PRE-LAB ASSIGNMENT (Due the beginning of the class period of the lab)
• Counts 20% of the laboratory grade. • Before coming to lab, identify the
experimental characteristics listed below
• Be neat. •
• Date each entry.
• You may work together, but copying another
person’s pre-lab is cheating.
• No points will be given for late pre-lab
• I. TITLE: should indicate what the lab was all about. II.
HYPOTHESES: Identify it as the hypothesis, tell what you predict will happen. Avoid “We are going to find out what will happen when…”
• III. METHODS:
a) Using few words or draw a flow chart b) Identify clearly the control group
c) Identify the dependent variable, d) Identify the independent variable,
f) Identify what is being measured and the units
being used. What method or time frame will be used for measurement? Example: I will take
reading of H2O consumption every 5 minutes for 30 minutes.
h) How will experimental results be presented? (graphs, charts)
What is Science??
• Write down a brief
Science is….
•
A process for evaluating
empirical knowledge; or the
organized body of knowledge
gained by this process
–
As a process, it helps us to
form beliefs about the world
around us
Methods of “Fixing Belief”
•
Tenacity:
repeat a belief until it is
accepted
– http://www.youtube.com/watch?v=IKZFrJI7n
rA&feature=related
•
Authority: rely on a noted
authority
– http://www.youtube.com/watch?v=DIlEv34d
KVI
•
Intuition: rely on common sense or
intuition
•
Scientific method: objective
The Scientific
Method
• Make an observation • Form a question
• Make an educated guess as to the answer ( a
hypothesis)
• Test your hypothesis
• Does the test support or disprove your
You can prove a guess False…
• If your tests prove that your
hypothesis was not correct, it means that AT LEAST some of the time, your hypothesis is wrong
BUT you
can’t
prove
a guess
True…
• If your test supports your guess, it
only means that your guess was
correct in THIS case, not in ALL cases
Why can’t you prove
something true???
• If I pick 1,000 M&M’s out of a bag, and all are
red, does that mean FOR SURE that all the M&M’s in the bag are red?
• Would you bet (insert highly valuable item
What kinds of questions can
we answer in this manner?
• Is the moon made of cheese?
• What are the costs and benefits of social
grooming in primates?
• Do dogs like to play fetch?
• Do dogs preferentially fetch bone-shaped
On a piece of
paper-• Write out one question that CAN be addressed
via the scientific method
• Write out one question that CANNOT be
Twinkies vs. Devildogs
• The problem: I am really hungry but really broke. • The question: Which is the better value?
• The observation: well, the ______sure looks bigger • Hypothesis: ______are a better value than _______
Summary:
• Science is not a collection of facts- it is an
The Vocab of the
Scientific Method
•
Hypothesis
- A formal, testable statement
•
Prediction
- What the investigator
believes the effect of the variable he/she
purposefully alters will be on the variable
he’she is interested in measuring
Independent Variable-
The parameter
deliberately varied by the investigator
Dependant Variable-
The parameter
measured by the investigator
Standardized Variable-
The parameters
that are kept equal throughout the
experiment
•
Replication
- Repeating the experiment
several times. This can occur at several
different levels
•
Sample Size-
The number of trials in an
Example:
• What is the effect of dietary calcium on bone
density in adult mice?
• Hypothesis:
– based on previous research found in the
literature, we believe that 500mg of calcium per day will lead to the densest mouse bones
• Prediction (if-then)
– Six month old mice fed 500mg a day of calcium for
Example (con’t)
• Independent variable:
– Level of calcium in the diet
• Dependent variable:
– Bone density of the mice
• Standardize:
– age, gender, initial weight, etc. of mice
• Control group:
• What hypothesis are you testing?
– What prediction is being tested?
• What is the independent variable? • What is the dependent variable?
• What are some variables that you should
http://us.mms.com/us/about/products/milkchocolate/
How to present your data
•
X axis for independent variable
•
Y axis for dependent variable
–
Label the axes with units!!!
•
Line graph for continuous independent
variables
•
Bar graph for qualitative or discontinuous
independent variables
Wrap Up
•
Know the terminology presented in the
slides
•
Replication is important if a researcher
wants to convince others of the validity
of his results
•
Observations must be done in an
Homework
• Design an experiment that addresses an
everyday problem
– Name the independent and dependent variables – Design any necessary controls
