Scientific Process Skills
Objective 1: the student for at least 40% of
instructional time, conducts laboratory and field
investigations using safe and ethical practices
Objective 2: the student uses scientific methods
to solve investigative questions
Objective 3: the student uses critical thinking,
scientific reasoning, and problem solving to make
informed decisions within and outside the
classroom
Material Safety Data Sheet
The MSDS for a
chemical is a document
that lists the
manufacturer, physical
and chemical
properties, health
hazards, precautions for
safe handling, exposure
limits, first aid, and
other hazard data
Hazard
Possible
Effects
Corrosive
Damages tissue or
surface on contact
Flammable
Causes fires or ignition
(burns or ignites easily)
Radioactive
Damages tissue by
removing electrons or
breaking bonds;
carcinogen
Toxic
Can damage or kill by
exposure via inhalation,
skin contact, or ingestion
Common
Symbol
Laboratory Safety Rules and Equipment
1. Read and understand all safety rules and labels
2. Follow directions and use the equipment only as instructed
3. Locate the emergency exit and safety equipment, including the
eyewash station, fire blanket, and fire extinguisher
4. Wear required safety equipment, such as safety goggles, apron,
and gloves when instructed to do so
5. Tie back hair and loose clothing
6. When diluting, pour chemicals into water, not water into chemicals
7. Do not return unused chemicals to the container
8. Report all accidents, spills, and broken glass to the instructor
9. Avoid eating, drinking, or directly smelling chemicals
10. Point test tubes that are being heated away from you and others
11. Clean up your area, tools, and hands when done
12. Turn off equipment when finished
Scientific Investigation
*Science includes the design and application of testable
statements and predictions regarding natural phenomena.
Scientific questions can be explored through different
types of investigations.
Investigation
Example
Descriptive
Use a thermometer to measure the heat of a
reaction
Comparative
Use pH scale to compare the acidity of
several liquids
Experimental
Test the effect of temperature on the
solubility of solutions
Scientific Method
1. Begin with a well-defined question
2. Learn, research, and collect information about your question
3. Make a hypothesis, a prediction about what might happen.
It is a statement (often if/then) that must be able to be
tested (not just opinion).
4. Design and conduct an experiment to test your hypothesis.
Change only the variable that you are testing.
5. Collect and organize observations in a table, graph, or any
other means of visual presentation.
6. Evaluate the data and make inferences. Look for patterns
and use models or mathematical approximations to describe
the data.
7. Make a valid conclusion. Do the results support the
hypothesis?
Types of Variables
Variable
Description
Independent
Variable that is manipulated during the
experiment; it is shown on the x-axis
(horizontal)
Dependent
Variable that responds to changes in the
independent variable; its value is measured; it is
shown on the y-axis (vertical)
Controlled
Variable that is held constant during the
experiment
Types of Observation
Observation
Description
Quantitative
Involves measurements such as mass,
temperature, and volume
Qualitative
Uses descriptions such as color, clarity, and
precision
Laboratory Equipment
Equipment
Purpose
Beaker
Holds liquids; a wide mouth cylindrical container
Burette
Dispenses precise liquid amounts via a vertical tube
Balance
Measures mass in grams
Erlenmeyer flask
Holds liquids; conical base with a cylindrical neck
Graduated
cylinder
Measures the volume of liquids
Pipette
Transfers small amounts of liquids using a thin tube
Test tube
Holds small amounts of chemicals
Thermometer
Measures the temperature of a substance
Volumetric flask
Holds liquids; conical base with a cylindrical neck with
volume derivations drawn on
Explanations, Data Evaluation, & Representation
•
•
•
•
•
We evaluate scientific explanations using evidence, logic,
and investigations.
We extract and consider information from different
sources, like scientific journals, news reports, and
marketing materials
We formulate a hypothesis about what might happen; a
prediction based on observations and can be repeatedly
tested
We develop theories based upon our tested data; a wellestablished inference, reliable explanation that has been
tested by multiple people under varying conditions
Example: the Big Bang Theory states that all the matter
in the universe was once contained in a single subatomic
particle which exploded and is continuing to expand,
even today.
Explanations, Data Evaluation, & Representation
Term
Description
Average/mean
Sum of values divided by numbers of items
Precision
Closeness of values to each other (repeatability)
Accuracy
Closeness to the “true” or “correct” value
Percent error
(accepted value - experimental value) (100)
accepted value
High precision, low accuracy
High accuracy, low precision
Rules to determine the number of significant figures:
• For scientific notation, all digits of coefficients are
significant
• For “regular” numbers:
– Non-zero digits are significant
– Zeros between non-zero digits are significant
– Zeros both to the right of the decimal point and also to
the right of a non-zero digit are all significant
– Leading zeros are NOT significant
*Examples: significant figures
14 2 sig.figs.
14.03 sig.figs
0.0091 sig.fig.
1.0094 sig.figs.
32,000  2 sig.figs.
3.081x1054 sig.figs.
2.00x10-93 sig.figs.
2x10-9  1 sig.fig.
Mathematic Operations With Significant Figures
Operation
Significant Figures in Answer
Example
Addition /
Subtraction
Limit the answer to smallest
place value on least precise
number you began with
5.01 + 1.001 =
6.01
(3 sig.figs.)
Multiply /
Divide
Limit the answer to the least
number of significant figures
that you started with
1,200 x 0.245 =
290
(2 sig.figs.)
Dimensional Analysis
• Method to convert units using equivalent values in different
units
• Place one value in the numerator and the equivalent value in
the denominator (the fraction’s value is now 1)
• Multiply this fraction to convert a value to different units
• Carefully write out all units to check your work
• Example:
– There are 760mmHg in 1atm; so 760mmHg/1atm = 1 or
1atm/760mmHg = 1
– How many mmHg is 0.89atm?
0.89atm
x
760mmHg
= 680mmHg
1atm
International System (SI) Units
Metric (SI) system: uses metric (SI) prefixes that represent
powers of 10
kilo(k) hecto(h) deka(da)
1,000
100
10
Base
Base
Base
units
units
units
larger unit
base
1
Base
unit
deci(d) centi(c) milli(m)
0.1
0.01
0.001
Base
Base
Base
unit
unit
unit
smaller unit
*Smaller prefix values include micro (μ) = 10-6 and nano (n) = 10-9
Conversions and Constants
Unit Conversions
Metric (SI) Conversions
• It takes more of the smaller
unit to equal the larger unit
• Use equivalent values of the
initial and final units to find
a unit of conversion factor
(fraction’s value is 1)
• Multiply by this fraction to
convert between units
• Set up a proportion using
the metric prefix values
discussed earlier
• If using scientific notation,
keep the coefficient the
same and change only the
power of ten
Example: A wave travels 2.4 meters
each second. How far will it travel in
one hour?
Examples: Convert 55.1mL to kL.
2.4m x 60s x 60min = 8.6x103m/hr
1s
1min 1hr
55.1mL x __1L__ x _1kL__ = 5.51x10-5kL
1000mL 1000L
End of Objective 1,2,3 notes