Bio Unit 1: Science Safety and
Evidence Based Thinking
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Lab Safety
Lab Equipment
Accuracy and Precision
Measurements
Scientific Method
Charts and Graphs
SAFETY
1. Always obtain the instructor’s
permission before beginning a lab.
SAFETY
2. Read the procedure
(more than once)
before beginning the
experiment. Ask the
instructor if you have
any questions.
SAFETY
3. Always wear safety goggles.
SAFETY
4. Always point
the mouth of a
test tube away
from yourself
and others.
SAFETY
5. Never eat or drink
anything in the lab.
SAFETY
6. Remember if you
need to smell a
substance, waft it
toward your nose.
Do not directly smell
the chemical.
SAFETY
7. When diluting an acid, always
pour the acid into the water.
SAFETY
8. Reactions that
produce toxic
fumes should be
performed under
a fume hood.
SAFETY
9. Know the location of all the
safety equipment in the lab.
SAFETY
10. Long hair, loose clothing, and
jewelry should be secured and tied
back during lab procedures.
SAFETY
11. Do not handle hot or cold
containers with your bare hands.
Use the proper holder for the
container.
SAFETY
12. Report any and all accidents to the
teacher immediately, no matter how
big or small.
SAFETY
13. Ask the teacher for the proper
way to dispose of any material.
SAFETY QUESTIONS
• Now answer the safety practice questions
Safety symbols
Biohazard
Biological materials that
could be harmful.
Toxic or Poisonous
Corrosive
Corrosive means
capable of
destroying or eating
away by chemical
means.
Flammable
Easily set on
fire.
Safety Goggles
Goggles MUST be
worn at all times
while in the lab.
Open Flame Alert
Be careful when using an open flame
as an explosion could occur.
Lab Equipment
Beaker
• A beaker is used to
hold liquids.
• It is not precise
enough to make
good
measurements.
Graduated Cylinder
 Used to measure
liquid volumes
(mL).
meniscus
Always read a graduated
cylinder from the bottom
of the meniscus.
Pipette
• Pipettes are used to measure small
amounts of liquid.
• They are very precise.
Test Tube
• A test tube is
used to hold or
store liquids.
• It is not a precise
measuring
instrument.
Test Tube Rack
• A test tube rack is
used to hold and
support test
tubes.
Test Tube Clamp
• Test tube clamps
are used to hold a
test tube while its
contents are
being heated.
Triple Beam Balance
• A triple beam
balance is used
to measure
mass (kg).
Funnel
• A funnel is used to
transport
materials from
one container into
another container.
Erlenmeyer Flask
• An Erlenmeyer
flask is used to
hold and mix
liquids.
• It is not precise.
Ring Stand
• A ring stand is
used to hold
objects.
Bunsen Burner
• A Bunsen burner uses
natural gas to provide
a heat source.
Tongs
• Tongs can be
used when
handling hot
or cold
objects, such
as beakers.
Accuracy & Precision
Accuracy & Precision
• Accuracy = refers to how “correct” the
answer is (hitting the bull’s eye)
• Precision = refers to how small a scale is
being used to make a measurement or
how close measurements are to each
other.
Accuracy
• This is when a
measurement is closest
to its true value.
• The exactly correct
answer.
• The bull’s eye.
Precision
• This is the repeatability of a
measurement.
• It may or may not be accurate
• Precise, but not
accurate.
• Accurate and
precise.
• Not accurate or
precise.
A
C
B
D
A=high precision, high accuracy
B=low precision, high accuracy
C=high precision, low accuracy
D=low precision, low accuracy
Measurement
Tools for Measurement
•Clocks and stopwatches measure time.
•A balance is used to measure mass.
•A graduated cylinder, dropper, or Erlenmeyer
flask is used to measure volume.
Length
• The standard unit of
measurement to determine
length is a meter (m).
• It measures the distance from
one point to another.
• A ruler or meter stick are most
commonly used to determine
length.
Mass
• Mass is the measure of the amount of matter
an object has.
• It is measured in grams (g).
• The tool for measuring mass is the triple beam
balance.
Volume
• Volume is the amount of space
occupied by an object.
Volume
• The units for volume are cubic
centimeters (cm3) or milliliters (mL).
Volume
• The volume of a regular object can be
determined mathematically.
– For example, the volume of a cube is length
x width x height.
Volume
• The volume of
irregular objects
can be
determined by
displacement.
Density
• Density is the mass of an object divided
by its volume.
• It is measured in g/cm3.
• Density helps explain why
things float.
Temperature
• Temperature measures how hot or cold
something is.
• All measurements for temperature are taken
in degrees Celsius.
• The SI unit for
temperature is
Kelvin (K).
Temperature
• A thermometer is the most common
tool for measuring temperature.
Conversions
Converting SI units
• Remember:
Kevin Has Diarrhea U Don’t Call Mom!!
• K H D(da) u d c m
• Move the decimal point the correct number of
spaces in the proper direction!
For example: 2L = ? mL
1
2
3
Step #1
k h da u d c m
(remember that u = meters, liters & grams)
Step #2 – determine how many spaces are between u and m
Step #3 – move the decimal in the original problem the same number of
spaces and in the same direction for your answer.
1
2
3
2. 0 0 0 .
• Therefore 2L = 2000mL
• Remember to move the decimal the
same direction that you moved on the
chart!!
Practice problems
1. 35 hg = ? dg
2. 2.56 kg = ? cg
3. .065 mL = ? hL
Scientific Method
- a series of steps used by
scientists to solve a problem
• What is the scientific method? It is a process that is used to
find answers to questions about the world around us.
• Is there only one scientific method? No, there are several
versions of the scientific method. Some versions have more
steps, while others may have only a few. However, they all
begin with the identification of a problem or a question to be
answered based on observations of the world around us and
provide an organized method for conducting and analyzing an
experiment.
• What is a hypothesis? It is an educated guess based on
observations and your knowledge of the topic.
• What is data? It is information gathered during an
experiment.
How Do Scientists Solve Problems?
The Scientific
Method
Identify the Problem (make an observation)
What do you want to know or explain? Use observations you have made to write a question that
addresses the problem or topic you want to investigate.
Form a Hypothesis
What do you think will happen? Predict the answer to your question or the outcome of the
experiment.
Yes
No
Conduct an ExperimentIs your
Modify the Experiment
Yes
Follow the steps in your procedure
to
perform
your
experiment.
Record
data and observations!
data inaccurate or
Rewrite your procedure to address
the
experiment
flawed?
the flaws in the original experiment.
No
Analyze the Data
Is the data reliable? Does your data and observations from the experiment support your hypothesis?
No
Yes
Is the data inaccurate or
the experiment flawed
Modify the Experiment
Rewrite your procedure to address
the flaws in the original
experiment.
Make a Conclusion
Write a conclusion that summarizes the important parts of your experiment and the results
.
1. Make an observation.
• Use your senses (sight, hearing,
touch, etc.) to make observations.
2. Form a Hypothesis
• A hypothesis is an educated
guess. It must be testable.
3. Conduct an Experiment
• Design and conduct an experiment
to test your hypothesis.
4. Record and Analyze the Data
• Record and organize the data from
the experiment.
• Analyze the results so that a
conclusion can be formed.
5. Make a Conclusion
• After analyzing your
results, make a
conclusion.
• Determine if your
hypothesis was
right or wrong.
Scientific Theory
• Theories are based upon
experimental data.
• Confirmed by repeated
experiments.
• Modified as new
information is gathered.
Scientific Law
• Theories become Laws when nothing
changes for hundreds of years.
• Laws become theories again when new
information changes them.
Experiments
The Independent Variable is the
variable that can be manipulated or
changed by the scientist.
The Dependent Variable is the variable
that changes because of the independent
variable. It must be measured, counted,
or observed.
The control is the part of the
experiment that is held constant. It
is used for comparison.
The factors that must remain the same in
each experimental setup are the
constants.
Experimenting
• You are planning to grow tomatoes in
your garden, but you don’t know what
the best kind of fertilizer would be. At
Wal-Mart you find 3 different fertilizers
for tomato plants.
• Design an experiment to test which
fertilizer is best.
 What would the independent variable be?
 The type of fertilizer
 What would the dependent variable be?
 The growth of the tomato plants and the amount
of fruit they produce.
 What is the control?
 The control would be the plants where NO fertilizer
was added.
 What are the constants?
 The constants could include the amount of water,
type of soil, type of tomato plant, initial size of
plant, size of their containers, etc.
Analysis of Data
Charts, Tables, and Graphs
Analysis of the Data
• Data tables, flow charts and graphs present the
information collected during an experiment.
• What the data shows, any trend in information
is explained in the analysis of data.
• Qualitative Data is data that uses
words, describing certain
characteristics. (it is cold outside)
• Quantitative
Data – numerical
data, gives
precise amounts
(it is 32o outside)
• Graphs are used to organize
data.
Pie or Circle Graphs
Pie graphs
represents
parts or
percents of a
whole.
Line Graph
• A line graph
uses plotted
data points and
lines to show
the relationship
between
variables.
Bar Graph
• A bar graph
compares data
using bars of
different heights
and lengths.
Data Table
Columns
• A data table
organizes
data into
rows and
columns.
Rows
Reading Tables and Graphs
1. When a question includes a table or graph,
read it first, before reading the question.
Don’t just Look at it READ IT.
While you are reading the graph, pay
attention to the following:
2. What is the title, what is being measured or
compared? What units (grams, mLs, minutes,
years) are given? Are the numbers or slope
increasing, decreasing?
After reading the data, now read the
question!
• The table shows environmental factors and soybean
production for three regions. Which of the following probably
accounts for the decrease in soybean yield in Region 1?
F High levels of ozone damaged
the soybean plants, decreasing
the average yield.
G Low rainfall amounts failed to
meet the plants’ moisture
needs and inhibited growth.
H Poor mineral levels found in
the soil in that region limited
the soybean harvest.
J Higher-than-normal rainfall
increased pest activity,
decreasing the average yield.
What do you have to know?
*1st you really only have two choices, decreased rainfall, or O3 level.
*Since the rainfall did not decrease consistently (it actually increased in 1999) that
would not be a good answer.
*Therefore, it must be the O3, which is the chemical formula for ozone.
Answer?
F
Reading Graphs
Always read the title.
Read the x- & y-axis
labels & UNITS.
What is happening?
As the pressure of
oxygen increases,
the % saturation is
increased.
Match the type of graph with its use.
Used to compare several categories
Circle Graph
Shows the relationship between two
measured quantities
Bar Graph
Shows a single measurement of a
number objects or events
Line Graph
Shows how a whole is divided into
its parts.
Used to make predictions and show
trends
Inference
An inference is an explanation based
on observations or trends.
For example, if you wake up in the morning and
see water on your car and on the ground, you
could infer that it rained even though you did not
actually see it happen.