Scientific Method and Designing Your Cricket Experiment

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Scientific Methodand Designing Your Cricket
Experiment
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Initial Observation

• Use your senses to observe -be objective
  (measure), not subjective (opinions)
• See, hear, touch, taste, smell, etc.
• Can also use tools to measure (label numbers)
• Temperature, length, volume, etc.

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Observations Two Types

• Qualitative describe what we observe
• EX The flower has white petals.
• EX Bob has blue eyes.
• Quantitative measure what we observe
• EX The flower has seven petals.
• EX Bob has two eyes.

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Try to make quantitative observations out of
qualitative ones.

• Qualitative The dead fish is smelly.
• Quantitative You could ask a person to rate the
  smelliness from 1-5.

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TIPS FOR GOOD OBSERVATIONS

1. Be specific
2. Use numbers
3. Use terms others would understand
4. Avoid using emotions, good/bad, or opinions
5. This is not the time for critical
   evaluationsjust state the facts.

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Inference

• Reasonable conclusions or a hypothesis from
  observations youve made.
• Use judgments based on past experiences or and
  prior knowledge.

What inference can you make here?
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Which is the better observation?

• It is 58oF in the room.
• It is cool in the room.
• The iguana likes lettuce.
• The iguana consumed 90 of the lettuce.
• The bacteria is yucky.
• The bacteria has a slimy appearance and smells of
  sulfur.

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Problem Statement State the Question

• What is the effect of the independent variable
  on the dependent variable?
• What is the independent
• variable here?
• What is the dependent
• variable here?

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Which are Better Problem Statements?

• What is the effect of temperature on the height
  of plants grown in soil?
• How tall do plants get?
• Why does that fish always swim to the top?
• What is the effect of oxygen content on the water
  on the swimming location of a fish in a tank?

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Observing Crickets

• GET A DOZEN CRICKETS WITH A CUP (hand on top)-Put
  them in the tank w/lid, please.
• Make at least 10 observations and 10 inferences
• Write Problem Statements related to the
  observation

Observation Inference Problem Stat.
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PLAN CRICKET BEHAVIOR EXPERIMENT

• Laptops, if needed
• Refer to your articles

• Plan for the cricket behavior experiment-problem
  statement
• -experiment set-up
• (Independent and Dependent Variables)
• (Block - will run 3 trials, do test run today)

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Hypothesis

• Ifthen If producing oxygen bubbles in
  photosynthesis is related to light color, then
  green light will increase photosynthesis oxygen
  bubbles to form.
• Independent variable-varied by experimenter
• Dependent variable-changes as a result of the
  independent variable
• Prediction

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Hypothesis

• 1. Must be testable some way to check its
  validity
• 2. Must be falsifiable must be some experiment
  that could show that it is not true (may not
  prove to be false, just have to be able to test
  that)

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Can you test these to be falsifiable?Can you
rewrite these to be testable?

• 1. Animals are better than plants.
• 2. The average tree height on the HS campus is
  the same as on the MS campus.
• 3. How many angels does it take to dance on the
  head of a pin?

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Writing a problem statement and hypothesis for
your cricket behavior tips

• Sexual male vs. female
• Phototaxis how many crickets in diff. light
• Stimulus food or terrain preferences
• Courtship make a chart of beh. (touch, chirp,
  face direction, mount)
• Agonistic make chart of beh. (bite, jump toward,
  chirp, etc.)
• Territorial count crickets in areas (hut,
  leaves, by water, by food, by females)

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Experiment

• A. Independent Variable -what you change
• goes on the X-axis of the graph
• B. Dependent Variable -what changes as a result
  of what you did goes on the Y-axis of the graph

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Independent Variable?Dependent Variable?
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Experiment

• Constants-all the things in the experiment that
  stay the same
• same size Petri dishes
• Same agar medium
• Same type of bacteria

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What are some constants here?
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What constants are there in this experiment?
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• Control the part of the experiment that does
  not have the independent variable in it
• Use for reference, comparison
• Often the normal condition (no food, room light,
  room temp.)

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What is the control?
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L-added oxygenM-control(no gas added)R-added
carbon dioxide
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Do you think a placebo is a control?(inert pill,
one without the drug)

• EX some take Celebrex, some take a sugar pill

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Run the tests

• Record the data
• graphs
• charts
• video
• write observations
• measurements

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Celebrex Placebo ExperimentResults

• Have we proven that Celebrex (without a doubt)
  improves arthritis pain?
• What might be another explanation? Can we prove
  it false?

Placebo
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Conclusion

• Agree or disagree with the hypothesis

• The 10 spray produced taller plants.

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Repeat the Experiments

• Other scientists must be able to repeat your
  experiment with similar results to prove it true.
  OR they might prove it false.

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NOW YOU WILL DESIGN AND RUN AN EXPERIMENT

• RECEIVE CRICKET BEHAVIOR EXPERIMENT HANDOUT
• LAB GROUPS OF 4 (5)
• BEHAVIOR VARIABLE
• PLAN SET-UP
• RUN 3 TRIALS
• WRITE RESULTS

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DUE DATES

• August 25- (Mon.) Cricket Fact Sheet
• August 25/26 - (M/T)-Observe crickets
• August27-29- (w/Th/F)-Design Run Exp.
• Sept. 5 - (Fri.) Cricket Report Due