PREPARE FOR LABORATORY WORK

1
PREPARE FOR LABORATORY WORK

• Never perform unauthorized experiments.
• Know how to use the safety shower, eye wash,
  fire blanket and first aid kit bucket of sand.
• Do not work in the lab without your teacher in
  the room.

2
DRESS FOR LABORATORY WORK

• Tie back long hair.
• Do not wear loose sleeves as they tend to get in
  the way.
• Do not wear open shoes on a lab day.
• Wear lab aprons during all laboratory sessions.
• Wear safety goggles during all laboratory
  sessions

3
BUNSEN BURNER SAFETY

• A Bunsen burner flame is very hot. The center of
  the flame will be over 1000 degrees Celsius.
  Treat burner flames with respect.
• Always use the main gas shut off valve on the
  desk to shut off a Bunsen burner.
• The valve at the base of the burner is only used
  to control the flame.

4
BUNSEN BURNER SAFETY

• If your hair or clothing catches on fire stop
  drop and roll.
• If someone else's hair or clothing catches on
  fire, wrap them with a fire blanket to smother
  the fire. Do not let them run.

5
AVOID HAZARDS

• Use caution when handling hot glassware.
• When diluting acid, always add acid slowly to
  water. Never add water to acid.
• Keep caps on reagent bottles. Never switch caps.

6
ANIMAL SAFETY

• Do not cause pain, discomfort , or injury to an
  animal.
• Wash hands after handling animals

7
SAFETY WITH CHEMICALS AND DISSECTING SPECIMENS

• Do not touch or taste any chemical unless
  specifically instructed to do so.
• Read chemical labels more than once before using
  the contents - it is easy to confuse chemicals.
• When working with chemicals or dissections, keep
  your hands away from your face. The skin on your
  face is much more sensitive to irritation than
  your hands.

8
SAFETY WITH CHEMICALS AND DISSECTING SPECIMENS

• To smell something, hold it away from your nose
  and wave your hand over it towards your nose.
  This is called wafting. You may pass out or
  inhale dangerous gases is you just stick your
  nose over the container and breathe in.
• Flush any chemical spill on your skin with plenty
  of water. The rule of thumb is 15 minutes.

9
SAFETY WITH CHEMICALS AND DISSECTING SPECIMENS

• When heating anything in a test tube, point the
  mouth of the test tube towards a wall, away from
  people.
• Do not lay the glass stopper from a reagent
  bottle on the lab table. Hold the handle of the
  stopper between two fingers while you pour from
  the bottle.
• When mixing acids and water, pour the acid into
  the water. Remember, AnW (root beer)
• Wash your hands when you are finished with the
  lab.

10
SAFETY WITH GLASSWARE BROKEN GLASS

• Never use chipped or broken glass. If you notice
  chipped or cracked glassware during a lab please
  report it to the instructor to be replaced.
• Broken glass should never be handled with your
  hands. Use a dustpan and broom to sweep up broken
  glass. Small pieces can be wiped up using a wet
  paper towel.
• Broken glass should be placed in the proper
  container - either a can for broken glass or a
  sharps container.

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SAFETY WITH GLASSWARE BROKEN GLASS

• Always have the instructor clean up a broken
  mercury thermometer. Mercury is a poisonous
  substance and should not be handled.
• Broken glass that has contacted blood must be
  disposed of in a sharps container.
• The plastic cylinder guard on a graduated
  cylinder is to protect the cylinder from breaking
  if it should tip over. The cylinder guard is not
  made to slide up and down for measuring.

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SAFETY WITH GLASSWARE BROKEN GLASS

• A graduated cylinder should be laid down when it
  is empty - if it is laying down it can't be
  tipped over.
• Remove glass tubing and funnels from stoppers as
  soon as your lab is finished. If you do not they
  will become stuck in the stopper.

13
BLOODBOURNE PATHOGEN SAFETY

• Wear latex gloves anytime you assist someone who
  is or has been bleeding or vomiting.
• Clean the entire area (desktop, floor, etc.) with
  a disinfectant when you are finished caring for
  the person.
• Remove your latex gloves by pulling them off
  inside out. Avoid contact with the outside of the
  gloves.

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BLOODBOURNE PATHOGEN SAFETY

• All paper towels, tissues, latex gloves and other
  materials used to clean up blood and other
  possible infectious materials should be disposed
  of in the proper biohazardous waste bag.
• Standard Biohazardous waste bags are red with the
  biohazardous waste symbol on them. If one is not
  available, use a regular plastic garbage bag and
  attach a biohazardous waste sticker to the bag.
• Wash your hands thoroughly with a disinfectant
  when you are finished.

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CLEAN UP

• Consult teacher for proper disposal of chemicals.
• Wash hands thoroughly, following experiments.

16
IN CASE OF ACCIDENT

• Report all accidents and spills immediately.
• Place broken glass in designated containers.
• Wash all chemicals from your skin immediately
  with plenty of running water.
• If chemicals get in your eyes, wash them for at
  least 15 minutes in an eyewash.

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• Were you to cut your finger while working in the
  lab you should ______.
• not worry about it if it is not bleeding too much
• wrap a wet paper towel around the cut and
  continue working
• seek medical aid from a qualified person
• go the first-aid kit yourself and place
  antiseptic on it

Answer C
18

• Safety items such as goggles, tongs, heat
  insulated mittens, aprons, and rubber gloves
  should be used at ALL times while in the
  laboratory.
• True
• False

Answer B
19

• Which is the correct way to hold a test tube
  while heating its contents? A. Pointing
  straight up. B. Pointing horizontally. C.
  Pointing away from yourself and others. D.
  Pointing straight at yourself.

Answer C
20

• Why is it important to NOT run if your hair or
  clothing catches fire in a science lab? A. It
  will cause others to run. B. Running will put
  out the fire. C. The fire will burn out on
  its own. D. Running will feed oxygen to the
  fire.

Answer D
21

• MSDS is a short way of saying A. Multiple
  standards data sheets. B. Material safety data
  sheets. C. Middle school deterioration status.
  D. Mastering school district safety.

Answer B
22

• Laboratory aprons or coats should be worn when
  working with A. glassware of any kind. B.
  small animals when being handled. C. electrical
  equipment. D. chemicals and heated substances.

Answer D
23

• Many chemicals are toxic. The best way to smell
  chemicals safely is to A. bring the container
  to your nose. B. inhale fumes directly from the
  container. C. ask your partner to smell the
  chemical. D. gently wave your hand over the
  container.

Answer D
24
Science Equipment and Taking Measurements
25
Quantity Instrument Units
Mass Balance Grams
Volume Graduated Cylinder Milliliters
Length Ruler Centimeters
Temperature Thermometer Degrees Celsius
Time Stopwatch Seconds
26
Triple beam Balance measures mass
Thermometer measures temperature
Graduated Cylinder measures volume
Stopwatch measures time
Meter stick measures length
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Reagent Bottle
Florence Flask
Erlenmeyer Flask
Test Tube Rack
Test Tube Clamp / Holder
Test Tube
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Watch Glass
Bunsen Burner
Alcohol Burner
Evaporating Dish
Petri Dish
Microscope
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The Meniscus

• When water is placed in a glass or plastic
  container the surface takes on a curved shape.
• This curve is known as a meniscus. Volumetric
  glassware is calibrated such that reading the
  bottom of the meniscus, when it is viewed at eye
  level, will give accurate results.
• Viewing the meniscus at any other angle will give
  inaccurate results.

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Erlenmeyer Flasks and Beakers

• Erlenmeyer flasks and beakers are used for
  mixing, transporting, and reacting, but not for
  accurate measurements. The volumes stamped on the
  sides are approximate and accurate to within
  about 5.

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Erlenmeyer Flasks and Beakers
33
Graduated Cylinders

• Graduated cylinders are useful for measuring
  liquid volumes to within about 1. They are for
  general purpose use, but not for quantitative
  analysis. If greater accuracy is needed, use a
  pipet or volumetric flask.

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Graduated Cylinders
35
Water Displacement Method

• To determine the volume of a regularly shaped
  solid, the formulas from mathematics can be used.
• To determine the volume of an irregularly shaped
  solid, the water displacement method is typically
  used.
• A known amount of water is placed in a graduated
  cylinder.
• The irregularly shaped solid is placed in the
  water.
• The new volume is read.
• The volume of the irregularly shaped object is
  the difference between the two readings.

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Balances

• Mass is the amount of matter in an object. There
  are different kinds of balances used to measure
  mass. Be sure you understand how your balance
  works. Some balances give a single reading.
  Others give two or more readings that you have to
  add together.

37
Balances

• For example, look at the triple-beam balance on
  the next slide. Notice that the middle beam
  measures the largest amounts. To read the mass of
  an object, find and record the masses shown on
  each of the beams. Then add the readings.

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• 200g 70g 6.5g 276.5g

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Metric Conversions
Kilo 1000 k 1000 times
Unit one one
deci 0.1 d One tenth
centi 0.01 c One one hundredth
milli 0.001 m One one thousandth
40
Graduated Cylinders
What is the volume?
About 36.3 ml (dont forget to read from the
bottom of the meniscus and to estimate a digit.
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Triple Beam Balance
What is the mass?
356 g
42
Ruler
What is the length of the nail?
4.08 cm
43
Thermometer
What is the temperature?
47o C
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The volume of the object is_________. A   8
mL B   11 mL C   16 mL D   21 mL E   27 mL
Answer B
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• A student needs to measure exactly 42.5 mL of an
  acid. Which of the following pieces of laboratory
  equipment would it be best for her to use?
• 10-mL graduated cylinder
• 50-mL beaker
• 50-mL graduated cylinder
• 250-mL flask

Answer C
46
Parts of an Experiment and the Scientific Method
47
Scientific Method

• The scientific method is a systematic procedure
  for solving problems and exploring natural
  phenomena

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Observations

• 1. Observations (data) are the foundation of the
  scientific method . This observation might lead
  to a question regarding the event or
  characteristic. For example, you might drop a
  glass of water one day and observe it crashing to
  the floor near your feet. This observation might
  lead you to ask a question, "Why did the glass
  fall?"

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Hypothesis

• 2. Hypothesis In attempting to answer the
  question, a scientist will form a hypothesis (or
  some would say a guess) regarding the question's
  answer. In our example there are many possible
  hypotheses, but one hypothesis might be that an
  invisible force (gravity) pulled the glass to the
  floor.
• A hypothesis is a tentative explanations designed
  to guide experimentation
• A useful hypothesis must be testable and must be
  rejected or corrected when they conflict with
  experiment

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Hypothesis

• Notice that the hypothesis postulates a relation
  between the independent and dependent variable,
  one which produces the change, the other one in
  which the change is produced.
• The hypothesis should fit well with what we
  already believe about the natural order of
  things.

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Experimentation

• 3. Experimentation Of all the steps in the
  scientific method, the one that truly separates
  science from other disciplines is the process of
  experimentation. In order to prove, or disprove,
  a hypothesis, a scientist will design an
  experiment to test the hypothesis. Over the
  centuries, many experiments have been designed to
  study the nature of gravity. Let's look at one.

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Experimentation

• In the late 16th century, it was generally
  believed that heavier objects would fall faster
  than lighter objects. The Italian scientist
  Galileo thought differently.
• Galileo hypothesized that two objects would fall
  at the same rate regardless of their mass. Legend
  has it that in 1590, Galileo planned out an
  experiment. He climbed to the top of the Leaning
  Tower of Pisa and dropped several large objects
  from the top of the Leaning Tower.

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Experimentation

• What happens when you drop objects from the top
  of the tower? The two different objects fall at
  the same rate (as long as we ignore wind
  resistance).
• Data can be qualitative or quantitative.
  Quantitative data is obtained by making a
  measurement. Qualitative is descriptive data.

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Experimentation

• Accuracy indicates how close a measurement is to
  the accepted value. For example, we'd expect a
  balance to read 100.00 grams if we placed a
  standard 100.00 g weight on the balance. If it
  does not, then the balance is inaccurate.
• Precision indicates how close together or how
  repeatable the results are. A precise measuring
  instrument will give very nearly the same result
  each time it is used
• Data is most useful when collected under
  controlled conditions (experiments).
• Experiments must be repeatable and reproducible

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• The uncertainty of a measurement can be expressed
  in terms of accuracy or precision.

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Relative Error

• The accuracy of measurements can be determined by
  comparing your results with the accepted value.
• The percentage error, or relative error, of a
  measured value can be found with the following
  equation

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Develop a controlled experiment

• Develop a controlled experiment Now we will take
  a closer look at what goes into making a
  "controlled" experiment.
• variable - The quantities on which the outcome of
  an experiment depends are called variables.
• dependent variable - this will be the single
  observation, or the result we will be observing .
  In reality one would observe as many dependent
  variables as possible.

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Develop a controlled experiment

• independent variable - this will be the single
  variable we elect to manipulate. All of the other
  variables must now be held constant so they don't
  influence our dependent variable. This way any
  change that occurs to the dependent variable can
  be attributed to our independent variable.
• "control" - this will be the part of our
  experiment that does not receive the independent
  variable. This step is critical to the validity
  of a controlled experiment.
• trials - Make sure sufficient data is gathered to
  form a conclusion. (more the better)

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Develop a model or theory or Law Evaluate
Results

• 4. Develop a model or theory or Law Evaluate
  Results
• Galileo's experiment proved his hypothesis
  correct the acceleration of a falling object is
  independent of the object's mass. Why is this
  true? A few decades after Galileo, Sir Isaac
  Newton would show that acceleration depends upon
  both force and mass. While there is greater force
  acting on a larger object, this force is canceled
  out by the object's greater mass. Thus two
  objects will fall (actually they are pulled) to
  the earth at exactly the same rate.

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Theories

• A well-tested explanation for experimental data
  based on a set of hypotheses.
• It must be discarded or refined when they can't
  explain new experimental results

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Natural laws

• Natural laws compactly summarize patterns in a
  large amount of data often apply only under
  special conditions
• Natural laws are descriptions of nature, not
  explanations

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Errors.

• Errors are unavoidable in any experiment. No
  measurement is perfect.
• Two kinds of error
• random errors uncertainty of measurement, errors
  in reading a measurement, environmental factors
• systematic errors-design of experiment, faulty
  equipment, false assumptions or simplifications

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• Fifty Chevy Camaros used only unleaded gasoline
  while another fifty Chevy Camaros used the same
  type of unleaded gasoline plus STP additive. The
  autos with the STP additive averaged 23 better
  gas mileage than the autos that did not receive
  the STP. In this experiment, the gas mileage is
  the _____ variable.
• controlled
• dependent
• independent
• manipulated

Answer B
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• An experiment needs to be designed to determine
  how changing the slope of the ramp affects the
  amount of time it takes a ball to roll to the
  bottom of the ramp. The best way to design this
  experiment is to _____.
• change both the length and ball
• change only the ball used
• change only the height
• change only the ramp surface
• change the ramp surface and the height

Answer C
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• An investigation was conducted to determine how
  the amount of calcium chloride added to water
  affects the temperature of the water. In this
  experiment, the amount of calcium chloride is the
  _____ variable.
• controlled
• dependent
• independent
• responding

Answer C
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• An investigation was conducted to determine how
  the amount of magnesium sulfate added to water
  affects the temperature of the water. In this
  experiment, the temperature of the water is the
  _____ variable.
• controlled
• dependent
• independent
• manipulated

Answer B
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• To find out how much a person's weight changes in
  a year, you must know the _____.
• gender of the person
• person's weight at the beginning and end of a
  year
• person's weight four years ago
• type of food the person eats throughout the year
• weight of the person's parents during the year

Answer B
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• A personal opinion that offers an explanation for
  an observation is a(n) _____.
• dependent variable
• experiment
• hypothesis
• independent variable
• inference

Answer E
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• Mark watches a classmate kick his locker and says
  Boy, he must be mad at someone. Mark's
  statement is a(n) _____.
• dependent variable
• experiment
• independent variable
• inference
• observation

Answer D
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• Josie walks outside at noon, notices the sky is
  dark gray and predicts that it will rain soon.
  Josie's prediction is a(n) _____.
• dependent variable
• experiment
• independent variable
• inference
• observation

Answer D
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• Mickey has noticed that Karen wears a red shirt
  every Friday. This is an example of a(n) _____.
• dependent variable
• experiment
• independent variable
• inference
• observation

Answer E
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Other than the cup mentioned in the data table,
what laboratory equipment would you need to make
the necessary measurements? A   beaker, spring
scale B   beaker, triple beam balance C   graduat
ed cylinder, spring scale D   graduated cylinder,
triple beam balance E   test tube and triple
beam balance
Answer D
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Tables and Graphs
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Using Tables

• Making observations and collecting information is
  large part of a scientists job.

• Once this information is collected it must be
  organized and presented in a clear and concise
  way.
• Tables and Graphs are the tools that scientists
  use to organize and present information.

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Using Tables

• Tables consist of horizontal rows and vertical
  columns of information.

• Each row and column should have a heading that
  describes its contents.
• The table itself should have a title to describe
  its purpose.
• Identify the parts of the table on the following
  slide.

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Using Tables
Column
Title
Heading
Row
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Using Tables

• A table can hold a lot of information.

• Imagine how long it would take to write out all
  the information in this table in sentences.

• A table allows you to present all of the
  information on a single page.

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Using Tables

• Tables organize data efficiently.

• All of the data regarding problems with the video
  system is in a single row.

• All of the data regardingsoftware related
  problems is in a single column.

• The relationship between two variables is shown
  at the intersection of a row and column.
• The number of hardware problems with peripheral
  components is shown at the intersection of the
  hardware column and the peripheral row.

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Using Tables

• Use the table to answer the following questions.

• See if you notice a difference between the first
  two questions and the last two questions.

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Using Tables

• Which system has the most hardware problems?

• Video

• Users have the most difficulty with which system?

• Peripherals

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Using Tables

• What percent of hardware problems relate to the
  drives and RAM?

• 18.5

• What would you do to decrease initial problems?

• Send better instructions about the peripherals

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Using Tables

• How were the first two questions different from
  the last two?

• The first two questions could be answered by
  reading directly from the table. The last two
  questions required you to make some calculations
  and judgments about the data in the table.
• There is a lot more information in a table than
  what is written directly.
• The information in a table can be interpreted in
  many ways to draw conclusions and make
  predictions.

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Using Tables

• Construct a table that can be used to compare the
  features of various models of lawnmowers.

• The table should have a title and column and row
  headings. You dont need to put in the data.
  When you are done click to see an example.

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Using Circle Graphs

• While tables are used for organizing information,
  graphs are used to present information visually.

• Different graphs are designed to present
  different types of information.
• Circle graphs are best used to show how a whole
  is divided into its parts.

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Using Circle Graphs

• Circle graphs consist of wedge-shaped segments
  that together make a whole circle.

• Each segment should have a name and a value.
• The graph itself should have a title to describe
  its purpose.
• Identify the parts of the graph on the following
  slide.

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Using Circle Graphs
Title
Segment
Segment Name
Segment Value
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Using Circle Graphs

• Circle graphs are used to show how a whole is
  broken up into its parts.

• In this case, the whole is the total number of
  students asked about their lunch preference.
• The parts represent the 4 possible responses.

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Using Circle Graphs

• There are a few things you should notice about
  circle graphs.

• The segments must add up to the total.

17 for hot dogs
20 for sandwiches
23 for hamburgers
40 for pizza
100 total
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Using Circle Graphs

• There are a few things you should notice about
  circle graphs.

• The segment size must be relative to its value.
• 20 (1/5) of students chose sandwiches so that
  segment is 1/5 of the circle.

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Using Circle Graphs

• Use the graph to answer the following questions.

• See if you notice a difference between the first
  two questions, the next two questions, and the
  last question.

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Using Circle Graphs

• What percent prefer pizza or hamburgers?

• 63

• What is the least popular menu item?

• Hot Dogs

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Using Circle Graphs

• If 500 students were surveyed, how many preferred
  hamburgers?

• 115

• How many students preferred sandwiches?

• 100

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Using Circle Graphs

• Half the students (500 total) eat the school
  lunch every day. The other half will eat only
  when their favorite food is served. How many
  students can you expect to serve on pizza day?

• 350 ( 250 ( 250 x 40 )) 350

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Using Circle Graphs

• How were the first two questions different from
  the next two? How was the last question
  different?

• The first two questions could be answered by
  reading directly from the table. The next two
  questions required you to make some calculations
  and judgments about the data in the table. The
  answer to the last question was a prediction
  based on the circle graph.
• The information in a graph can be used in many
  ways to draw conclusions and make predictions.

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Using Circle Graphs

• Construct a circle graph to show the following
  data about bald eagle populations in 1998

• When you are done click to see an example.

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Using Bar Graphs

• While tables are used for organizing information,
  graphs are used to present information visually.

• Different graphs are designed to present
  different types of information.
• Bar graphs are best used to show how a number of
  objects or events compare in relationship to
  single property.

97
Using Bar Graphs

• Bar graphs consist of a horizontal and vertical
  scale.

• One scale identifies the objects to be compared
  the other scale is numerical.
• The bar graph gets its name from the lines that
  identify the measured value of each object.
• Identify the parts of the graph on the following
  slide.

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Using Bar Graphs
Title
Numerical Scale
Label
Bar
Object Scale
Label
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Using Bar Graphs

• Bar graphs are used to compare measurements taken
  from a number of objects or categories.

• In this case, the measurement is BTUs of energy
  consumption.
• The categoriesare the differentfuel types.

100
Using Bar Graphs

• There are a some important features of bar
  graphs. First, the numerical scale must be
  consistent

• Each division on the vertical scale is one unit.
  On this graph 1 unit 1 quadrillion BTUs
• Each division mustrepresent the same amount
  ofchange from thestart to the finish.

1 Quadrillion
1 Quadrillion
1 Quadrillion
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Using Bar Graphs

• The numerical scale must be consistent but there
  is no limit on the value you place on each
  division.

• Our graph was redrawn with a different scale. Now
  1 unit 2 quadrillion BTUs
• The scale is still consistent and the data is
  stillthe same but the graph looks different.

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Using Bar Graphs

• When each unit represents a larger value there
  appears to be less difference between the groups.

• A graph can be misleading or difficult to read
  depending on the scale you choose.

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Using Bar Graphs

• Use the graph to answer the following questions.

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Using Bar Graphs

• How much total energy was used by households in
  1997?

• 10.25 quadrillion BTUs

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Using Bar Graphs

• How many times as much natural gas is used
  compared to LP gas?

• Over 14 times as much

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Using Bar Graphs

• In this graph, a second bar was added for each
  category with data from 1979.

• This bar graph can then be used to compare the
  data from 2 different years.

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Using Bar Graphs

• What is the percent increase in total energy
  usage from 1979 to 1997?

• About 5

• What is the percent increase in electricity usage
  from 1979 to 1997.

• About 46

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Using Bar Graphs

• From 79 to 97 theUS population increased by
  17, electricity consumptionincreased 46, yet
  household energy consumption increased only 5.
  How can you account for this?

• The big increase in electricity use is probably
  related to the huge increase in electronic
  devices. The relatively small increase in total
  consumption is probably related to savings from
  more energy efficient devices.

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Using Bar Graphs

• Construct a bar graph to show the following data
  about US Endangered Animal Species

• When you are done click to see an example.

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Using Line Graphs

• While tables are used for organizing information,
  graphs are used to present information visually.

• Different graphs are designed to present
  different types of information.
• Line graphs are best used to show a relationship
  between two measured quantities.

111
Using Line Graphs

• Line graphs consist of a horizontal and vertical
  scale but both scales are numerical since each
  represents a measured quantity.

• Line graphs are drawn by connecting observed
  points where the two numerical quantities
  intersect.
• Identify the parts of the graph on the following
  slide.

112
Using Line Graphs
Title
Observed Points
Numerical Scale
Label
Numerical Scale
113
Using Line Graphs

• Line graphs are used to compare two measured
  quantities.

• In this case, the two quantities being compared
  are time and number of cell phone subscribers.
• The dots represent the points at which actual
  measurementswere made.

114
Using Line Graphs

• The points are located on the graph at the
  intersection of two measured quantities.

• In 1994, there were 24.134 million cell phone
  subscribers. In 1996, there were 44.042 million.

• Once the points are established a line is drawn
  to fit the data as well as possible.

115
Using Line Graphs

• The number of cell phone subscribers was actually
  counted in 1984, 1986, 1988, etc.

• But what was the count before 1984 or after 1998
  or in 1995?

• A line graph can be used to make predictions when
  no actual measurements were made.

116
Using Line Graphs

• To determine the number of cell phone subscribers
  in 1995, go up from 1995 to the line and over to
  vertical scale.

• According to the line graph there were about
  33 million cell phone subscribers in 1995.

• The line graph let us predict a value that we
  didnt actually measure.

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Using Line Graphs

• To predict the number of cell phone subscribers
  in 1999, you must extend the line then go up from
  1999 and over to the vertical scale.

• According to the line graph there may be about
  85 million cell phone subscribers in 1999.

• How is the 1999 prediction different from the
  1995 prediction?

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Using Line Graphs

• The 1995 prediction occurred between 2 measured
  points.

• The 1999 prediction occurred after the last
  actual measurement.

• In which prediction do you have the most
  confidence?

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Using Line Graphs

• The 1995 prediction is more reliable because we
  know what happened before and after. However, we
  dont know what happened after 1998.

• After 1998, cell phone subscriptions may continue
  to increase which is what we assumed.

?

• They may level off.

• They may decline.

• We cant be sure what will happen after 1998.

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Using Line Graphs

• How many cell phone subscribers were there in
  1991?

• About 8 million

• In what year did the number of subscribers hit
  55 million?

• In 1997

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Using Line Graphs

• Construct a line graph to show the following data
  about the percent of US high school dropouts

1975 13.9 1980 14.1 1985 12.6 1990 12.1 1995 10.5

• When you are done click to see an example.

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Using Line Graphs

• Match the type of graph with its use.

Used to compare several categories Shows the
relationship between two measured
quantities Shows a single measurement of a number
objects or events Shows how a whole is divided
into its parts. Used to make predictions and show
trends
Circle Graph Bar Graph Line Graph
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What does the graph indicate about the
relationship between distance and time? A   As
time decreases, distance increases. B   As time
increases, distance decreases. C   As time
increases, distance increases. D   Distance
remains constant while time increases. E   Time
remains constant while distance increases.
Answer C
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• After 7 seconds had passed, the temperature of
  the substance was approximately _____ degrees
  Celsius?
• 4
• 7
• 10
• 14
• 20

Answer D
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Temp (oC) Humidity Amount of mold after 2 weeks
0 Low None
0 High None
5.5 Low Small Amount
5.5 High Medium Amount
25.5 Low Medium Amount
25.5 High High Amount

• According to the data, what are the best
  conditions for growing mold?
• cold temperature and low humidity
• warm temperature and low humidity
• cold temperature and high humidity
• warm temperature and high humidity

Answer D
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• Paramecium caudatum was cultured first.
  Parameciumc aurelia was added to the same culture
  one day later. According to the graph, which is
  the first day that P. aurelia will exist alone in
  the culture medium if the trend shown continues?
• Day 12
• Day 13
• Day 16
• Day 18

Answer B
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Answer A

• According to the graph, what would most likely
  happen to bluegill sunfish if the temperature of
  the water in which they live were to rise above
  27C for a period of two weeks?
• The rate of ventilation would slow, and the fish
  would die of thermal shock.
• The rate of ventilation would increase to
  counteract low oxygen levels.
• The rate of ventilation would remain constant as
  the fish adapt to warmer water.