Welcome!
Please get out your Scientific Method
Review sheet and read the board.
Eaarth tips:
Post paper before the rush!
Make sure you’ve answered all the
questions!
FB group
Your own work
When you put cut flowers in water, adding a
teaspoonful of sugar to the water will make the
flowers last longer.
 Why is it important that there is more than one group in
this study?
 Why is it important that there is only ONE thing that is
different between the two groups?
 Why is it important that all other things be the same
between the two groups?
 Could you have more than two groups? What might
they look like?
A number of studies indicate that if people eat a
diet that is low in fat, then their chance of getting
colon cancer will be decreased.
 What is the ONE thing that is different between
the two groups?
 What other factors/conditions/characteristics
must be the SAME between the groups?
 What will be measured/counted at the end?
 What might be an appropriate hypothesis for this
study?
The mercury preservative used in some childhood
vaccines can cause autism-like symptoms in
newborn mice, but only in those with a particular
genetic susceptibility, according to a Columbia
University study.
 What is the ONE thing that is different between
the two groups?
 What other factors/conditions/characteristics
must be the SAME between the groups?
 What will be measured/counted at the end?
 What might be an appropriate hypothesis for this
study?
Doctors at the Latter-Day Saints Hospital in Salt Lake City,
Utah, have determined that patients that receive antibiotics
more than two hours before or two hours after surgery are
six times more likely to develop an infection than those
patients that receive antibiotics within a two hour window
before or after surgery.
 What is the ONE thing that is different between the two
groups?
 What other factors/conditions/characteristics must be the
SAME between the groups?
 What will be measured/counted at the end?
 What might be an appropriate hypothesis for this study?
Now you try it!
Reteach
 Definitions of control group and controlled
variables – how are they different?
 If a variable is the independent variable, can it
also be a controlled variable?
 How does using the words If/then in a
hypothesis help you identify the independent vs.
dependent variable?
 “Controlled variables” refers to components that
are the same BETWEEN control and
experimental groups
Beyond the science fair
Methods of scientific study
Learning objective:
To define the methods of scientific study
that you’ll encounter this year and then to
compare their advantages and
disadvantages.
To practice effective note taking
Lab Studies: Appropriate uses
When all variables can be controlled
When set up can provide information that
reflects real world
When many trials are needed
(hundreds/thousands?)
Example: Testing to see if sunflowers can
be used to remove lead from
contaminated soil.
Animal Studies: Appropriate uses
 Before a substance is tested on humans
 When all variables can be controlled (clones can
be used to control genetic differences!)
 When set up can provide information that
reflects real world
 When many trials are needed
(hundreds/thousands?)
 Example: Testing a new HIV treatment or
testing a consumer product like eye makeup
Epidemiological Studies: Appropriate
uses
Compares groups of people
May be blind or double blind
May follow people for decades
Surveys identify appropriate study
subjects
Example: Do Japanese people who eat
traditional diets have less heart disease
than those who have adopted a Western
diet?
Case Studies: Appropriate uses
Provides information about humans (not
animals)
Compares groups of people as
epidemiological studies
Case data is gathered from doctors and
hospitals by the researcher
Usually for something that rarely occurs
Example: Studying the effects of lead on
the children of Galveston
Field research: Appropriate uses
Events or subjects studied in natural
setting.
Often compares two areas: one with the
IV, one which lacks the IV (for control)
RULE!!!!: Do no harm!
Example: Study the effects of fire on
native seed germination rates.
Check for understanding: Which type
would you use?
What is the effect of different plowing
methods on soil nutrient loss?
Do the elevated levels of Ritalin in our
drinking water cause health problems?
What are the best conditions for
biodegradable plastic to break down?
Now let’s compare the types
Lab studies vs. Field – what are the
advantages and disadvantages?
Case studies – How is this limited?
Epidemiological studies vs. Animal testing
– advantages/disadvantages?
Write in at least one advantage and
disadvantage for each type.