChi-Square Test of Significance: Part IIPractice Questions - Using χχ2 to test for evolution

««« By Seonaid DavisSeonaid Davis is Co-ordinator, Programs for Highly Able Students atHavergal College in Toronto. She is a regular contributor to Crucible.


Part one of this article appeared inCrucible, Volume 35.1, September2003. Refer to www.stao.orgafter thisissue is published, to see the completearticle.

How can you tell if a population isevolving or not? Use the χ2 test ofsignificance to help you decide.


Just because the observed allelic frequencies calculated from the originalgenotypic data are used to calculate the expected genotypic frequencies, youmight think that it will necessarily show that the population is in Hardy Weinbergequilibrium. Complete the following examples to show that this is notnecessarily true. Consider the following data. Is this population in Hardy Weinbergequilibrium? Use your χχ2 analysis to check.1

Remember to check your total population size.

The results from the χ2 test are non-significant. This means that thepopulation is in Hardy Weinbergequilibrium.

Consider the following data2. Is this population evolving? Use yourχχ2 test tofind out.

Remember to check your total population size (200).

Numbers of Genotypes Allele Frequenciesindividuals

MM MN NN p q

Observed 114 76 10 0.76 0.24

Expected proportions p2 2pq q2

Expected frequencies 0.58 0.36 0.06 Total value for χ2 test = 0.58

Expected numbers 116 72 12

χ2 = (o-e) 2/e 0.03 0.22 0.33 Degrees of freedom = 1

Numbers of Genotypes Allele Frequenciesindividuals

MM MN NN p q

Observed 152 0 48 0.76 0.24

Expected proportions p2 2pq q2

Expected frequencies 0.58 0.36 0.06 Total value for χ2 test = 191.17

Expected numbers 116 72 12 Degrees of freedom = 1

χ2 = (o-e) 2/e 11.17 72 108

The χ2 test gives a significant result.This means that the differencebetween the observed and expectedresults would not be expected tohappen by chance alone. The inferenceis that the population is evolving.

1 Adapted from: Crow, J.F. 1986. Basic Concepts in Population, Quantitative, and Evolutionary Genetics.W.H. Freeman and Co., Sand Francisco, CA.Pg 528-529

2 Adapted from: Crow, J.F. 1986. Basic Concepts in Population, Quantitative, and Evolutionary Genetics. W.H. Freeman and Co., Sand Francisco, CA.Pg 528-529

3 Source: R.A. Fisher and F. Yates, Statistical Tables for Biological, Agricultural and Medical Research (6th Edition)Oliver & Boyd, Ltd., Edinburgh

Degrees of

Freedom Probability

95% 90% 80% 70% 50% 30% 20% 10% 5% 1% 0.1%

1 0.004 0.02 0.06 0.15 0.46 1.07 1.64 2.71 3.84 6.64 10.83

2 0.10 0.21 0.45 0.71 1.39 2.41 3.22 4.60 5.99 9.21 13.82

3 0.35 0.58 1.01 1.42 2.37 3.66 4.64 6.25 7.82 11.34 16.27

4 0.71 1.06 1.65 2.20 3.36 4.88 5.99 7.78 9.49 13.28 18.47

5 1.14 1.61 2.34 3.00 4.35 6.06 7.29 9.24 11.07 15.09 20.52

6 1.63 2.20 3.07 3.83 5.35 7.23 8.56 10.64 12.59 16.81 22.46

7 2.17 2.83 3.82 4.67 6.35 8.38 9.80 12.02 14.07 18.48 24.32

8 2.73 3.49 3.49 5.53 7.34 9.52 11.03 13.36 15.51 20.09 26.12

9 3.32 4.17 4.17 6.39 8.34 10.66 12.24 14.68 16.92 21.67 27.88

10 3.94 4.86 4.86 7.27 9.34 11.78 13.44 15.99 18.31 23.21 29.59

Non significant Significant


χχ2 table of values3

Practice questions (...continued from page 12)

CAREERS IN SCIENCE

Neonatal Nurse: Nancy Yeh

««« By Leila KnetschLeila Knetsch is a Biology/Chemistry teacher at Winston ChurchillCollegiate in the TDSB (Scarborough).

Nancy Yeh is a full time RegisteredNurse (neonatal nursing) at Women’sCollege Hospital, where she hasworked for the past five years. Ms. Yehalso works part time at Toronto EastGeneral. Mrs. Leila Knetschinterviewed her for the first of a seriesof career profiles that she uses withher students.

Mrs. Knetsch: Would youplease describe your job?

Ms. Yeh: Some of my duties includebasic things like taking the vitalsigns of the babies (temperature,heart rate, respiration and bloodpressure). Also, I perform a headto toe assessment and look forcertain things like bruising, bodyproportion and skin colour –looking for jaundice, etc. I listenfor bowel movements and weigh

the babies’ diapers to make surethat their bowels are working well.In addition, I check the babies’breathing and if it is too fast ortoo slow, I put them on differenttypes of ventilators. Because it isthe Intensive Care Unit (ICU), Iam constantly monitoring thebabies.

I take care of babies that are bornprematurely, between 23 and 40weeks. In many cases, thesebabies have medical problems andneed to be monitored. Forexample, if a mother had a feverbefore she gave birth, then thebaby may need to have antibiotics.In another example, if a mother

has had a Caesarian section birth,the baby can’t get rid of the lungfluid and will have to stay in theICU due to respiratory distress.Babies also sometimes swallowthe meconium (waste) due tostress and have to be on aventilator for a short time. Infantsstay at the hospital from one dayto four or five months, dependingon their medical needs and howprematurely they were born.Nurses see the parents as well asthe babies on a daily basis. Somenurses try to work with certainbabies if they have a specialconnection with the family.



C AREERS IN SCIENCE

LK: What is your academicbackground?

NY: I have a Bachelor of Science,Nursing from the University ofToronto. It is a 4-year degree.

LK: What subjects should highschool students concentrate onto enter into the nursing field?

NY: Students should have a B+average and be strong inMathematics, Science andEnglish. Currently, to be a nurse,students need to take two yearsof Arts and Science and then twoyears of a Bachelor of Science inNursing. Some nursing schools inOntario are: MacMasterUniversity, University ofToronto, Ryerson University,Queen’s University, YorkUniversity (new program) andUniversity of Western Ontario.Another option is to do a college-university collaborative program.

LK: Why did you go into nursing?

NY: I have always enjoyed caring forpeople and thought that I had thequalities that would allow me tocontribute to the profession. Ithink this is something I learnedwhile growing up. My grand-mother took care of me and Iwanted to repay her. My grand-father was ill and I took care ofhim. I like the aspect of relation-ship building. Some patients yousee only once, while some pat-ients you see for months and getto know their families as well.

LK: What are some of the skillsneeded for nursing?

NY: You must have good communi-cation skills, be a good listener,and be a person that is veryrespectful of people withdifferent backgrounds.Sometimes people make choicesthat you might not agree with butyou have to respect their choices.

There are cases with babies thatare as young as 23 weeks oldwhere some people want you todo everything for them evenwhen the outcome is veryuncertain due to the fact that theyhave not finished developing.

You also need to be a good teamplayer, have excellent organiza-tional skills, good time manage-ment skills, and you need to showa lot of initiative in learning newthings and taking on tasks.

LK: What is one skill that you needto have as a nurse that you didnot expect?

NY: You have to be really organized.There is a lot of tracking ofpatients. There are so manypatients and if you cannotorganize your time to care forthem, that is a problem. Timemanagement is a must.

LK: What is the range of pay?

NY: The pay starts at $21-33/hr. Youget paid more for holidays, plusyou can get time and a half ordouble time pay if you workovertime.

LK: What is the worst part of yourjob?

NY: The worst thing is the shiftworkand the long hours. However,there is a plus side when you dotwo 12 hour days and two 12hour nights and then get fourdays off.

LK: What do you like best aboutyour job?

NY: I love watching the babies becomehealthier and grow, and then seethem go home. It’s reallysomething. It’s nice to know thatyou had something to do with them being alive.

EVENT CALENDARSeptember10, 17 Star Party @ Science North,

Sudbury, 8 p.m. Gaze at theplanets, the moon and the starsthrough powerful telescopes withthe help of Science North’sastronomer and volunteers fromthe Sudbury Astronomy Club.Access a recorded message forupdates: 705-522-3701, ext. 243.Admission is FREE for everyone!More info:http://sciencenorth.ca/plan/calendarofevents/

OngoingDynamic Earth at Science North.Go inside the planet to explorethe mighty forces of nature thatimpact people and culturesaround the world. Visit:http://dynamicearth.ca orhttp://sciencenorth.ca for moreinformation.

October4-8 4th World Conference of Science

Journalists, “Reporting thefuture: Journalism meetsemerging science.” Montreal.Visit: http://www.wcsj2004.comfor more information.

16-23 National Chemistry Week.Visit: www.cheminst.ca/ncw/index.html for more info.

23 National Mole Day. Visit:www.moleday.org/for moreinformation.

November11-13 STAO 2004. Managing Change

for Successful Learning.International Doubletree Hotel,Toronto. More details:www.stao.org

Neonatal Nurse (...continued from page 13)

So, you think that only professionalscientists get to do neat things? Thinkagain. On June 28 and 29, I (a teacherand amateur astronomer) had theopportunity to use the 40-foot radiotelescope at the National RadioAstronomy Observatory (NRAO)facility in Green Bank, West Virginia.

About 300 years ago, an explosionoccurred in our galaxy which signalledthe end of a massive star’s life. Thestar was 11,000 light years(104,068,800,000,000,000 km) away.The expanding shell of material whichremains from that explosion is knownas Cassiopeia-A and is movingoutwards at more than 16,000,000kilometres per hour. The remnant ofthat supernova explosion can still bedetected by astronomers today.

While Cassiopeia-A is only one ofmany galactic supernova remnants orSNRs, it is one of the objects which Iattempted to detect while in WestVi rginia. In the early morning hours ofJune 28, I swung a huge 12-metrediameter antenna into position.

Although the antenna looks like anoversized satellite dish, this antennadid not pick up satellite TV programs.It was peering 567,648,000,000,000,000,000 km into space at the constel-lation Virgo. I waited for 25 minutesas the antenna and Earth rotated underthe stars. Finally, a weak signal beganto appear. It continued to increase overthe next 5 minutes, then peaked, andthen in the following 5 minutes itdecreased and disappeared. I haddetected a radio source known asVirgo-A. Over the next several days, Idetected several other radio sources,some with unusual sounding nameslike 3C10 and W28. It was trulyexciting.

The NRAO is one of the world’spremier research facilities for radioastronomy. The NRAO operatespowerful, advanced radio telescopeswhich scientists from around the worlduse to probe fundamental questions in

astronomy and physics. TheNRAO operates the Robert C.Byrd Green Bank Telescope(GBT), the world’s largest (100by 110 metres) fully steerableradio telescope, as well as severalother telescopes. I used theNRAO’s 40-foot (12-metre)telescope for my study. Thesetelescopes are large versions ofthe satellite dishes found onmany homes.

While many people still think ofastronomy as a visual science,astronomers today also studyobjects that emit radio waves,infrared radiation, x-rays andgamma rays. Objects such as

Canadian Astronomer gets Rare View of the Universe

««« By Philip GebhardtPhilip Gebhardt teaches evening science courses at the PalmerstonCommunity School in Whitby, Ontario.

Cassiopeia-A act as huge radiotransmitters which send out signalsthat can be received here on Earth.These objects emit radio signals onfrequencies similar to FM radiostations, TV stations, cell phones andsatellites. Because of the enormousdistances, the signals are extremelyweak when they reach Earth. Largeantennas and sensitive receivers areneeded to detect the signals.

Last year, I studied x-ray astronomytechniques at the National SpaceScience and Technology Center(NSSTC) in Huntsville, Alabama in aprogram sponsored by NASA. TheNSSTC is a collaborative research andeducation initiative of government,academia and industry that serves as alaboratory for cutting-edge basic andadvanced scientific research. Thecentre also fosters the education of thenext generation of engineers andscientists.


SCIENCE AND SPACE $

Philip Gebhardt poses with the 40-foot (12-metre) diameter radio telescope

which he used to detect 3C218

Philip adjusts the motor control to position theNRAO’s 40-foot radio telescope to receive aradio signal from 3C10. The control room islocated underground to prevent signals from theequipment interfering with the telescopes. continued on page 16...


These are just two examples of theopportunities in science which areavailable to everyone today, but wouldhave been open only to professionalscientists 25 years ago. For me, usinga radio telescope at NRAO is like ahockey fan getting to play with theMaple Leafs or a baseball fan playingwith the Blue Jays.

In August, I headed back down southto do some work with an astronomerfrom the University of North Carolinawho runs a week-long workshopcalled Educational Research in RadioAstronomy.

Graham Mogford, an amateur radioastronomer in the U.K. who has alsoparticipated in a similar radioastronomy experience sums it up thisway, “It’s a great feeling actually usinga radio telescope and seeing your datacome in. I know when I was drivinghome from after first using it, Isuddenly thought, My God, I’veactually seen the structure of theMilky Way for myself, not just readabout it! It’s amazing when you stopand think about it.”

In 2001, Philip and his elementaryschool students conducted the GreatLoop Antenna Experiment in which

they built a square (3-metre sides) boxantenna on the lawn of the WhitbyPublic Library. They demonstratedhow it received AM broadcast stationsfrom as far away as New Orleans,Moncton and Winnipeg. (See Crucible,Volume 33.4 March 2002.) He has alsoworked with high school students atTrafalgar Castle School introducingthem to the radio detection of meteors.

Stellar Know-How

Want more information about radio astronomy? It’s as close as the Internet.You can uncover the “hows” and “whys” of radio astronomy athttp://www.nrao.edu/whatisra/index.shtml or take a short course in radioastronomy at http://www2.jpl.nasa.gov/radioastronomy/.

For images of radio telescopes and the objects which radio astronomers study,start with http://www.nrao.edu. This site will show NRAO telescopes, butthere are radio telescopes all over the world.

If it’s a hands-on approach you’re looking for, you can learn how to detectmeteors in “All Rock Radio” (Crucible, September 2001, p. 13) or Sky &Telescope(December 1997, p. 108). Or, you and your students can actuallydetect radio emissions from Jupiter and solar bursts from the Sun. To hearsignals from Jupiter, go to http://www.astro.ufl.edu/radioobs.html#Sounds.

Detecting Jovian radio signals is relatively easy. Hundreds of schools aroundthe world have been involved with NASA’s Radio Jove project. Seehttp://radiojove.gsfc.nasa.gov/

Rare view of Universe (...continued from page 15)

S CIENCE AND SPACE

In 2002, he received the ScienceTeachers’ Association of Ontario’sIrwin Talesnick Excellence inTeaching Award. This year, hereceived an Ontario Arts Councilgrant to teach pinhole photography.

Phil Gebhardt may be reached at 905-642-9718 or by email at:[email protected]

Crater Creator««« By Phil PlaitPhil Plait, a.k.a. The Bad Astronomer, publishes a Website and newsletteron astronomy. Visit the Bad Astronomy site at: www.badastronomy.com

So you’re out shopping for groceries,and you see in your rear view mirrorthat a 200 meter-wide iron asteroidhas impacted the ground 10 kilometersaway. Bummer! It’s sure to form animpact crater, create a firestorm, andotherwise ruin your day (as well asmelt the ice cream you just bought).

So, should you high-tail it in theopposite direction, or just go about

your business? Now these decisionsare easier to make! The good folks atthe Lunar and Planetary Laboratorieshave created a web page where youcan enter the parameters of the impact(asteroid size, composition, etc.) and itwill return a cheery and optimistic

look at how badly you’ll be killed bythe ensuing explosion. Fun for thefamily! Here’s the page:http://www.lpl.arizona.edu/impacteffects

The next time a student asks you,“How do you go to the bathroom inspace?” or “How long would a roundtrip to Mars take?” you can answerwith a NASA Brain BiteTM.

NASA Brain Bites are a series of 60-second video shorts to be used as alearning tool in helping educators andparents answer questions studentshave about space or aeronautics, or tointroduce classroom activities ontopics such as gravity, acceleration,motion, friction, Newton’s Laws andmore. Not only will these video shortshelp feed hungry minds but they willhelp students gain a betterunderstanding of how space scienceand aeronautics work.

Do your students know what launchwindows are and why NASA usesthem when sending a crew into space?If not, then let Super Bowl ChampionQuarterback, Kurt Warner help(spaceflight.nasa.gov/brainbite/launch). Warner explains that a launchwindow is similar to a play in football.For a space mission to meet its target,such as the moon or a distant planet, itmust take off in a certain time period.Warner explains the same is true infootball. When he throws the football,he doesn’t aim directly for histeammate, instead, he aims for wherethe ball will intersect his teammate’spath. Whether launching a football orlaunching a spacecraft, timing iscrucial. If you take off at the wrongtime you might miss your targetcompletely.

Students are also interested in findingout how astronauts train here on earth.NASA can’t send astronauts into spaceto work on the International SpaceStation if they have never had trainingin a simulated zero-gravityenvironment, so there are a few ways

space travelers can train. One way iswith a specially modified plane calledthe KC-135, also termed the “VomitComet,” (spaceflight.nasa.gov/brainbite/vomitcomet), and another isa giant swimming pool called NASA’sNeutral Buoyancy Lab, (spaceflight.nasa.gov/brainbite/underwater).Both give astronauts the necessarytraining they need to work adequatelyin space.

NASA Brain Bites caneasily go along with ascience lesson, and theyanswer questions in a waythat makes it easy formiddle and high school students tounderstand.

Teachers and parents can also get theirstudents’ directly involved withRocket Science at Home (RSAH),which works in conjunction withNASA Brain Bites. NASA hopes thiswill stem further interest, get studentsmore intrigued with science andhopefully take what they have learnedto explore more concepts of science ontheir own. By visiting the NASA BrainBites Website, students can learn howto build a hovercraft with the help of a

teacher or parent (spaceflight.nasa.gov/brainbite/rocketscience). Thisactivity can be integrated into theclassroom or as a Saturday afternoonproject. It’s a great way to get studentsdirectly involved with scienceprinciples and build something reallycool at the same time.

You can view the NASA Brain Bitevideos by visitingbrainbites.nasa.gov, where you willalso find links to supportingeducational material, including grade-appropriate activities that are mappedto national standards. Brain Bites canbe downloaded from the web at nocost, in presentation-level quality, foreducational purposes at any time.

In the near future, you will be able toobtain a videotape copy of NASABrain Bites for your classroomthrough NASA CORE at 1-866-776-CORE or core.nasa.gov, or throughyour area NASA Educator ResourceCenter. For any additional information,you may also contact Jenna C Mills at281-483-9261 or email the team [email protected].

Have you liked the stories and activities you’ve read so far?

If so, and if you’d like to be able to get other relevant and usefulactivities, worksheets and interesting articles for classroom discussion onan ongoing basis, you should join STAO today! You’ll get five issues peryear of Crucible and Elements, plus so much more! Visit www.stao.org formembership information.


S CIENCE AND SPACE

NASA Brain Bites Provide Answers for Curious Minds

««« By Jenna C. MillsJenna C. Mills is an Education Officer with the Johnson Space Centre inHouston, Texas.

This activity fits into the curriculum inthe following strands: Life Systems forGrade 3 (Growth & Changes inPlants), Grade 4 (Habitats &Communities), Grade 6 (Diversity ofLiving Things), Grade 7 (InteractionsWithin Ecosystems and Grade 8 (Cells,Tissues, Organs & Systems). It alsoworks into Earth & Space for Grade 3(Soils in the Environment) and Grade 5(Weather).

It also fits into Grade 9 Biology (thecurriculum specifically mentions bulbsin the academic stream, butreproduction is covered in bothacademic and applied streams). It canalso fit into Grade 11 Biology (geneticcontinuity).

Starting a school garden has manyadvantages, and this is the time of yearto capitalize on those advantages byplanting spring-flowering bulbs.Clearly, a garden enhances the sciencecurriculum. Students not only learnabout plant parts, their needs and thelife cycle of plants, they learn aboutsoil, aspects of weather and how plantsrelate to the animal kingdom andecosystems through a hands-on,applications-based activity. Scientifichorticultural names provide a greatintroduction to classification systems.All living organisms fit into a hierarchywhich includes kingdoms, divisions,classes, orders, families, genera andspecies. Your students will need toapply research and planning skills.Record keeping skills can be developedor reinforced. Beyond that, they learnhow to work together. When students

within your class, different classes oreven different grades work togetherand take time to get to know eachother, the results are a positive schoolenvironment. Ultimately, the studentswill have a beautiful garden of whichthey can be proud. That brings with it asense of accomplishment andsatisfaction. It also builds a sense ofcaring and of taking responsibility fortheir surroundings.

Unlike many science activities, bulbplanting is not a one-hour sciencelesson. It gives the students anopportunity to engage in an on-going,long-term project. One of the benefitsof planting a bulb garden is that itincludes a life lesson: postponedgratification. Students will not see theresults of the work they initially do forat least five or six months.The best part though is that bulbplanting is easy and almost failsafe.

What’s In a Bulb?The term bulb is often loosely applied toa range of subterranean food storageorgans. This covers tunicate bulbs(tulip), scaly bulbs (lily), corms (crocus),tubers (anemone) and rhizomes (iris).We’ll focus on the true bulbs (tunicateand scaly), corms and tubers since this islikely what you will plant with yourstudents at this time of year.

True bulbs produce foliage and rootsfrom a flattened area at the base of thebulb known as the basal plate. Thebulb itself is a compressed stem andthe fleshy scales are modified leaves.The scales have growth buds at theirbases and enclosed flower bud initialsthat will produce the coming year’s

flowers. Tunicate bulbs, such as tulips,daffodils and onions, have a paperyouter skin (the tunica) which is thedried remains of the previous season’sscales. Their scales are arranged inconcentric rings which radiate fromthe bulbs’ centre. Scaly bulbs – liliesfor example – do not have the paperyouter layer. Instead, they are composedof small, overlapping scales. Lilieshave many scales whereas fritillariahave only two or three.

A corm (crocus is one example) is theswollen base of a stem. A corm isusually rather flattened and solid. Likea tunicate bulb, it has a paperycovering which can be peeled away.Removing the covering reveals thegrowth eyes on the upper surface.A tuber (anemone is available in thefall) is the swollen part of anunderground stem. The tuber is usuallyrounded with various protrusions anddepressions which contain the buds(think of a potato).

Is It Science or Art Class?Planting bulbs is an opportunity to putyour students’ knowledge of light andcolour to work. Discuss whether tohave a monochromatic bed or apolychromatic bed. Should you useonly primary colours or should youinclude secondary and maybe tertiarycolours? Which colours would beharmonious; which ones would becomplementary? One way toinvestigate which colours worktogether is to look at multicolouredflowers (pansy for example) andvariegated foliage (perhaps coleus).Why do the petals of a red tulip appearred in sunlight? What colour would the

««« By Philip Gebhardt and Sandra CooperPhilip Gebhardt teaches evening science courses at the PalmerstonCommunity School in Whitby, Ontario. Sandra Cooper is an educationalassistant at Eagle Ridge Public School in Ajax.

Growing with your Students


SCIENCE IN THE CLASSROOM

This information isrecommended for use with the OntarioCurriculum,

Grades 3, 4, 6, 7 & 8: Life SystemsGrades 3 & 5: Earth and Space


S CIENCE IN THE CLASSROOM

petals appear if the light source weregreen? Your students can design andconduct experiments to predict whatwill happen and then test theirprediction with red tulip petals in thespring. Depending on what coloursyour students’ garden incorporates,you can help them to discover thatwarm colours (red, orange, yellow)appear to come forward while coolcolours (blue, violet, green) recede.

The Bulbs Need a HomeWhen looking at locations, try to findan area that has 4 to 6 hours ofsunlight per day. Bulbs will toleratesome shade, but lots of sunlight willencourage larger flowers and willenable the bulbs to produce and storethe food they will need for successiveyears. Also, blooming will be delayedif the bulbs are in shade. Good soildrainage is important because thebulbs will rot in wet soil. If the soil inyour area does not drain well, you canadd sand to improve drainage. If thearea drains too quickly and doesn’tretain water, you can add materialfrom the school’s compost bin or buysoil amendments (such as peat moss,humus, well-rotted manure, grassclippings, composted leaves, hay,straw or almost any organic material)from a nursery.

The size of the proposed garden willneed to be taken into consideration. Itis wise not to start out too large, asfilling it can not only be daunting, butexpensive.

A garden near the front of the schoolworks well as it becomes a welcomingsight not only for those involved withthe school, but for the community atlarge. Why not let everyone admire thehard work the students do? In addition,locations in the rear of the school maybe subject to unavoidable damagefrom recess play and soccer balls.

Bulbs and Euclid MeetYou may not have much choice whereto put your bulb garden. But if you do,there are many options open to you to

make the garden interesting and tohelp motivate your students. As aclass, discuss what shapes you coulduse. Depending on size and location,you might consider simple square,rectangular, triangular or circularshapes. Beyond that, think aboutcrescents. You might even incorporatevarious geometric shapes within asingle bed. Of course, you could throwcaution to the wind and settle on anirregular or freeform shape. Yourstudents can draw their garden designsto scale on graph paper. After youhave a design, decide whether to plantthe bulbs in rows, to scatter the bulbsor to group the bulbs in clumps.

Individualism Can Be Better –SometimesOnce you’ve made the basic decisionsrelated to the type (or types) of bulbsto plant, the colours to use, where tolocate your garden and the shape ofyour garden, then it’s time to buy thebulbs. You can buy bulbs individuallyor in bags. Either way, choosinghealthy bulbs is key. Bags are lessexpensive, but you can choose a widerrange of colours and varieties if youbuy individual bulbs. By opting to buyindividual bulbs, you can handpicklarge bulbs. Generally, large bulbsmean large flowers. You can alsoinspect individual bulbs. You can feelthe bulbs: hard bulbs are good; softbulbs are not desirable. You want toavoid bulbs which have been damagedor show signs of disease.

Different bulbs flower at differenttimes, so don’t expect a spectaculardisplay of crocus, tulips and daffodilssimultaneously. This is a good reasonfor planting in clumps (at least sevenbulbs per clump). That way you canintersperse different bulbs. When theydo flower, you will have clumpsplaced throughout the garden so nomatter what bulbs are blooming it willlook as if there are flowers everywhere— there will be no obvious bare spots.Even tulips will bloom at differenttimes. There are early season

bloomers, midseason varieties and lateseason types. If you want to extendyour display of blooms, vary theplanting depth of the bulbs. Bulbsplanted deeper will bloom later thanshallow planted bulbs. Varying theplanting depth of the bulbs is anopportunity to discuss variables thataffect the outcome of an experiment.

There are many effective ways tooffset the cost of a bulb garden. Thinkabout having a bulb drive. Ask parentsto donate a bulb, or have the schoolbuy the bulbs and have studentscontribute to help offset the cost. Youmay want to talk to your local nurseryand ask them to donate some bulbs foryour venture. Many nurseries are morethan happy to donate to schoolsbecause it is good advertising for themand it encourages future gardeners.

The When and HowDeciding when to plant the bulbs isstraightforward. It needs to be donebefore the first frost. If you’re not surewhen that is in your area, ask at a localnursery. The real criterion is that thesoil temperature should be below 15°C.

Parents are a great source forgardening tools. Ask if any parents arewilling to lend, or better yet, donatesome old, but useable tools. You willneed 2 or 3 shovels, a garden rake, andsome hand held trowels. Awheelbarrow will make mixing soileasier, but this can be done by placinga garbage bag on the ground andsimply placing the soil on top of it. Awheelbarrow also will help with thecleanup! If you do not have access toan outdoor tap, you will need 2 or 3watering cans.


A bulb cutaway

Growing with your students (...continued from page 19)

Here are 5 easy steps to aperfect bed:

1. Prepare the bed• Dig the bed to a depth of 25 to 30

cm and then thrust your digging forkinto the bottom of the hole to aeratethe bed a bit more.

• Next, return a couple of centimetresof the soil you removed to thebottom of the hole so that the bulbswill rest on loose, free-draining soilwith no air pockets. Mix bulb food(usually a superphosphate) or bonemeal into this soil. These will helpto feed the bulbs and promote rootgrowth. (If you’re up to it, you canreplace these with well rottedmanure.)

• Smooth the bottom surface to makeit level.

2. Firm the bulbs in place• Place the bulbs in the bed in the

design of your choice

• Keep the pointed growing tip (thenose) of the bulb on top and pressthe rounded bottom (the basal plate)into the loose earth.

• Set the bulbs at a depth equal tothree times their diameter. (Fortulips, that’s about 15 cm.)

• Space large bulbs about 15 to 20 cmapart; space small bulbs about 5 to10 cm apart.

• Gently press the bulbs into the soil,so they are in good contact with thesoil and so they will not move whensoil is returned to the bed.

• At this time, you might want to put2 or 3 bulbs on their side andanother few upside down as a test todetermine what happens.

3. Fill in the bed• Shovel the soil in gently at first, so

the bulbs don’t get jostled out ofposition.

• Finish off by mounding the soilslightly above ground level. (It willsink as it settles.)

4. Water• Water to a depth of 25 to 30 cm to

encourage root growth.

5. Mulch• Do not mulch until after the first

major frost. If you mulch too early,the wet mulch will promote bothdisease and rot.

• Mulching helps control weeds andconserves soil moisture. Use leafmold, compost, shredded bark, orother attractive organic materials.The mulch can be 2.5 to 5 cm deep.

the soil to make it more suitable forplants? Then there’s weather. Sincebulbs need to be planted before thefirst frost date in your area, there’sresearch to be done to find out aboutthat. Will you need to water the bulbsso they don’t dry out or will there besufficient rain? Rain means clouds anda study of cloud types. Are therebeneficial insects in your garden orwill you need to deal with pests? Didyour students find worms when theydug up the soil? If not, should youimport some worms? What do wormsdo for a garden anyway? Although thebulbs have enough stored food to carrythem through their first season, theywill eventually need nutrients torestock the bulb for succeeding years.What fertilizers are available? Will youuse chemical fertilizers or organicfertilizers? Read the labels on fertilizercontainers with your students. What’snitrogen? (And why do plants need it?)Hang on, nitrogen is a gas. Shouldn’t itescape when you open the container?What else is in fertilizer? Once youhave investigated the chemical symbolslisted on the package, what othersymbols can your students uncover?

Once you’ve exhausted the scienceand technology possibilities, you canmove on to other subject areas. Mathworks well here. Of course, yourstudents will need to use linearmeasurement to plant their bulbs at anappropriate depth. What’s theperimeter of the garden? What’s itsarea? If your students dig down 30 cmto aerate the soil and break up theclumps, what volume of soil will theyhave worked? Based on the area ofyour bed and the separation betweenbulbs, your students will be able toestimate how many bulbs they willneed. This might be a mathematicalcalculation or on a drawing of the bed.That will lead to cost calculation.Once they know how many bulbs they

S CIENCE IN THE CLASSROOM



Mulching beds

How Did We Do That?Record keeping is an integral part ofany scientific activity. Consider usingphotography to supplement yourrecords. Be sure to photograph thegarden area before you start work. Thatway, you’ll have ‘before’ and ‘after’pictures. Photograph the site and thestudents as work progresses and maybeeven take a shot or two in midwinterwhen the bed is buried in snow.

Linking to Other SubjectsOnce you’re this far, the possibility oflinking bulb planting to other scienceand technology topics and to othersubject areas seems natural. Althoughbulb planting is an easy activity, itlends itself well to extension studies.What soil type do you have in yourschool yard. Is it clay? Is it sandy?Clay soils don’t drain well; sandy soilsdrain too quickly. How can you modify

fermi questions

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