Title: PREPARE FOR LABORATORY WORK
1PREPARE 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.
2DRESS 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
3BUNSEN 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.
4BUNSEN 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.
5AVOID 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.
6ANIMAL SAFETY
- Do not cause pain, discomfort , or injury to an
animal. - Wash hands after handling animals
7SAFETY 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.
8SAFETY 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.
9SAFETY 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.
10SAFETY 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.
11SAFETY 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.
12SAFETY 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.
13BLOODBOURNE 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.
14BLOODBOURNE 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.
15CLEAN UP
- Consult teacher for proper disposal of chemicals.
- Wash hands thoroughly, following experiments.
16IN 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.
17- 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
24Science Equipment and Taking Measurements
25Quantity Instrument Units
Mass Balance Grams
Volume Graduated Cylinder Milliliters
Length Ruler Centimeters
Temperature Thermometer Degrees Celsius
Time Stopwatch Seconds
26Triple beam Balance measures mass
Thermometer measures temperature
Graduated Cylinder measures volume
Stopwatch measures time
Meter stick measures length
27Reagent Bottle
Florence Flask
Erlenmeyer Flask
Test Tube Rack
Test Tube Clamp / Holder
Test Tube
28Watch Glass
Bunsen Burner
Alcohol Burner
Evaporating Dish
Petri Dish
Microscope
29The 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.
30(No Transcript)
31Erlenmeyer 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.
32Erlenmeyer Flasks and Beakers
33Graduated 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.
34Graduated Cylinders
35Water 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.
36Balances
- 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.
37Balances
- 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.
38 39Metric 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
40Graduated Cylinders
What is the volume?
About 36.3 ml (dont forget to read from the
bottom of the meniscus and to estimate a digit.
41Triple Beam Balance
What is the mass?
356 g
42Ruler
What is the length of the nail?
4.08 cm
43Thermometer
What is the temperature?
47o C
44The volume of the object is_________. AÂ Â Â 8
mL BÂ Â Â 11 mL CÂ Â Â 16 mL DÂ Â Â 21 mL EÂ Â Â 27 mL
Answer B
45- 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
46Parts of an Experiment and the Scientific Method
47Scientific Method
- The scientific method is a systematic procedure
for solving problems and exploring natural
phenomena
48Observations
- 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?"
49Hypothesis
- 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
50Hypothesis
- 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.
51Experimentation
- 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.
52Experimentation
- 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.
53Experimentation
- 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.
54Experimentation
- 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
55- The uncertainty of a measurement can be expressed
in terms of accuracy or precision.
56Relative 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
57Develop 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. -
58Develop 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)
59Develop 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.
60Theories
- 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
61Natural 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
62Errors.
- 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
63- 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
64- 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
65- 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
66- 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
67- 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
68- A personal opinion that offers an explanation for
an observation is a(n) _____. - dependent variable
- experiment
- hypothesis
- independent variable
- inference
Answer E
69- 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
70- 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
71- 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
72Other than the cup mentioned in the data table,
what laboratory equipment would you need to make
the necessary measurements? AÂ Â Â beaker, spring
scale BÂ Â Â beaker, triple beam balance CÂ Â Â graduat
ed cylinder, spring scale DÂ Â Â graduated cylinder,
triple beam balance EÂ Â Â test tube and triple
beam balance
Answer D
73Tables and Graphs
74Using 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.
75Using 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.
76Using Tables
Column
Title
Heading
Row
77Using 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.
78Using 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.
79Using 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.
80Using Tables
- Which system has the most hardware problems?
- Users have the most difficulty with which system?
81Using Tables
- What percent of hardware problems relate to the
drives and RAM?
- What would you do to decrease initial problems?
- Send better instructions about the peripherals
82Using 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.
83Using 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.
84Using 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.
85Using 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.
86Using Circle Graphs
Title
Segment
Segment Name
Segment Value
87Using 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.
88Using 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
89Using 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.
90Using 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.
91Using Circle Graphs
- What percent prefer pizza or hamburgers?
- What is the least popular menu item?
92Using Circle Graphs
- If 500 students were surveyed, how many preferred
hamburgers?
- How many students preferred sandwiches?
93Using 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
94Using 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.
95Using 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.
96Using 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.
97Using 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.
98Using Bar Graphs
Title
Numerical Scale
Label
Bar
Object Scale
Label
99Using 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.
100Using 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
101Using 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.
102Using 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.
103Using Bar Graphs
- Use the graph to answer the following questions.
104Using Bar Graphs
- How much total energy was used by households in
1997?
105Using Bar Graphs
- How many times as much natural gas is used
compared to LP gas?
106Using 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.
107Using Bar Graphs
- What is the percent increase in total energy
usage from 1979 to 1997?
- What is the percent increase in electricity usage
from 1979 to 1997.
108Using 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.
109Using 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.
110Using 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.
111Using 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.
112Using Line Graphs
Title
Observed Points
Numerical Scale
Label
Numerical Scale
113Using 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.
114Using 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.
115Using 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.
116Using 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.
117Using 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?
118Using 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?
119Using 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.
?
- We cant be sure what will happen after 1998.
120Using Line Graphs
- How many cell phone subscribers were there in
1991?
- In what year did the number of subscribers hit
55 million?
121Using 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.
122Using 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
123(No Transcript)
124What does the graph indicate about the
relationship between distance and time? AÂ Â Â As
time decreases, distance increases. BÂ Â Â As time
increases, distance decreases. CÂ Â Â As time
increases, distance increases. DÂ Â Â Distance
remains constant while time increases. EÂ Â Â Time
remains constant while distance increases.
Answer C
125- After 7 seconds had passed, the temperature of
the substance was approximately _____ degrees
Celsius? - 4
- 7
- 10
- 14
- 20
Answer D
126Temp (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
127- 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
128Answer 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.