September 13
Warm-up Q:
Announcements:
Please be sure to
purchase note
blanks prior to
next week
Important Dates: (that means…write it down in your calendar)
Thursday, September 12: Field day (dress appropriately)
Flipped classroom note taking:
Directions: Open up to “Scientific Process” NOTE
BLANKS
1) Read the introduction
2) Fill in the Scientific Process Skills using the reading
3) Use following slides to complete note blanks at
home.
Spontaneous Generation:
The idea that living things come from
non-living things.
Such as mice from wheat
Or flies come from rotten meat
This may seem silly to us today; but can you imagine why people may have thought this in the
past?
Spontaneous Generation was:
Developed by Aristotle
Dispelled by Louis Pasteur
We will use the experiment Louis
Pasteur developed as an example of
the scientific method.
Why?
Because it has to do with
Biology!
Plus it is considered by many
to be the first time the
scientific method was really
used in the way that it is today.
Use the following format for all your
lab write ups!
1) Start with a
problem
statement:
• Question based on
observation that will be
answered in the
experiment. You write it
in the form of a
question:
“What is the effect of
(manipulated variable)
on (dependent
variable)?”
Ex: What is the effect of air
traveling through a swan neck
flask on the ability of
microorganisms to grow in
sterile broth inside the flask?
2) Formulate a
Hypothesis
(prediction backed up
by reasoning):
• If (manipulated variable)…
then (responding variable)…
Pasteur predicted that…
because (relevant
Microorganisms carried in the air caused
explanation).
growth of organisms
OR
Ex: If a sterilized broth is
• IF (the M.V.) IS (describe how you
exposed to air through a swan
change it), THEN (the R.V.) WILL
neck flask, then it will remain
(describe the effect) BECAUSE …
free of microorganisms
(give a reason for your
because the swan neck will
prediction).
capture any microorganisms
that are carried in the air.
3) Identify the
variables:
• INDEPENDENT/Manipulated:
The variable that is changed/
variable that investigator
Ex:
“manipulates”
Manipulated variable:
exposure to air through a
• DEPENDENT/Responding:
swan neck flask
The variable that is measured
due to the change
Responding variable: growth
of microorganisms in broth
Control (fixed) variables: variables
that do not change
• Must have minimum of three
control variables
• They must be relevant to
your investigation.
• all variables that may
reasonably affect the
outcome of the investigation
must be controlled
• Materials used and
measurement techniques
are NOT controlled variables
(they are validity measures).
Ex:
-Temperature at which
flasks are stored
-Time that flasks are
allowed to sit
-Amount of light that
flasks are exposed to
4) Identify the Groups:
• Experimental group- set-up
that has the manipulated
Ex:
variable
• Control group- set-up
without the manipulated
variable
**Needs to be included in the
procedure
Experimental groups:
- sterilized broth in broken
flask
- sterilized broth in swan
neck flask (has air)
Control group: sterilized
broth in sealed swan
neck flask (does not
have air)
5) Materials and Apparatus list:
• Bulleted list
• Includes quantities and
size
– Be as specific as possible
(example: ‘50 mL beaker’
instead of ‘beaker’); include
the volumes of tubes and
cylinders, the
concentrations of solutions,
the model and
manufacturer of any
complex apparatus. If you
have to decide how much of
a substance or a solution to
use, state your reasoning or
show the calculations.
Ex:
• 9- 500mL swan neck flasks
• 3 Liters of nutrient rich broth
• 1- bunsen burner
• 1- glass cutting pliers to
remove swan neck
6) Procedure:
• Include a DIAGRAM OR PHOTOGRAPH
of how you set up the experiment. Be
sure your diagram includes a title and
any necessary labels.
• Diagram includes labels and should
be 1/3 to half a page in size.
• Numbered steps
• Logical steps to repeat the lab
– Explains how to set-up control and
experimental groups
– Include what and when to record
data
– Your procedure must include a few
VALIDITY MEASURES. Validity
measures are things kept constant
to make sure experimental
measurements are valid and
consistent.
• Indicate trials/ reliability measures
Experimental Groups:
3 flasks without swan neck with 300mL
of broth
3 flasks with swan neck and 300mL of
broth
Control Group:
3 sealed flasks
with 300 mL of
broth
Ex:
-Thoroughly rinse and dry glass
ware prior to using to ensure
that glass ware is sterile
-Make sure that all four broth
solutions come to a complete
boil
Ex:
-Set up three swan neck
flasks without the neck, and
three swan neck flasks with
neck intact for reliability
7) Data Collection:
• Record data accurately and neatly
• May includes both qualitative and
quantitative data
• Data table must include appropriate
units in the headings, and a DESCRIPTIVE
title
• Averages are included when trials are
indicated
• See sample data table
Sample Data Table:
Descriptive title
Responding Variable
(+ unit of measurement):
Manipulated Variable
(+ unit of measurement):
Trials
Levels of MV
#1
#2
#3
Average of Trials
This table can be made using MS Word, MS Excel or by hand.
Data Tables drawn by hand:
Use a ruler.
Neat and legible.
Make it big enough that I can read it!
8) Data Analysis:
•Process data in a meaningful way
•Include graphs and or mathematical calculations
ex: calculations for taking an average
•Look for patterns and trends
Graph: See example on next slide
Variables listed with units of measurement
Even increments on both X and Y axis
Ruler used whenever hand drawn for all straight
lines
TITLE
Describes what you are
studying
Y-AXIS
Responding
Variable & Unit of
Measurement
NEATNESS
•Ruler is used for lines on
the graph
•Ruler is used for the X
and Y axis lines
•Legible handwriting
X-AXIS
Manipulated Variable &
Unit of Measurement
KEY
Identifies
different sets of
data found in
your graph
(should be colorcoded)
9) Conclusion:
4 parts
1) State whether your hypothesis is “supported” or “not
supported”
2) Evidence that your hypothesis is supported or not
supported…. Use concrete data. Use range of data when
available
3) Errors/improvements (realistic)
4) Modifications to the procedure
Reminders:
•NO ABBREVIATIONS
•Include all the parts indicated in the directions
•Metric, metric, metric……