Scientific Method Chapter 1: Section 2 How Scientists Work Notes

Scientific Method Definition Scientific Method Definition TTTThe scientific method is- AAAA logical and systematic approach or process to problem solving. AAAAn organized way of using evidence to learn about the natural world.

Then And Question Research Hypothesis Procedure/ Method Procedure/ Method Data Observations Conclusion What does the scientist want to learn more about? What does the scientist want to learn more about? Gathering of information An “Educated” guess of an answer to the question An “Educated” guess of an answer to the question Written and carefully followed step-by-step experiment designed to test the hypothesis Written and carefully followed step-by-step experiment designed to test the hypothesis Information collected during the experiment Information collected during the experiment Written description of what was noticed during the experiment Written description of what was noticed during the experiment Was the hypothesis correct or incorrect? Was the hypothesis correct or incorrect? Next Then Next And Finally First Scientific Method An Overview

1. Observing 1. Observing  Make an observation  See something unusual  Frogs with incorrect number of legs! As we all know, frogs have four legs. What’s up with these froggies?

Belief based on prior observations 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

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

Redi’s 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 in an Experiment  Variables - Factors that can be changed  Controlled Variables - all the variables that remain constant  Manipulated Variable - (also called the Independent Variable ) - factor in an experiment that a scientist purposely changes  Responding Variable- (also called the Dependent Variable ) - the outcome or results, factor in an experiment that may change because of the manipulated variable…. what a scientist wants to observe

Variables in Redi’s Experiment Variables in Redi’s Experiment CControlled Variables: jars, type of meat, location, temperature, time MManipulated Variables: gauze covering that keeps flies away from meat

Let’s think about this.… 1.W hich is the control group? 2.W hich is the experimental group? Two groups of Jars with meat Uncovered jars Covered jars Covered jars Uncovered jars

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

6. Collect and Record Data Types of Recorded Data Types of Recorded Data  Quantitative - observations that involve measurements/numbers; i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters  Qualitative - observations that do not involve numbers, are of a descriptive nature i.e. white maggots covered the meat, leaves were all wilting observations and measurements made in an experiment Data:

8. Draw Conclusions RRRRestate the hypothesis: Example: Flies produce maggots. AAAAccept or reject the hypothesis. SSSSupport your conclusion with specific, numerical data. WWWWhat was Redi’s conclusion? FFFFlies lay eggs too small to be seen. MMMMaggots found on rotting meat are produced from the eggs laid by flies. MMMMaggots are not appearing due to spontaneous generation!

SCIENTIFICSCIENTIFICSCIENTIFICSCIENTIFIC METHOD REV IEW

Can you put these steps in order? State the Hypothesis Make an Observation 1 the Problem 3 Determine Limitations 9 Define the Problem 2 Analyze Data 7 Report Results 10

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

Scientific Theory AAAA theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers

Scientific Law Scientific Law  Scientific laws represent the cornerstone of scientific discovery  They must be simple, true, universal, and absolute  If a law ever did not apply, then all science based upon that law would collapse Scientific Method