SCIENTIFIC METHODS
TARGETS
A. Tell how models are used in science.
B. Write the steps of the Scientific Method.
C. Identify questions and hypothesis’ that are
testable.
D. Distinguish descriptions and explanations.
E. Explain the importance of recording
procedures and results of an experiment.
Targets
F. Identify independent and dependent
variables in a controlled experiment.
G. Identify a control group, and explain the
importance of a control in an experiment.
H. Explain the importance of multiple trials
and using large sample sizes in an experiment.
I. Distinguish qualitative and quantitative data.
Targets
J. Tell the SI units of length, volume, mass
and temperature.
K. Describe positives and negatives of
developing new technologies.
L. Name the steps of the technological
design process.
I. How Science is Studied
A. Types of Investigations
1. Observing : Living things or events in nature.
2. Collecting Specimens : insects / rocks.
3. Research : Seeking more information.
4. Controlled Experiments : control variables.
5. Making Models
a. Types : pictures, drawings, 3-D, computer,
maps, globes, familiar objects.
b. Uses
 Show what something looks like on a scale.
 Show how something functions.
 Make predictions.
6. Review existing work.
B. The Scientific Method
1. ID a Testable Question
a. Testable questions should not :
 address opinions, preferences, moral values.
 address the supernatural.
 be vague or general
b. Testable questions should :
 address the natural world or something that
can be observed or measured.
 be specific
 Is football more fun to play than soccer?
Do more students prefer to play football
or soccer?
 Should stem cell research be expanded
or banned?
Can stem cells be used to cure some diseases?
 Do ghosts exist?
What percent of the population believe in ghosts?
How to grow larger tomatoes?
2. Research / Observations
 From reliable sources
or experts.
3. Develop a Hypothesis
Prediction or possible explanation.
 Written as a statement.
 Should be specific.
 Should be testable.
(dogs are happier than cats)
Which plant food will grow the largest tomatoes?
4. Collect Evidence / Experiment
5. Collect and Analyze Data
6. Draw Conclusions / Explanation
7. Share Results
C. Descriptions and Explanations
1. Descriptions include observations
and measurements.
2. Explanations are inferences and tells
how or why something occurred based
on clues or observations. (judgements)
II. Experimental Design
A. Procedure / Results Recorded
1. Experiment must be Reproducible.
2. Provide Evidence.
3. Reduce Bias : Allowing personal opinions
or expectations to influence results.
Belief not supported by evidence.
B. Constants / Variables
1. Independent: the variable that is changed.
(what is tested?)
2. Dependent: the responding variable.
(what is observed or measured?)
C. Control
1. Unchanged group or sample.
2. Used for comparison.
D. Multiple Trials and
E. Large Sample Size
1. More reliable and accurate results.
2. Reduce bias.
F. Data Described
 Qualitative : describes characteristics
 Quantitative : measured or counted
G. Informed Consent
 Experiment testing spontaneous generation.
 Francesco Redi
maggots on meat
(1668)
(control?)
(independent variable?)
(dependent variable?)
III. Collecting Data (metric or SI)
A. Base Units
1. Length
 Meters
2. Volume
 Liters
Graduated
Cylinder
3. Mass
 Grams
4. Temperature
 Degrees Celsius
(0 – 100C)
(32 – 212F)
B. Prefixes
 Kilo = 1,000
 Centi = 1/100
 Milli = 1/1000
IV. Microscopes
A. Simple Microscope
1. Importance
 Single celled things seen for the first time.
 Multi celled things understood better.
2. Anton Van Leeuwenhoek
B. Compound Microscope
 Stereo Scopes
C. Complex Microscopes
Electron : most powerful (1,000,000 vs 1,000)
V. Science and Technology
A. Technology is the use of tools or methods to
help do things better.
1. Positives : improved goods / services,
quality of life.
2. Negatives : automation?, warfare, threats to the
environment. (in conflict w/environment)
B. Technological Design Process
1. ID the Problem
2. Look for Solutions
3. ID the Constraints
(limits on cost, time, materials, and
environmental effects)
4. Design a Solution
5. Test and Evaluate, revise if necessary
NOTES ON PELLAGRA
What was the problem of pellagra?
• In 1914, pellagra was a disease in the U.S. In order to
cure / prevent it, scientists tried to figure out what
caused it.
What did people think caused pellagra.?
1. Eating corn
3. Bacteria / germs
2. An insect
4. Lack of nutrition /
poor diet
NOTES ON PELLAGRA
What evidence was observed about pellagra?
• Pellagra was common in the South; in poor areas and institutions.
• Many people in the South ate a poor diet.
• Staff at institutions did not have pellagra.
• Orphans provided with a better diet either recovered from
pellagra or did not get it.
• Some prisoners fed a poor diet developed pellagra.
When provided a better diet, they recovered.
What did Dr. Goldberger conclude about the cause?