Scientific Method A problem solving process:

1. Recognize a Problem This deals with asking the question “How does that happen?” or “How does that work?”

2. Forming a Hypothesis When you form a hypothesis you are making an educated guess towards the answer to your question or problem. A hypothesis is often stated “if….then….”

2. Hypothesis Cont. A hypothesis is often stated “if….then….”

3. Experiment When you test your hypothesis, you run an experiment. During the experiment you follow a procedure or series of steps.

3. Experiment Cont. You observe what happens, and collect data (facts and figures) during the experiment.

4. Conclusion The last thing to do is to look at the observations and data that you collected and summarize what happened. This summary is your conclusion. Your conclusion can agree or disagree with your hypothesis.

Steps of Scientific Method in order State the Hypothesis Make an Observation the Problem Determine Limitations 9 Define the Problem 1 Analyze Data 2 Report Results

Experimenting  Let’s look at the text book example of the Scientific Method using Redi’s Experiment on Spontaneous Generation  He was trying to disprove the idea of Spontaneous Generation (or actually that flies came from maggots, which came from flies) Francesco Redi (1668)

Problem  Example: What creates maggots on meat?  Spontaneous generation once commonly accepted  Redi wanted to show what caused the appearance of maggots (and then flies) on meat

Belief based on prior observations  Redi observed that maggots appeared on meat a few days after flies were on meat  No microscope = no way to see eggs  But Redi believed that maggots came from eggs that were laid by flies

Hypothesis Redi’s Hypothesis: Flies produce maggots.  How could he test this?  Through a controlled experiment

Redi’s Controlled Experiment  Redi used two groups of jars  -Jars that contained meat and no cover  -Jars that contained meat and gauze cover Jars with meat Uncovered jars Covered jars

Variables CControls (Things that stay the same!): jars, type of meat, location, temperature, time VVariables(One thing you change): gauze covering that keeps flies away from meat

Let’s think about this.… 1.Which things stayed the same? hat one thing changed?

Let’s think about this.… 1.Which things stayed the same? Jars, meat, temperature, time. 2.What one thing changed? The cover.

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Manipulated Variables: gauze covering that keeps flies away from meat Uncovered jars Covered jars Several days pass Maggots appearNo maggots appear Responding Variable: whether maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. Controlled Variables: jars, type of meat, location, temperature, time Redi’s Experiment on Spontaneous Generation

Data  Examine data tables, charts, and graphs  Examine experimental notes  Look for trends, patterns, and averages  What does the data show  Put your data into words

Conclusion HHypothesis: Flies produce maggots. CConclusion: Only maggots were found in the jars with the flies. Flies produce maggots.

Example: PProblem: Will adding coffee grounds to a plant make it grow faster? HHypothesis: If I add coffee grounds to a plant, then it will grow faster.

CControls: What things stay the same:

CControls: What things stay the same: --type of plant --water amount --sunlight amount --temperature --soil

VVariable: What thing is changed: --coffee grounds

Exit: 11. What are the controls in an experiment? TThe controls are.... 22. What is the variable in an experiment? TThe variable is the...