M.C.H.S. Science Skills
Table of Contents

I.  SAFETY IN THE SCIENCE CLASSROOM	2
General Safety Precautions	2
Handling Materials	3
Safety Equipment	4
Other Equipment	4
When an Activity is Completed	5
Care of Laboratory Equipment	5
WHMIS	5
WHMIS Symbols	6
NFPA Coding	6
Labels	7
MSDS Sheets	8
II.  COMMUNICATION	9
Writing Laboratory Reports	9
Writing Research Reports	12
Writing an Essay for Science Courses	13
Writing Bibliographies	15
Oral Presentations	16
III.  LABORATORY SKILLS	17
Lab Equipment	17
Determining Mass	18
Using the Bunsen Burner	21
Constructing Data Tables	22
Graphing	23
Laboratory Drawings	26
IV.  EVALUATION	29
Calculator Policy	29
Guidelines for Significant Digits, Manipulation of Data, and Rounding in the Mathematics and Sciences	30
Writing Exams	31
I.  Multiple Choice Questions	31
II.  Numerical Response Questions	36
III.  Written Response Questions	39

 I.  SAFETY IN THE SCIENCE CLASSROOM

This information is for all students who are enrolled in science at Memorial Composite High School.  In order for students to work safely in the science classroom and laboratory, each student must be aware of and able to follow safety requirements and WHMIS guidelines.

Much of what you do in high school science will involve using equipment and materials and following proper procedures.  The school laboratory is designed, and instructions are given, to ensure that you will have an accident-free environment in which to enjoy science.  Specific activities will have specific safety routines to follow, therefore, the information given here will apply generally to all activities  and laboratory experiments with the specifics given as needed.          

WHMIS  is a national system designed to ensure that information regarding hazardous materials is readily available in the workplace.  Your "workplace" in science is the classroom and laboratory.  You will use this information along with safety guidelines to complete activities and laboratory work safely.

General Safety Precautions

1. 	Work carefully, following given procedures and safety guidelines.

2.  	Tie back loose hair, roll back and secure loose sleeves.  Wear shoes 	that cover your feet as much as possible.  Avoid wearing baggy 	clothing, jewelry or things that could catch on and knock down 	equipment.  Wear safety glasses at all times in the lab.

3. 	Try not to wear contact lenses during experiments using chemicals.
 
4.  	Never eat or drink in the laboratory, or keep food or drinks in the 	laboratory.

5.  	Never perform activities that are not authorized by your teacher.  Do 	not try to perform experiments at home.  You may be hurt if you try 	to do them without appropriate supervision.  

Before Beginning an Activity

1.  	Read through, or thoroughly plan the entire activity so that you are 	sure of what to do.  Complete all pre-lab work.

2.  	Make sure the work area is clean before you start.

3. 	Clear all books (except your notebook) from the work area.

4.  	Make yourself familiar with safety precautions and applicable 	chemical data information before handling materials.

5.  	Do not begin an activity until you are instructed to do so.

Handling Materials

1.	Use only the quantities of materials indicated in the instructions.

2.  	Never touch or taste any material unless you are told to do so.

3.  	When you are instructed to smell a chemical in the laboratory, do not 	place it close to your nose.  Instead, use you your hand to move the 	air from the sample close to your nose in order to smell the chemical.

4.	Avoid contamination of chemicals.  This normally occurs during 	transfer from one container to another. 

5.	Return chemicals and materials to their proper storage area.  DO NOT 	return any chemicals to their original containers. 

6.  	When pouring liquids into a test tube, place the test tube in a rack.  	Never pour liquids while holding the containers close to your face.

7.  	If any part of your body comes in contact with any harmful chemical 	or specimen, wash the area immediately and thoroughly with water.  	If your eyes are affected, do not touch them but wash them with 	water immediately and continuously for at least ten minutes.

8.  	Wash your hands after you handle chemicals.

9.  	Clean up any spilled chemicals immediately, as instructed by your 	teacher.  Place waste materials in waste containers as indicated.

10.	Particular attention should be given to the handling of corrosive 	liquids such as acids and bases.  Always transfer acids or bases INTO 	water while stirring.

Safety Equipment

1.  	Listen carefully to your teacher's instructions on when and how to 	use the safety equipment:  safety glasses, fire extinguishers, eye-	washing station and fire blankets.  Find out the location of all safety 	equipment in the laboratory.

2.  	Make sure you know how to exit the classroom in case of fire.  Know 	where the nearest fire alarm is. 

3.	Report all accidents to your teacher immediately.

4.	Safety goggles or glasses must be worn when working with 	chemicals.

5. 	Laboratory aprons or coats should be worn whenever working with 	chemicals or heated substances.

Other Equipment

1.  	Never force  glass tubing or a thermometer into a dry stopper.  	The hole in the stopper should always be lubricated with soapy 	water or glycerine.

2.  	Never use cracked or broken glassware.  If glass does break when 	you are using it, follow your teacher's instructions on how to clean it 	up.  Do not put broken glassware in the garbage.
		
3.  	Watch for sharp or jagged edges on equipment.

4.  	Report all accidents, regardless of how minor, to your teacher.  As 	well, report any damaged or defective equipment.

5.  	After each experiment, clean all equipment and put it in its proper 	place.  Do not leave equipment that you are not using lying around 	the work area. 

When an Activity is Completed

1.  	Finish your work with ample time left to complete your clean-up.

2.	Wash glass apparatus with soap, water and a brush.  Rinse and put it 	away, or leave it to dry on the rack.

3.	Properly put away all materials and equipment.

4.	Wash or wipe countertops, throw garbage into containers, and clean 	the sink.

Care of Laboratory Equipment

1.  	Use laboratory equipment for its intended purpose ONLY.

2.	Be cautious - lab equipment is expensive.  Report any breakage to 	your teacher immediately.  There is a special box for disposal of 	broken glassware - use it!

3.	Clean all lab equipment thoroughly after using it.  This involves 	washing it out,  drying it well, and either putting it away or leaving it 	to drain on the rack.

4.	Store all equipment as directed by your teacher.

5.	Wipe lab benches off after each lab exercise.  Thoroughly clean your 	work area before you leave the lab.

6.	Put your chair up when you leave the lab.
 
WHMIS

WHMIS is a hazardous product information program that is in effect in workplaces, schools, universities and any other setting in Canada that has and uses hazardous materials.   The purpose of this program is to make sure that everyone has the information needed to work safely.  

WHMIS Symbols

						(graphic)

NFPA Coding

						  (graphic)

WHMIS has three components:

			1.  Labels
			2.  Material Safety Data Sheets
			3.  Worker (that means you!) Education

Labels

All potentially hazardous materials are labelled to give you basic information about the product safety.  The labels can be recognized right away by their distinctive slashed marked borders.  

						(graphic)  

MSDS Sheets

If you need to find out more about the product than you can find on the label, you can go to the MSDS.  These sheets have more detailed information than the labels.

					(graphic)

II.  COMMUNICATION

Writing Laboratory Reports

Communication is a very important part of science.  Scientific discoveries are useful only when others know about them:  in the world of science, the means by which new discoveries are shared is the laboratory report.  In it, scientists follow a standard format designed to clearly and efficiently relate their findings to their peers.  The general format that we would like you to follow in reporting your findings in the laboratory is described below; your teacher may modify it depending upon the laboratory activity you are doing.

1.  Problem

This should be expressed as a question, preferably only one sentence long.  The format should be "How does 					 affect 
					        (the manipulated variable)
				?
(the responding variable)

2.  Background Information

Explain any theory or terms that must be understood in order to carry out the laboratory exercise.

3.  Variables

Manipulated - The condition that you, the experimenter, have changed.
Responding - The effect that you have measured.
Controlled - Variables or conditions that have to be kept the same throughout the experiment, or they could have an effect on the results, too.

4.  Prediction

A description of what you expect the outcome of the laboratory exercise to be. 

5.  Hypothesis

This should be a tentative answer to the question asked in the problem, along with a reason or explanation of why you expect to see these results.  It must be testable.

6.  Materials and Equipment

Make a list of everything that you will need in order to solve this problem.  Be sure to include the amounts of each substance or material that you use, and the brand and model of any major pieces of equipment used.  A point-form list is acceptable here, as is a reference to a materials list given in a lab manual.

7.  Procedure

The procedures section of your lab report should include a step-by-step list of everything that you are to do in the lab.  Number each step, and write only one instruction per step.  The procedure is probably best written in chronological order, and may be written in point form if you wish.  Strive to make this section so clear and easy-to-follow that anyone in the class could repeat the experiment merely by reading your "Procedure" section.  Be sure to include any safety precautions specific to the lab exercise in this section.  As well, you may wish to put diagrams in this section (for the sake of clarity).

8.  Results/Evidence

This section of your lab report should describe what you saw in your lab exercise.  All observations, measurements, and estimates should be placed in this section.

9.  Analysis

In this section, the results gathered are processed in a manner that will help you to reach some conclusions about the relationship between the manipulated and the responding variable.  Graphs, averages, and sample calculations should appear here.  As well, you should explain your data.  What relationship did you find between your manipulated and responding variables?  What does this mean?  Explain whether your findings support or refute your original hypothesis.

11.  Evaluation

Evaluate the experimental design.  Did the experiment show what it was supposed to show?  Were there errors in the experimental design or in the way in which the experiment was carried out?  How significant were they (i.e. how much did they influence the outcome of the experiment)?  

12.  Conclusion

This section should be a one sentence summary explaining the relationship between the manipulated variable and the responding variable, as determined in your experiment.

13.  Questions

Answer all assigned questions in this section of the lab report.

14.  References

This is a list of any sources of information used in carrying out or analyzing the results of your experiment.  Format to be followed is:
"Author's Name, Title of Source, where published, year published.  Pages used in your report."

Use material from your textbook or lab manual as the basis for your lab report.  Remember, however, that you are not writing for yourself - you are trying to communicate ideas to others.  For this reason, you need to be especially careful about neatness, spelling, and sentence structure - all of which contribute to clarity of expression.  The writing of a laboratory report is different than most other types of writing, but it is a skill that is indispensable to a good scientist.  By following the plan outlined above, you should be able to produce excellent results every time!

Writing Research Reports

Stage 1:  Planning

	• establish your topic:  develop topic statement, subtopics, and 	subject headings
	• identify information sources
	• identify your audience
	• identify the format that your presentation is to take

Stage 2:  Information Retrieval

	• locate resources
	• collect resources
	• notetaking:
		• read a passage until you understand it.  Seek out help, if 		necessary.
		• look up unfamiliar words in the dictionary
		• jot down key words and phrases only
		• write enough information so that it makes sense two weeks 		later
		• use quotations, paraphrases, summaries
		• check the notes against the original to see that all the 			author's ideas are included and are correct
		• be sure to cite the source of information used properly (see 		the "Bibliography" page below for details)

Stage 3:  Information Processing

	• choose relevant information
	• evaluate the information
	• organize and record the information
	• make connections and inferences
	• create a product
	•  DO NOT PLAGIARIZE!!!
	• revise and edit

Stage 4:  Evaluation

	• evaluate your product
	• evaluate your research procedures and skills

Writing an Essay for Science Courses
(Adapted from S. Nisbet and B. Knoll, E.P.S.B. No. 7)

I.  Outline  
(NOTE:  Spend five minutes MAXIMUM! making your outline on an exam.)

	• jot points in margin of paper
	• must include:  Thesis (see II.A.1 below), Reason One + Example(s), 	Reason Two + Example(s), Reason Three + Example(s)
	• other information - included if time permits

II.  Structure

	A.  Introductory Paragraph

		1.  State your thesis (opinion/point/topic; follow it with your 		main idea)
			Example:  Essay topic:  “Why is water an important 				medium for life?”  Main idea:  polar structure

		2.  List your supporting ideas
			Example:  Why is polarity important?  Because it leads to 			adhesion, cohesion, etc.

	B.  Developmental Paragraphs
		• three (minimum) to five reasons: each reason developed in 		its own paragraph

		1.  Reason One
			a.  must support main idea or thesis
			b.  explain how the reason supports the thesis
			c.  provide two specific examples/diagram(s)/quote(s)/ 			illustration(s).  Include one example from an “expert”, 			and one example of your own.

		2.  Reason Two, Three, etc.
			• each reason is presented in a new paragraph, using the 			above format.

	C.  Conclusion
		• restate your ideas in a new paragraph
		• summarize your essay:  “wrap it up”
		• never introduce new information here

III.  Format

	A.  Tone:  semi-formal, third person.

	B.  Diagrams, if included, should be 1/3 page in size, titled, drawn in 	pencil and labelled in ink, and cited in the essay where appropriate 	(i.e. “refer to Diagram A”).

	C.  Best possible handwriting!

	D.  Must flow together - use transition statements.

	E.  Be sure to compare and contrast ideas.

	F.  ALWAYS LINK WHAT HAPPENS TO WHY IT HAPPENS.

Writing Bibliographies

List all of the sources of information that you used in writing your report.  This section should be the last page of your report.  Type the title so that it is centered and is located one inch from the top of the sheet; do not underline the title.  Double space between the title and the first entry, and continue to double space for the entire page.  Begin each entry at the left margin and indent each subsequent line of the same entry one half an inch from the left margin.  This makes each entry "stick out" clearly for the reader.  Arrange your list of works cited alphabetically, according to the author's last name, or if his/her name is unknown, by the first word in the title (other than "A", "An", or "The").

In citing books, arrange the information in the following order:

	1.  Author's name.  For the principle author, write their last name 	first; for all subsequent authors, their last name should be written 	last.
	2.  Title of the book.
	3.  Name of the editor, translator, or compiler.
	4.  Edition used.
	5.  Number(s) of volume(s) used.
	6.  Name of the series.
	7.  Place of publication, name of publisher, date of publication.
	8.  Page numbers used.

For examples, and for information on how to cite various other media, please refer to the following work found in the reference section of the library:

Gibaldi, Joseph, and Walter S. Achtert.  MLA Handbook for Writers of 	Research Papers.  3rd ed.  New York:  Modern Language Association 	of America, 1988.  88-97.

Oral Presentations

Helpful Hints:

	• DON’T READ YOUR REPORT!
	• Plan what you are going to say.  Get familiar with your 	presentation:  practice it!
	• If you must read notes, only write down key points - not the entire 	presentation.
	• The presentation must suit your audience.

Organizing Your Presentation:

	I.  Introduction

		• tell your audience what you are going to tell them
		• excite them - capture their interest and attention!

	II.  Body of Your Presentation

		• tell them.  Start with your best and most interesting point in 		order to hook your audience.
		• make it memorable.  Explain how the topic might be of 		benefit to them, restate your key points to help your audience 		remember them, link the information to things that your 		audience is already likely to know about.
		• keep your presentation short, simple, strong, and sincere.

	III.  Conclusion

		• tell them what you just told them.  Wrap it up in a neat 		package.
		• HAVE A BIG FINISH!

III.  LABORATORY SKILLS

Lab Equipment

Determining Mass

A.  Using the Triple-Beam Balance

1.  How it Works

In order to use the triple-beam balance, the object whose mass is to be determined must be placed on the balance pan (see the diagram below).  The balance pan is counterbalanced by the riders, and the riders have been calibrated against the standard kilogram, so their masses are known accurately.  The influence of gravity is canceled out, because gravity effects both the object to be measured and the riders equally, therefore, only the mass of the object is determined.

2.  Precautions

NEVER

	• carry the triple-beam balance by the beams or by the zero 	balance arm - both of these parts can be bent by pressure.  Once 	bent the balance cannot be fixed, and it will cost you about $200 to 	purchase a new triple-beam balance for the school.

	• place hot objects on the balance pan.

	• place chemicals directly on the balance pan.  Always place solid 	chemicals on a piece of clean paper, a watch glass, or in a beaker 	before determining their mass.  Liquid chemicals should be placed in 	a beaker or flask before determining their mass.

ALWAYS

	• carry the triple-beam balance by the base only.

	• make sure that the balance pan is clean before you start.  If the 	balance pan is dirty, wipe it off with a moist paper towel and then 	dry it before use. 

3.  Positioning the Triple-Beam Balance

	a.  Set the triple-beam balance on a perfectly level surface.
	b.  Set all three of the sliding masses to the zero point at the far left 	of the beam.  The two larger masses fit exactly into notches on the 	beams; make sure that they are set accurately into these notches.
	c.  If the line on the pointer (found on the right-hand end of the 	beam) is not aligned with the zero balance mark on the zero balance 	arm, the triple-beam balance will have to be zero-balanced (see 	"Zero-Balancing" below).  If the line on the pointer is lined up with 	the zero balance mark, you may determine the object's mass (see 	"Determining the Mass of an Object on the Triple-Beam Balance" 	below).

4.  Zero-Balancing

	a.  Set all of the riders to the zero position.
	b.  Turn the zero balance screw either clockwise or counter-	clockwise, until the line on the pointer lines up exactly with the zero 	balance mark.
	c.  If this does not work, ask your teacher for assistance.

5.  Determining the Mass of an Object on the Triple-Beam Balance

	a.  Place the object in the centre of the balance pan.  If you are 	determining the mass of a chemical, make sure that it is either on a 	clean piece of paper or a watch glass (solid) or in a beaker or a flask 	(liquid) before placing it on the balance pan.
	b.  Start with the largest rider.  Slide the rider until it just 	overbalances the mass of the object, then place it one notch to the 	left, so that it underbalances the object.
	c.  Repeat this procedure with the second rider.
	d.  After ensuring that both of the larger riders are accurately set 	into notches (most errors in using the triple-beam balance are a 	result of not setting the two larger riders exactly into the notches on 	their beams), slide the smallest rider until it exactly balances the 	object.  The line on the pointer at the right-hand end of the beam 	should line up exactly with the zero balance mark on the zero 	balance arm.
	e.  The mass of the object is the sum of the readings shown by the 	positions of the three riders.  You simply add the numbers together.  	Be sure that your result is shown to 1/100 of a gram.
	f.  After carefully writing down your result, slide the riders back to 	the zero marks and clean up.  Return your materials as indicated by 	your teacher.

B.  Using the Electronic Balance

	1.  Make sure that the balance pan is clean.  If not, clean it.
	2.  Plug in the electronic balance.
	3.  Turn on the electronic balance.
	4.  The display should read 0.0 g.  If it does not, press “Tare”.  If it 	still does not read 0.0 g, then notify your instructor.
	5.  Put either a piece of paper or a container such as a beaker on the 	balance pan.  Tare the balance (tell it to ignore the mass of the paper 	or container) by pressing the "tare" button.
	6.  Add the substance for which you wish to determine the mass.  	Use a scoopula or dropper to help adjust the mass until it is just 	right.  Remember to discard excess reagent; DO NOT put it back into 	the original container!
	7.  Clean the balance.  Turn it off if you are the last person to use it.

Using the Bunsen Burner

Many activities in science require heat.  A common source of heat energy in the science laboratory is the Bunsen burner.

Operating the Bunsen Burner

1.  Natural gas enters the burner through the gas inlet, located just above the base of the burner.  Natural gas is supplied from an adjustable gas outlet on the laboratory bench.  The amount of gas entering the burner can be controlled by adjusting the needle valve, located in the base of the burner.

2.  Air inlets at the bottom of the barrel are used to control the quantity of air being mixed with the gas.  Close the air inlets completely.

CAUTION:  Do NOT lean over the barrel of the burner.  Keep all loose clothing and hair away from the burner.

3.  Adjust the needle valve so that it is open one complete turn.

4.  Hold the striker or match about 3 cm above the barrel.  Turn on the gas at the gas outlet (open fully), and light the burner.

5.  Adjust the air inlets until you can see that both an inner bright blue and an outer dark blue cone have been formed.

CAUTION:  If the burner does not light, turn off the gas immediately, since the unburned gas is flammable.  Determine the source of the problem (ask for help if necessary!) and start again.

Constructing Data Tables

Data is the plural of the Latin word datum, which is translated as "an individual fact, statistic, or piece of information" (Random House College Dictionary).  In science, you will be measuring data throughout the year, and it is important for you to know how to present your data properly.  In order to do this, you will be constructing data tables.  

A data table is an enclosed table that holds your experimental results or measurements.  When constructing a data table, be sure to use a ruler at all times in order to draw lines that enclose your results or measurements.  The title for your data table should clearly describe the contents of the data table, and each column in your data table should be labelled with the name of the variable listed in that column, as well as the units of measure for that variable.  The data table below illustrates the rules for proper construction of a data table.

Table 1:

The Relationship Between Education Level (in years) and Average Income (in Canadian dollars) for Canadian Males, 1988 

Education Level
(yrs.)	Average Income
($)	
<7	26 648	
7-11	30 343	
12-13	32 070	
College Diploma	34 353	
University Degree	46 034	

Graphing

Graphing comes from the Greek word graphos , which means "something drawn or written" (Random House College Dictionary).  Scientists use graphs as a means of studying and expressing the relationship between the manipulated and responding variable.

There are three main types of graphs used by scientists:  line graphs, bar graphs, and pie or circle graphs.  An example of each is shown below.

Example 1-Line Graph

Example 2-Bar Graph

Example 3-Circle or Pie Graph

Rules to Follow When Constructing a Line Graph:

1.  On the horizontal axis, place the name of the manipulated variable, and its unit of measure.  In example 1 above, the manipulated variable is the Amount of Schooling in years (yrs.).

2.  On the vertical axis, place the name of the responding variable, and its unit of measure.  In example 1 above, the responding variable is the Average Annual Salary in dollars ($).

3.  Calculate the values for the scales so that the plotted data extends over most of the graph (at least 2/3 of the grid area).  All of the plotted points must fit on the graph paper.  

4.  The scales need not be the same along both axes.

5.  In most cases, the manipulated variable scale should start at zero.  However, this may not always be convenient:  use your own judgment.  The responding variable scale must always start at zero:  NO EXCEPTIONS!

6.  The number pairs are plotted as a point (or dot) and the point is circled.  The circle represents your possible error in calculating the location of that point.

7.  The circles (not necessarily the points)  are joined by a smooth curve.  (A straight line is considered to be a smooth curve.)

8.  If you are plotting two or more lines on a graph, a legend should be placed in the lower right-hand corner of the graph.  The legend should identify each of the lines on the graph.

9.  Your name, class, and the date are written in the top right-hand corner of the page.

10.  The title of the graph is written across the top of the page.  The title should be centered, and should be written as "The manipulated variable versus the responding variable" (i.e. the title should indicate the relationship between the manipulated and responding variables).

Laboratory Drawings

Drawings made during laboratory work should conform to the following format:

1.  The drawing should be on white, unlined paper using only a pencil.

2.  In the top, right-hand corner of the page, your name, class, and the date should be shown.

3.  Centered at the top of the page, the title of the drawing should be written.  After the title, the magnification at which the organism was drawn should be written in brackets.

4.  The drawing should be at least one-half of a page in size and slightly to the left of centre on your page.  Draw only what you see.

5.  If there are too many cells visible on the slide, select one or two as a representative sample - do not attempt to draw them all.

6.  There should be no shading or coloring:  if a distinction needs to be made between structures, then stippling should be used.

7.  All structures drawn should be labelled.

8.  Lines from the object being labelled to the label should be drawn horizontally and with a ruler.  Arrowheads should not be used.

9.  Labels should be on the right side of the paper, in a vertical list.  The first letters in each label should be aligned vertically on your page.

10.  All labels should be printed in small case letters, unless the name is a proper noun.

11.  Structures not seen but known to be present can be included in the drawing, but their labels should be bracketed.

12.  Indicate the scale of your diagram under your drawing, on the left-hand side.

13.  A brief description of the appearance of the specimen should be included under the drawing.
Below is an example of what your laboratory drawings should look like:

The size of an object visible under a microscope lens can be determined using the following procedure:

IV.  EVALUATION

Calculator Policy

Guidelines for Significant Digits, Manipulation of Data, and Rounding in the Mathematics and Sciences

Writing Exams
(adapted from Barron's Guide to Writing the Advanced Placement Exam in Biology, 1988)

I.  Multiple Choice Questions

Multiple choice questions are called "objective" questions because the test writer's opinion is not asked for.  Everyone taking the exam is expected to select the correct answer for each test item from the choices given.  There is only one correct answer; there are no allowances for individual differences or individual bias.  The answer that you choose is usually indicated by your blackening the appropriate space on the answer sheet.

Although they may appear to be easy, multiple choice questions often are difficult.  You, the test taker, have limits set both in time and in content.  Often you will be allocated less than one minute per question.  Therefore, you must be a thorough and a rapid reader, and you must know the facts of science.

As well, you must develop the skills of test taking in order to be successful in science.  These skills are not acquired overnight, but must be developed day by day.  In order to do well on a multiple choice exam, you will have to:

	1.  Read proficiently - thoroughly, accurately, and quickly.
	2.  Become very familiar with science terms.
	3.  Understand and obtain meaning from the questions.
	4.  Have the facts of science at your fingertips.
	5.  Use facts in problem-solving situations.
	6.  Use facts to make generalizations.
	7.  Be flexible in your thinking.
	8.  Be able to think of the broad principles involved.
	9.  Use mathematics to solve problems.

The only way you can become skillful in answering multiple choice questions is by consistent hard work.  You must read your assignments with care and with interest.  The work that you do in the laboratory will also contribute to your learning.  The notes that you take must be useful for study.

Let us now look at some multiple choice questions in order to determine the best way to answer them.  As you go through this section, be sure to keep these guidelines in mind:

	• Read thoroughly, quickly, and accurately.
	• Know the facts of science.
	• Select the BEST choice.

A.  Questions of Fact

1.  When a lysosome combines with a vacuole that contains complex organic molecules, which function is initiated?
	a.  cell division
	b.  protein synthesis
	c.  cellular digestion *
	d.  cellular respiration

2.  Which substance is not transported across cellular membranes by active transport?
	a.  potassium ions
	b.  sodium ions
	c.  glucose
	d.  water *

The multiple choice questions thus far presented are to encourage speed in reading and answering.  Note that these questions to test your knowledge of scientific facts are deliberately written with short stems, and with choices that are limited to one or two words, or very short phrases.  Questions of this type are dispersed throughout the test, allowing the test taker a "breather", or mental relaxation, between questions that require thought or problem solving.  But don't be fooled by short questions:  you must have the facts at your command in order to answer these questions correctly in as short a time as possible.

Some students make the mistake of believing that they can understand science without memorizing certain basic facts.  Actually, you must have a thorough background in science in order to score well on an examination.  If you have to puzzle over each of the short fact questions, you will lose valuable time, indicating that you do not have the facts at your command; you also will be at a loss in problem solving and in answering questions of practical application.

B. Questions of Judgment

The approaches to multiple choice questions differ.  Some questions require fast recall in order to make a comparison or judgment.  Other questions that are more lengthy and involved demand more reading.  However, while you are getting the sense of such a question, you must think through the choices offered and then make a selection of the one correct answer.  Some of the key words or phrases used in judgment questions serve as qualifiers:  how much, which, which is greater than, which is less than, which includes the other, to what extent, all of the following except.  Familiarize yourself with this type of question.  You must be flexible in thought and sharp in getting meaning quickly.

Study the questions that follow.

3.  Lipid-soluble substances tend to move across cell membranes more easily than those substances that are not lipid soluble.  The reason is that
	a.  lipids are small molecules.
	b.  nonlipid substances are large in size.
	c.  lipids make up the basic structure of cell membranes. *
	d.  ATP is expended only in the movement of lipid-soluble 	substances.

4.  The duodenum is capable of secreting several substances including the hormone cholecystokinin (CCK).  Among other things, CCK stimulates the gallbladder to contract, which forces bile into the duodenum.  Given this information, it would be logical to predict that
	a.  CCK is capable of digesting lipids.
	b.  bile is needed to prevent the accumulation of CCK.
	c.  removing the gallbladder will inhibit the manufacture of CCK.
	d.  the stimulus for CCK release is the arrival of lipids in the 	duodenum. *

C.  Questions Requiring the Interpretation of Data

Interpretation questions are those that present a set of facts or a series of conditions in a number of ways:  written information, tables, or diagrams.  From the facts or experimental conditions given, you are called upon to demonstrate an ability to understand the meaning of the material.

Questions of interpretation have certain characteristics.  They usually deal with experimental data and are based upon basic scientific facts.  The data are set out in any of the ways mentioned above.  The presentation of the data is necessarily more lengthy than the usual multiple choice question.  Using the data, you are to answer several multiple choice questions that require knowledge of a given area of science.  In addition, these questions test your ability to draw correct conclusions based upon scientific facts and experimental data.

Let's analyze some such questions.

Use the following information to answer questions 4 and 5.

A young mountain climber from Calgary was chosen at the last minute to fill in for one of the junior members of a Mount Everest climbing expedition.  She flew directly from Calgary to Nepal.  Upon her arrival, she was escorted to a high-altitude supply camp where she was to help prepare for the ascent of the mountain.  Shortly after beginning this work, which involved strenuous activity, the young mountain climber collapsed.  After recovering, she started working at a much slower rate.  For the rest of her month-long stay at the supply camp, the mountain climber gradually increased her workload until she was able to function normally at that elevation.

5.  Assuming that the young mountain climber was in excellent health when she left Calgary, which condition likely caused her collapse?
	a.  A high leukocyte count.
	b.  High levels of oxyhemoglobin.
	c.  An inadequate erythrocyte count. *
	d.  Inadequate levels of carbaminohemoglobin.

6.  Upon returning to Calgary, a major physiological difference the mountain climber will notice is a temporary decrease in her
	a.  parasympathetic nervous activity
	b.  blood’s ability to carry oxygen
	c.  breathing rate *
	d.  energy level

Use the following information to answer question 7.

Results of Analyses of Food Mixtures

Food
Mixture	
Biuret Test	
Iodine Test	Benedict’s Test	Sudan IV Test	
I	violet	yellow-brown	blue	dissolved	
II	light blue	black	orange	undissolved	
III	violet	yellow-brown	blue	undissolved	
IV	light blue	black	orange	dissolved	

7.  Which food mixture contains proteins and lipids but lacks reducing sugars?
	a.   I *
	b.  II
	c.  III
	d.  IV

II.  Numerical Response Questions
III.  Written Response Questions